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diff --git a/38290-h/38290-h.htm b/38290-h/38290-h.htm new file mode 100644 index 0000000..9ea2676 --- /dev/null +++ b/38290-h/38290-h.htm @@ -0,0 +1,7347 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> + <html xmlns="http://www.w3.org/1999/xhtml"> + <head> + <meta http-equiv="Content-Type" content="text/html;charset=ISO-8859-1" /> + <meta http-equiv="Content-Style-Type" content="text/css" /> + <title> + The Project Gutenberg eBook of Speciation And Evolution Of The Pygmy Mice, Genus Baiomys, by Robert L. Packard. + </title> + <style type="text/css"> + + p {text-align: justify; text-indent: 1.5em;} + sub, sup {font-size: 0.75em;} + sub {position: relative; top:-0.1em; left: -0.1em;} + sup {position: relative; bottom:-0.1em; right: -0.1em;} + table {margin-left: auto; padding:4px; margin-right: auto; + border-collapse: collapse;} + .brdtp {border-top: solid #000 1px;} + .brdtp2 {border-top: solid #000 2px;} + .brdbt {border-bottom: solid #000 1px;} + .brdbt2 {border-bottom: solid #000 2px;} + .brdlf {border-left: solid #000 1px;} + .pagenum {position: absolute; left: 92%; text-indent:0; font-size: 0.75em; + text-align: right; color: #b0b0b0;} + .pagenum2 {position: absolute; left: 92%; text-indent:0; + text-align: right; color: #b0b0b0;} + .references {margin-top: 0.5em; margin-left: 5.5em; text-indent: -3em;} + .vtop {vertical-align: top;} + .center {text-align: center;} + .text_lf {text-align: left;} + .text_rt {text-align: right;} + .smaller {font-size: 0.75em;} + .smcap {font-variant: small-caps;} + .caption1 {font-weight: bold; font-size:2.00em; margin-top: 2em; text-align: center;} + .caption2 {font-weight: bold; font-size:1.50em; margin-top: 1.5em; text-align: center;} + .caption3 {font-size:1.15em; margin-top: 1em; text-align: center;} + .trans_notes {background:#d0d0d0; padding: 7px; border:solid black 1px;} + .species_ref {margin-left: 2.5em; text-indent: -2.5em; margin-top: 1em; + margin-bottom: 1em; text-align: justify;} + .hr25 {color:#000; width: 25%;} + .footnote {margin-left: 10%; margin-right: 10%; font-size: 0.9em;} + .footnote .label {position: absolute; right: 84%; text-align: right;} + .fnanchor {vertical-align: super; font-size: .8em; text-decoration: none;} + .fig_center {margin: auto; text-align: center;} + .fig_caption {text-align: center; margin-bottom:1.5em;} + .book {margin-left: 10%; margin-right: 10%; margin-top: 2em; margin-bottom:2em;} + + </style> + </head> +<body> + + +<pre> + +The Project Gutenberg EBook of Speciation and Evolution of the Pygmy Mice, +Genus Baiomys, by Robert L. Packard + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Speciation and Evolution of the Pygmy Mice, Genus Baiomys + +Author: Robert L. Packard + +Release Date: December 13, 2011 [EBook #38290] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SPECIATION AND EVOLUTION OF *** + + + + +Produced by Chris Curnow, Tom Cosmas, Joseph Cooper and +the Online Distributed Proofreading Team at +http://www.pgdp.net + + + + + + +</pre> + + +<div class="book"><!-- Begin Book --> + +<div class="fig_center" style="width: 313px;"> +<img src="images/cover.jpg" width="313" height="524" alt="cover" /><br /> +<div class="smaller">[Transcriber's Note: Cover compiled from scanned images.]</div> +<br /> +</div> + +<p><span class="pagenum"><a name="Page_579" id="Page_579">[Pg 579]</a></span></p> +<div class="center"> +<div class="fig_center"> +<img src="images/bar_double.png" width="100%" height="15" alt="" /> +</div> +<span class="smcap">University of Kansas Publications</span><br /> +<br /> +<span class="smcap">Museum of Natural History</span><br /> +<br /> +<hr class="hr25" /> +<br /> +Volume 9, No. 23, pp. 579-670, 4 pls., 12 figs. in text<br /> +<br /> +<img src="images/bar_single.png" width="40%" height="15" alt="" /> + June 16, 1960 +<img src="images/bar_single.png" width="40%" height="15" alt="" /><br /> +<br /> +<br /> +<div class="caption1">Speciation and Evolution of the<br /> +Pygmy Mice, Genus Baiomys</div> +<br /> +<div class="caption3"><b>BY</b></div> +<br /> +<div class="caption2">ROBERT L. PACKARD</div> +<br /> +<span class="smcap">University of Kansas</span><br /> +<span class="smcap">Lawrence</span><br /> +1960<br /> +<br /> +</div> + +<p><span class="pagenum"><a name="Page_580" id="Page_580">[Pg 580]</a></span></p> +<div class="center"> +<span class="smcap">University of Kansas Publications, Museum of Natural History</span><br /> +<br /> +Editors: E. Raymond Hall, Chairman, Henry S. Fitch,<br /> +<br /> +Robert W. Wilson<br /> +<br /> +Volume 9, No. 23, pp. 579-670, 4 pls., 12 figs. in text<br /> +Published June 16, 1960<br /> +<br /> +<br /> +<span class="smcap">University of Kansas</span><br /> +Lawrence, Kansas<br /> +<br /> +<br /> +PRINTED IN<br /> +THE STATE PRINTING PLANT<br /> +TOPEKA, KANSAS<br /> +<br /> +1960<br /> +<br /> +<img src="images/union_label.png" width="74" height="27" alt="Look for the Union Label" /><br /> +28-3030<br /> +<br /> +<br /> +</div> + +<p><span class="pagenum"><a name="Page_581" id="Page_581">[Pg 581]</a></span></p> +<div class="caption2"><a name="Speciation_and_Evolution_of_the" id="Speciation_and_Evolution_of_the"></a>Speciation and Evolution of the +Pygmy Mice, Genus Baiomys</div> + +<div class="caption3"><b>BY</b></div> + +<div class="caption2">ROBERT L. PACKARD</div> +<br /> + +<div class="caption2"><a name="CONTENTS" id="CONTENTS"></a>CONTENTS</div> + + +<table width="80%" summary="Contents"> +<tr> + <td> </td> + <td>PAGE</td> +</tr> +<tr> + <td><a href="#INTRODUCTION">Introduction</a></td> + <td class="text_rt">583</td> +</tr> +<tr> + <td class="text_lf"><a href="#MATERIALS_METHODS_AND_ACKNOWLEDGMENTS">Materials, Methods and Acknowledgments</a></td> + <td class="text_rt">584</td> +</tr> +<tr> + <td class="text_lf"><a href="#PALEONTOLOGY_OF_THE_GENUS">Paleontology of the Genus</a></td> + <td class="text_rt">587</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_sawrockensis"><i>Baiomys sawrockensis</i></a></td> + <td class="text_rt">588</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_rexroadi"><i>Baiomys rexroadi</i></a></td> + <td class="text_rt">589</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_kolbi"><i>Baiomys kolbi</i></a></td> + <td class="text_rt">590</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_brachygnathus"><i>Baiomys brachygnathus</i></a></td> + <td class="text_rt">590</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_minimus"><i>Baiomys minimus</i></a></td> + <td class="text_rt">591</td> +</tr> +<tr> + <td class="text_lf"><a href="#PHYLETIC_TRENDS">Phyletic trends</a></td> + <td class="text_rt">592</td> +</tr> +<tr> + <td class="text_lf"><a href="#NON-GEOGRAPHIC_VARIATION">Non-Geographic Variation</a></td> + <td class="text_rt">595</td> +</tr> +<tr> + <td class="text_lf"> <a href="#VARIATION_WITH_AGE">Variation with age</a></td> + <td class="text_rt">595</td> +</tr> +<tr> + <td class="text_lf"> <a href="#SECONDARY_SEXUAL_VARIATION">Secondary sexual variation</a></td> + <td class="text_rt">597</td> +</tr> +<tr> + <td class="text_lf"> <a href="#INDIVIDUAL_VARIATION">Individual variation</a></td> + <td class="text_rt">597</td> +</tr> +<tr> + <td class="text_lf"> <a href="#PELAGE_AND_MOLTS">Pelage and molts</a></td> + <td class="text_rt">598</td> +</tr> +<tr> + <td class="text_lf"><a href="#TAXONOMIC_CHARACTERS_AND_RELATIONSHIPS">Taxonomic Characters and Relationships</a></td> + <td class="text_rt">600</td> +</tr> +<tr> + <td class="text_lf"> <a href="#External_parts">External parts</a></td> + <td class="text_rt">600</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Pelage">Pelage</a></td> + <td class="text_rt">600</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Skull">Skull</a></td> + <td class="text_rt">600</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Teeth">Teeth</a></td> + <td class="text_rt">601</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Hyoid_apparatus">Hyoid apparatus</a></td> + <td class="text_rt">601</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baculum">Baculum</a></td> + <td class="text_rt">603</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Auditory_ossicles">Auditory ossicles</a></td> + <td class="text_rt">605</td> +</tr> +<tr> + <td class="text_lf"><a href="#Genus_Baiomys">Genus Baiomys</a></td> + <td class="text_rt">607</td> +</tr> +<tr> + <td class="text_lf"><a href="#SYSTEMATIC_ACCOUNTS">Systematic Accounts of Species and Subspecies</a></td> + <td class="text_rt">608</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_musculus"><i>Baiomys musculus</i></a></td> + <td class="text_rt">608</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_musculus_brunneus"><i>Baiomys musculus brunneus</i></a></td> + <td class="text_rt">612</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_musculus_grisescens"><i>Baiomys musculus grisescens</i></a></td> + <td class="text_rt">614</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_musculus_handleyi"><i>Baiomys musculus handleyi</i></a></td> + <td class="text_rt">617</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_musculus_infernatis"><i>Baiomys musculus infernatis</i></a></td> + <td class="text_rt">618</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_musculus_musculus"><i>Baiomys musculus musculus</i></a></td> + <td class="text_rt">620</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_musculus_nigrescens"><i>Baiomys musculus nigrescens</i></a></td> + <td class="text_rt">623</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_musculus_pallidus"><i>Baiomys musculus pallidus</i></a> + <span class="pagenum"><a name="Page_582" id="Page_582">[Pg 582]</a></span></td> + <td class="text_rt">625</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_musculus_pullus"><i>Baiomys musculus pullus</i></a></td> + <td class="text_rt">628</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_taylori"><i>Baiomys taylori</i></a></td> + <td class="text_rt">630</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_taylori_allex"><i>Baiomys taylori allex</i></a></td> + <td class="text_rt">633</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_taylori_analogous"><i>Baiomys taylori analogous</i></a></td> + <td class="text_rt">637</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_taylori_ater"><i>Baiomys taylori ater</i></a></td> + <td class="text_rt">640</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_taylori_canutus"><i>Baiomys taylori canutus</i></a></td> + <td class="text_rt">643</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_taylori_fuliginatus"><i>Baiomys taylori fuliginatus</i></a></td> + <td class="text_rt">645</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_taylori_paulus"><i>Baiomys taylori paulus</i></a></td> + <td class="text_rt">647</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_taylori_subater"><i>Baiomys taylori subater</i></a></td> + <td class="text_rt">650</td> +</tr> +<tr> + <td class="text_lf"> <a href="#Baiomys_taylori_taylori"><i>Baiomys taylori taylori</i></a></td> + <td class="text_rt">651</td> +</tr> +<tr> + <td class="text_lf"><a href="#EVOLUTION_AND_SPECIATION">Evolution and Speciation</a></td> + <td class="text_rt">655</td> +</tr> +<tr> + <td class="text_lf"> <a href="#FORMATION_OF_THE_RECENT_SPECIES">Formation of the Recent Species</a></td> + <td class="text_rt">658</td> +</tr> +<tr> + <td class="text_lf"> <a href="#AREAS_OF_PRESENT_DIFFERENTIATION">Areas of present differentiation</a></td> + <td class="text_rt">661</td> +</tr> +<tr> + <td class="text_lf"> <a href="#ZOOGEOGRAPHIC_POSITION">Zoogeographic position</a></td> + <td class="text_rt">661</td> +</tr> +<tr> + <td class="text_lf"><a href="#CONCLUSIONS">Conclusions</a></td> + <td class="text_rt">664</td> +</tr> +<tr> + <td class="text_lf"><a href="#LITERATURE_CITED">Literature Cited</a></td> + <td class="text_rt">665</td> +</tr> +</table> +<br /> +<br /> + +<p><span class="pagenum"><a name="Page_583" id="Page_583">[Pg 583]</a></span></p> + +<div class="caption2"><a name="INTRODUCTION" id="INTRODUCTION"></a>INTRODUCTION</div> + +<p>Pygmy mice (<i>Genus Baiomys</i>) are the smallest cricetine rodents +in North America. They occur from Nicaragua in Central America +into the southwestern United States. The principal part of the +geographic range of the pygmy mice lies in the Republic of México. +They are notably common in central México, but are only locally +common to the north and to the south, and then only in certain +seasons.</p> + +<p>Pygmy mice were first brought to the attention of biologists in +1887 when Oldfield Thomas described a diminutive species of +cricetine rodent, <i>Hesperomys</i> (<i>Vesperimus</i>) <i>taylori</i>. The description +was based on a specimen obtained by William Taylor from San +Diego, Duval County, Texas. C. Hart Merriam (1892:70) described +<i>Sitomys musculus</i> on the basis of specimens from Colima +[City of], Colima, México. Merriam (<i>loc. cit.</i>) mentioned that the +two kinds of mice, <i>Hesperomys taylori</i> and <i>Sitomys musculus</i>, "in +general appearance look almost precisely like the common house +mouse (<i>Mus musculus</i>) but are still smaller and have shorter tails." +He placed the two species in the genus <i>Sitomys</i>. Frederick +W. True in 1894 regarded them as composing a distinct subgenus +of <i>Sitomys, Baiomys</i>. According to True (1894:758), <i>S. +taylori</i> and <i>S. musculus</i> possessed a different combination of characters +(ascending ramus of mandible short and erect, condyle terminal, +coronoid process well-developed, uncinate, and near the condyle, +size small, tail short, plantar tubercles six, soles hairy) than +either <i>Vesperimus</i>, or <i>Onychomys</i> (which had been considered as a +subgenus of <i>Hesperomys</i> until 1889). In 1907, E. A. Mearns accorded +<i>Baiomys</i> generic rank. Osgood (1909:252) treated <i>Baiomys</i> +us a subgenus of <i>Peromyscus</i>, whereas, Miller, in 1912, regarded +<i>Baiomys</i> as a distinct genus. Most recent students of North American +mammals have followed Miller, but usually with reservations. +Ellerman (1941:402) emphasized that the taxonomic position of the +genus was uncertain, and wrote that <i>Baiomys</i> "… seems to be +considerably distinct from <i>Peromyscus</i>, and may perhaps be a +northern representative of <i>Hesperomys</i> or one of the small South +American genera."</p> + +<p>Only two comprehensive analyses of geographic variation and +interspecific taxonomic relationships have been made; the first was +by Osgood (1909) who had fewer than a fourth of the specimens of +<i>Baiomys</i> available to me; the second was by Hooper (1952a:90-97) +<span class="pagenum"><a name="Page_584" id="Page_584">[Pg 584]</a></span> +who contributed importantly to understanding the relationships of +the two living species in central México. No attempts heretofore +have been made to correlate and understand the relationships of the +five fossil species to one another and to the living species assigned +to the genus.</p> + +<p>Six objectives of the following report are to: (1) list characters +taxonomically useful in recognizing species and subspecies; (2) +record amount of variation within and between populations; (3) +correlate observed variations with known biological principles; (4) +show geographic ranges of the two living species; (5) indicate relationships +between fossil and living species of the genus; and (6) +clarify the systematic position of the genus.</p> + + +<div class="caption2"><a name="MATERIALS_METHODS_AND_ACKNOWLEDGMENTS" id="MATERIALS_METHODS_AND_ACKNOWLEDGMENTS"></a>MATERIALS, METHODS AND ACKNOWLEDGMENTS</div> + + +<p>This report is based on the study of approximately 3,520 museum +study skins, skulls, complete skeletons, and entire animals preserved +in liquid. Most specimens examined were accompanied by an attached +label bearing data on locality and date of capture, name of +collector, external measurements, and sex. In addition, 49 fossil +specimens referable to <i>Baiomys</i> were studied. Nearly two-thirds +of the specimens were assembled at the University of Kansas Museum +of Natural History; the remainder were examined in other +institutions.</p> + +<p>Specimens studied were grouped by geographic origin, sex, age, +and season of capture. Individual variation was then measured in +several of the larger samples of each living species and in measurable +fossil material. External measurements used were those recorded +by the collectors on the labels attached to the skins. Twenty +cranial measurements employed in the past in the study of <i>Baiomys</i> +and closely related cricetine rodents were statistically analyzed. +The coefficient of variation was calculated for each of the 20 measurements +in order to determine which varied least. In general, +measurements having the least coefficient of variation were used +in comparing samples from different geographic areas. <a href="#fig1">Figure 1</a> +shows the points between which measurements were taken.</p> + +<div class="smaller"> +<i>Occipitonasal length.</i>—From anteriormost projection of nasal bones to posteriormost +projection of supraoccipital bone. <i>A</i> to <i>A'</i> + +<i>Zygomatic breadth.</i>—Greatest distance across zygomatic arches of cranium at +right angles to long axis of skull. <i>B</i> to <i>B'</i> + +<i>Postpalatal length.</i>—From posterior margin of hard palate to anterior margin +of foramen magnum. <i>C</i> to <i>C'</i> + +<i>Least interorbital breadth.</i>—Least distance across top of skull between orbits. +<i>D</i> to <i>D'</i> +<span class="pagenum2"><a name="Page_585" id="Page_585">[Pg 585]</a></span> +<i>Length of incisive foramina.</i>—From anteriormost point to posteriormost point +of incisive foramina. <i>E</i> to <i>E'</i> + +<i>Length of rostrum.</i>—The distance in a straight line from the notch that lies +lateral to the lacrimal to the tip of the nasal on the same side. <i>F</i> to <i>F'</i> + +<i>Breadth of braincase.</i>—Greatest distance across braincase, taken at right angles +to long axis of skull. <i>G</i> to <i>G'</i> + +<i>Depth of cranium.</i>—The distance from the dorsalmost part of the braincase to +a flat plane touching tips of incisors and ventral border of each auditory +bulla. A glass slide one millimeter thick was placed on the ventral side of +the skull. One jaw of the caliper was on the lower surface of the slide and +the other jaw on the dorsalmost part of the braincase. The depth of the +slide was subtracted from the total reading. <i>H</i> to <i>H'</i> + +<i>Alveolar length of maxillary tooth-row.</i>—From anterior border of alveolus of +M1 to posterior alveolus of M3. <i>I</i> to <i>I'</i> +</div> + +<div class="fig_center"> +<a name="fig1" id="fig1"></a> +<img src="images/fig_1.png" width="425" height="201" alt="" /><br /> +<span class="fig_caption"><span class="smcap">Fig. 1.</span> Three views of the skull to show points between which measurements +were taken.<br />Based on <i>B. m. pullus</i>, adult, female, No. 71611 KU, 8 mi. S +Condega, Estelí, Nicaragua. × 1<sup>1</sup>/<sub>3</sub>.</span> +</div> + +<p>Capitalized color-terms refer to Ridgway (1912). Color terms without +initial letters capitalized do not refer to any one standard.</p> + +<p>The names of the cusps and ridges of the teeth (see <a href="#fig2">Figure 2</a>) are those +suggested by Wood and Wilson (1936:389-390). Terminology of the enamel +grooves and folds is that of Hershkovitz (1944:17) and Hooper (1952b:20-21).</p> + +<p>Because secondary sexual variation was not significant (see <a href="#Page_597">page 597</a>), both +males and females of like age and pelage were used in comparisons of samples +designed to reveal geographic variation.</p> + +<p>The species are arranged from less to more progressive; the subspecies are +arranged alphabetically.</p> + +<p>In the synonymy of each subspecies, the plan has been to cite: (1) the +name first proposed; (2) the first usage of the name combination employed +by me; (3) all other name combinations in chronological order that have been +applied to the subspecies concerned.</p> + +<p>The localities of specimens examined are listed by country from north to +south. Within a country, the listing is by state, beginning with the northwesternmost +state and proceeding by tiers (west to east) to the southeasternmost +state. Within a state of the United States, the listing is by counties in the +same geographic order as described for states. Within any county in the +United States, within any state in México, and within any country in Central +America, the listing of localities is from north to south. When more than +one locality is on the same line of latitude, the westernmost locality is listed +first. Marginal localities for each subspecies are listed in a paragraph at the +end of each account. Each marginal locality is mapped by means of a circle. +The circles are listed in clockwise order, beginning with the northernmost. +When more than one of these localities lies on the same line of latitude, the +westernmost is cited first. Localities not represented on the distribution maps, +so as to avoid undue crowding of symbols, are italicized in the lists of specimens +examined.</p> + +<p><span class="pagenum"><a name="Page_586" id="Page_586">[Pg 586]</a></span></p> +<div class="fig_center"> +<a name="fig2" id="fig2"></a> +<img src="images/fig_2.png" width="470" height="509" alt="" /><br /> +<div class="fig_caption"><span class="smcap">Fig. 2.</span> Occlusal views of molars. × 13.<br /> +<br /> +<table style="text-align: left" summary="teeth"> +<tr> + <td class="vtop">A.</td> + <td><i>B. taylori analogous</i>, subadult, female, No. 28102 KU, 4 km. ENE Tlalmanalco, + 2290 meters, Estado de México. Right, upper molars.</td> +</tr> +<tr> + <td class="vtop">B.</td> + <td><i>B. musculus musculus</i>, subadult, male, No. 45456 USNM, Colima, Colima, + México. Left, upper molars.</td> +</tr> +<tr> + <td class="vtop">A'.</td> + <td><i>B. taylori analogous</i>, subadult, female, No. 28102 KU 4 km. ENE Tlalmanalco, + 2290 meters, Estado de México. Left, lower molars.</td> +</tr> +<tr> + <td class="vtop">B'.</td> + <td><i>B. musculus musculus</i>, subadult, male, No. 45456 USNM, Colima, Colima, + México. Right, lower molars.</td> +</tr> +</table> +<br /> +</div> +</div> + +<p><span class="pagenum"><a name="Page_587" id="Page_587">[Pg 587]</a></span></p> + +<p>The largest single collection of pygmy mice is in the University of Kansas +Museum of Natural History, and, unless otherwise indicated, specimens cited in +the taxonomic accounts beyond are there.</p> + +<p>I am indebted to the following named institutions and persons for making +specimens available for study:</p> + +<div class="references"> American Museum of Natural History, G. G. Goodwin and R. G. VanGelder.</div> + +<div class="references"> Carnegie Museum, J. K. Doutt.</div> + +<div class="references"> California Academy of Sciences, Robert T. Orr.</div> + +<div class="references"> Chicago Natural History Museum, Phillip H. Hershkovitz.</div> + +<div class="references"> Cleveland Museum of Natural History (Collection now a part of Museum of +Zoology, University of Michigan, W. H. Burt, E. T. Hooper).</div> + +<div class="references"> Louisiana State University, Museum of Natural History, George H. +Lowery, Jr.</div> + +<div class="references"> Los Angeles County Museum, Charles A. McLaughlin.</div> + +<div class="references"> United States National Museum (Biological Survey Collections), David A. +Johnson, and Viola S. Schantz.</div> + +<div class="references"> United States National Museum, Division of Vertebrate Paleontology, C. +Lewis Gazin.</div> + +<div class="references"> University of Arizona, E. L. Cockrum, and G. VR. Bradshaw.</div> + +<div class="references"> University of California, Museum of Vertebrate Zoology, Seth B. Benson, +and W. Z. Lidicker.</div> + +<div class="references"> University of Illinois, Museum of Natural History, Donald F. Hoffmeister.</div> + +<div class="references"> University of Michigan, Museum of Zoology, W. H. Burt, E. T. Hooper, and +Claude W. Hibbard.</div> + +<div class="references"> University of New Mexico, James S. Findley.</div> + +<div class="references"> University of Texas, Frank W. Blair.</div> + +<div class="references"> Texas A & M, Cooperative Wildlife Research Collection, W. B. Davis.</div> + +<div class="references"> The Museum, Michigan State University, Rollin H. Baker.</div> + +<div class="references"> University of Florida Collections, James N. Layne.</div> + +<p>I am especially grateful to Professor E. Raymond Hall who guided me in +my study and gave critical assistance with the manuscript. Additional appreciated +suggestions were made by Professors A. Byron Leonard, Robert W. Wilson, +Henry S. Fitch, Ronald L. McGregor, and fellow graduate students. For the +illustrations, I am indebted to Mrs. Lorna Cordonnier, Miss Lucy Remple and +Mrs. Connie Spitz. Mr. B. J. Wilks of the University of Texas, Department +of Zoology, provided a number of living pygmy mice for study in captivity. +Mr. J. Raymond Alcorn and his son, Albert, collected a large share of specimens +of pygmy mice now in the University of Kansas, Museum of Natural History. +My wife, Patricia, aided me in secretarial work and typing of the manuscript.</p> + +<p>For financial assistance, I am indebted to the National Science Foundation +when I was a Research Assistant, to the Sigma Xi-RESA Research Fund for a +Grant-in-Aid, and to the Kansas University Endowment Association through +its A. Henley Aid Fund, and the Watkins Fund for out-of-state field work by +the Museum of Natural History.</p> + + +<div class="caption2"><a name="PALEONTOLOGY_OF_THE_GENUS" id="PALEONTOLOGY_OF_THE_GENUS"></a>PALEONTOLOGY OF THE GENUS</div> + +<p>Five fossil species, all extinct, have been assigned to the genus +and range in time from early late Pliocene (Saw Rock Canyon +fauna of Hibbard, 1953:408) to Mid-Pleistocene (see Hibbard, +<span class="pagenum"><a name="Page_588" id="Page_588">[Pg 588]</a></span> +1958:25, who assigns the Curtis Ranch fauna to late Kansan or +early Yarmouth).</p> + +<p>I examined all known fossil material and compared it with Recent +material. When the antiquity of the genus is considered, the degree +of difference between the oldest fossil species and the two living +species is much less than might be expected.</p> + + +<div class="caption3"><a name="Baiomys_sawrockensis" id="Baiomys_sawrockensis"></a> +<b>Baiomys sawrockensis</b> Hibbard</div> + +<div class="species_ref"><i>Baiomys sawrockensis</i> Hibbard, Papers Mich. Acad. Sci., Arts and Letters, +38:402, April 27, 1953.</div> + +<div class="smaller"> +<p><i>Type.</i>—No. 27506, Univ. Michigan; left mandibular ramus bearing m1-m3 +and incisor; Saw Rock Canyon, early late Pliocene, XI member of the Rexroad +formation, sec. 36, T. 34 S, R. 31 W, Seward County, Kansas (University +of Kansas, Locality 6).</p> + +<p><i>Referred material.</i>—Univ. Michigan, Nos. 25781, 27503-27505, 28159-28165, +29708-29715, 31015.</p> + +<p><i>Diagnosis.</i>—Ramus of medium size to small for the genus; lower incisor +broad, moderately recurved; diastemal region broad; anterior median fold +between anterior labial conulid and anterior lingual conulid of m1 deep; primary +first fold between anteroconulid and protoconid of m2 deep; cingular +ridge (ectolophid) at entrance to posteroexternal reëntrant valley (major fold, +see <a href="#fig2">Figure 2</a>) between protoconid and hypoconid of m1 and m2; average +and extreme measurements of lower molar row of eight specimens are, 2.65 +(2.5-2.7).</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. brachygnathus</i>, see account of that +species. From <i>B. rexroadi</i>, <i>B. sawrockensis</i> differs in: anterior median fold of +m1 deeper; incisor narrower; diastemal region broader; coronoid process +broader and better developed; cingular ridges (ectolophids and mesolophids) +more pronounced in their development; incisors less proödont, more retrodont.</p> + +<p>From <i>B. kolbi</i>, <i>B. sawrockensis</i> differs in: crowns of molars narrower; +incisors less proödont; cingular ridges (ectolophids and mesolophids) of m1 +and m2 more pronounced in their development.</p> + +<p>From <i>B. minimus</i>, <i>B. sawrockensis</i> differs in: incisor less procumbent; +masseteric ridge extending farther anteriorly; anterior cingulum of m2 slightly +larger.</p> + +<p>From <i>B. musculus</i>, <i>B. sawrockensis</i> differs in: over-all size of jaw and +molar row less; diastema more acutely curved; incisors shorter; anterior +median fold of m1 slightly deeper.</p> + +<p>From <i>B. taylori</i>, <i>B. sawrockensis</i> differs in: m1 and m2 smaller; cingular +ridges in m1 and m2 more pronounced; anterolingual conulid farther forward; +incisors shorter, more proödont; molar teeth depressed, less hypsodont; diastemal +region broader, more acutely curved; masseteric ridge not extending so +far anteriorly.</p> +</div> + +<p><i>Remarks.</i>—<i>B. sawrockensis</i> is the oldest known pygmy mouse. +The extreme development of the anterior median fold between the +<span class="pagenum"><a name="Page_589" id="Page_589">[Pg 589]</a></span> +anterolingual conulid and the anterolabial conulid is regarded as a +primitive feature in the pygmy mice. In this character, the Recent +species can be traced back in time through <i>B. minimus</i> to <i>B. sawrockensis</i>. +<i>B. sawrockensis</i> resembles <i>Calomys laucha</i> of South +America in general conformation of jaw and tooth structure. The +molars of <i>sawrockensis</i> are smaller than those of <i>C. laucha</i>, and +the anterolingual conulid of <i>sawrockensis</i> is farther forward.</p> + + +<div class="caption3"><a name="Baiomys_rexroadi" id="Baiomys_rexroadi"></a> +<b>Baiomys rexroadi</b> Hibbard</div> + +<div class="species_ref"><i>Baiomys rexroadi</i> Hibbard, Amer. Midland Nat., 26:351, September, 1941; +Hibbard, Contrib. Mus. Paleo., Univ. Michigan, 8(2):145, June 29, 1950 +(part); Hibbard, Papers Mich. Acad. Sci., Arts and Letters, 38:403, +April 27, 1953.</div> + +<div class="smaller"> +<p><i>Type.</i>—No. 4670, Univ. Kansas; left mandibular ramus bearing m1-m3, and +incisor; Rexroad fauna, Locality no. 2, Upper Pliocene, Meade County, Kansas.</p> + +<p><i>Referred material.</i>—Univ. of Michigan Nos. 24840, 24851, 27493, 27496, +27501, 28862-28867.</p> + +<p><i>Diagnosis.</i>—Ramus medium in size for the genus; incisors small, proödont; +anterior median fold of m1 slight; cingulum of all molars poorly developed; +average and external measurements of lower molar row of seven specimens +are, 2.7 (2.6-3.0).</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. sawrockensis</i> and <i>B. minimus</i>, see +accounts of those species. From <i>B. kolbi</i>, <i>B. rexroadi</i> differs in: over-all size +of mandibular ramus, incisors, and molars smaller; anterior median fold of m1 +present, though poorly developed.</p> + +<p>From <i>B. brachygnathus</i>, <i>B. rexroadi</i> differs in: over-all size of mandibular +ramus smaller; m3 larger; posterior cusps (hypoconid and entoconid) elongated; +diastema shorter, less acutely recurved; incisors less proödont; cingular +ridges of m1 and m2 less well-developed.</p> + +<p>From <i>B. musculus</i>, <i>B. rexroadi</i> differs in: over-all size of mandibular ramus +less; cingular ridges of m1 and m2 less well-developed; incisors smaller, more +proödont; molars less depressed.</p> + +<p>From <i>B. taylori</i>, <i>B. rexroadi</i> differs in: m3 more triangular, posterior part +narrower; mental foramen closer to anterior root of m1; masseteric ridge closer +to alveolus of m1; incisor shorter, more proödont; molars more depressed.</p> +</div> + +<p><i>Remarks.</i>—Two maxillary tooth-rows and associated parts were +studied. On one of these specimens, the M2 has a well-developed +mesostyle; the anterior median fold of M1 is also well-developed. +The other specimen possesses a low cingular ridge (enteroloph) +between the protocone and the hypocone, a reduced cingular +ridge (mesoloph) between the paracone and metacone of M1. +On the second molar, M2, a mesostyle joins with the mesoloph +somewhat in the fashion indicated by Hooper (1957:9, encircled +number 2).</p> + +<p><span class="pagenum"><a name="Page_590" id="Page_590">[Pg 590]</a></span></p> + +<div class="caption3"><a name="Baiomys_kolbi" id="Baiomys_kolbi"></a> +<b>Baiomys kolbi</b> Hibbard</div> + +<div class="species_ref"><i>Baiomys kolbi</i> Hibbard, Trans. Kansas Acad. Sci., 55:201, June 18, 1952; +Hibbard, Papers Mich. Acad. Sci., Arts and Letters, 38:403, April 27, +1953.</div> + +<div class="smaller"> +<p><i>Type.</i>—No. 24846, Univ. Michigan; right mandibular ramus bearing m1-m3 +and incisor; Fox Canyon, upper Pliocene, Rexroad formation, Rexroad fauna, +Univ. Michigan Locality K1-47, sec. 35, T. 34 S, R. 30 W, XI Ranch, Meade +County, Kansas.</p> + +<p><i>Referred material.</i>—Univ. Michigan Nos. 24845-24848, 27494, 27497, +27499, 28566, 28861, 28878, 28880-28882, 28884, 28886.</p> + +<p><i>Diagnosis.</i>—Ramus of medium size to large for the genus; lower incisor +short, narrow transversely, proödont; anterior median fold of m1 reduced or +absent; cingular ridges of m1 and m2 moderately well-developed; m3 large +relative to m1 and m2; average and extreme measurements of lower molars +of seven specimens are, 3.0 (3.0-3.1).</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. sawrockensis</i> and <i>B. rexroadi</i>, see +accounts of those species. From <i>B. brachygnathus</i>, <i>B. kolbi</i> differs in: molar +row longer; m3 and jaw larger; diastema longer; masseteric ridge not so far +forward; molars more depressed.</p> + +<p>From <i>B. minimus</i>, <i>B. kolbi</i> differs in: molar row longer; m3 larger; jaw +larger; diastema not so acutely curved; incisor shorter, narrower transversely, +more proödont.</p> + +<p>From <i>B. musculus</i>, <i>B. kolbi</i> differs in: anterior median fold of m1 slightly +developed or absent, instead of well-developed; m3 larger (not reduced), +external reëntrant valley broad and extending farther across crown of tooth; +incisor smaller, and more proödont; cingular ridges of m1 and m2 less well-developed.</p> + +<p>From <i>B. taylori</i>, <i>B. kolbi</i> differs in: molars larger, more depressed; incisor +shorter, more proödont; m3 smaller relative to m1 and m2; external reëntrant +valley of m3 broad, extending farther across crown of tooth.</p> +</div> + +<p><i>Remarks.</i>—The slight development or absence of the anterior +median fold in <i>kolbi</i> suggests that it was specialized. The anterior +median fold is well-developed in all species of <i>Baiomys</i> save <i>B. +brachygnathus</i> and <i>B. taylori</i>, in which the fold is only slightly developed +or absent. <i>B. kolbi</i> may have paralleled <i>B. taylori</i> in specialization +for a diet of grasses and for a life in open country.</p> + + +<div class="caption3"><a name="Baiomys_brachygnathus" id="Baiomys_brachygnathus"></a> +<b>Baiomys brachygnathus</b> (Gidley)</div> + +<div class="species_ref"><i>Peromyscus brachygnathus</i> Gidley, U. S. Geol. Surv. Prof. Papers, 131:124, +March 15, 1922.</div> + +<div class="species_ref"><i>Baiomys brachygnathus</i>, Hibbard, Amer. Midland Nat., 26:352, September, +1941.</div> + +<div class="species_ref"><i>P. [eromyscus] brachygnathus</i>, Wilson, Carnegie Inst. Washington Publ., +473:33, May 21, 1936.</div> + +<div class="smaller"> +<p><i>Type.</i>—No. 10501, U. S. Nat. Mus.; right mandibular ramus bearing m1-m3, +and incisor; 2 mi. NE Curtis Ranch house, near a line between sec. 28 and 29, +T. 18 S, R. 21 E, Mid-Pleistocene (Hibbard, 1958:25), Cochise County, +Arizona.</p> + +<p><span class="pagenum2"><a name="Page_591" id="Page_591">[Pg 591]</a></span></p> + +<p><i>Referred material.</i>—None.</p> + +<p><i>Diagnosis.</i>—Ramus small for the genus; m3 reduced; jaw reduced anteroposteriorly; +incisor short, slender, proödont; cingular ridges well-developed, +posterior ectolophid continuous from protoconid to hypoconid in m1 and m2; +diastema short; length of molar row 2.8 mm.</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. rexroadi</i> and <i>B. kolbi</i>, see accounts +of those species. From <i>B. minimus</i>, <i>B. brachygnathus</i> differs in: jaw not so +slender anteriorly; masseteric ridge not so far anterior; cheek-teeth slightly +broader, less depressed, therefore, more hypsodont; incisor shorter, more +proödont.</p> + +<p>From <i>B. sawrockensis</i>, <i>B. brachygnathus</i> differs in: molar row slightly +longer; teeth slightly less depressed; masseteric ridge extends farther anteriorly; +incisors more proödont.</p> + +<p>From <i>B. musculus</i>, <i>B. brachygnathus</i> differs in: jaw smaller; molar row +slightly shorter; molars less depressed; incisors slender, shorter, narrower, and +more proödont.</p> + +<p>From <i>B. taylori</i>, <i>B. brachygnathus</i> differs in: incisor more slender, shorter, +more proödont; diastema shorter.</p> +</div> + +<p><i>Remarks.</i>—The molar teeth of <i>B. brachygnathus</i>, although worn, +resemble those of <i>B. taylori</i> more than those of any known fossil +species. Gidley (1922:124) stated that the absence of the divided +anterior lobe of the first molar (anterior median fold) in <i>brachygnathus</i> +was one of the chief characters separating <i>brachygnathus</i> +from <i>taylori</i>. In <i>taylori</i>, the anterior median fold characteristically +is only slightly developed, and in some specimens is absent. <i>B. +brachygnathus</i> differs from <i>taylori</i> chiefly in proödont incisors, which +feature seems to preclude <i>brachygnathus</i> being ancestral to <i>taylori</i>. +<i>B. brachygnathus</i> may have been a specialized divergence from +<i>B. minimus</i>.</p> + + +<div class="caption3"><a name="Baiomys_minimus" id="Baiomys_minimus"></a> +<b>Baiomys minimus</b> (Gidley)</div> + +<div class="species_ref"><i>Peromyscus minimus</i> Gidley, U. S. Geol. Surv. Prof. Papers, 131:124, March +15, 1922.</div> + +<div class="species_ref"><i>Baiomys minimus</i>, Hibbard, Amer. Midland Nat., 26:352, September, 1941; +Gazin, Prof. U. S. Nat. Mus., 92(3155):488, 1942.</div> + +<div class="species_ref"><i>P. [eromyscus] minimus</i>, Wilson, Carnegie Inst. Washington Publ., 473:33, +May 21, 1936.</div> + +<div class="smaller"> +<p><i>Type.</i>—No. 10500, U. S. Nat. Mus.; left mandibular ramus bearing m1-m3 +and incisor; 2 mi. S Benson, sec. 22, T. 17 S, R. 20 E, Late Pliocene (Blancan, +Gazin, 1942:482), Cochise County, Arizona.</p> + +<p><i>Referred material.</i>—None.</p> + +<p><i>Diagnosis.</i>—Ramus small for the genus; molar teeth depressed; cingular +ridges (ectolophids) of m1 and m2 well-developed; anterior median fold present +(appearing larger owing to chip of enamel missing); external reëntrant fold of +m3 progresses half way across crown of tooth; diastema short; incisor moderately +large, recurved; length of molar row, 2.6 mm.</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. brachygnathus</i>, <i>B. kolbi</i>, and <i>B. +sawrockensis</i>, see accounts of those species. From <i>B. rexroadi</i>, <i>B. minimus</i> +<span class="pagenum2"><a name="Page_592" id="Page_592">[Pg 592]</a></span> +differs in: anterior median fold deeper; incisor longer, more recurved, less +proödont; molars slightly more depressed (though worn).</p> + +<p>From <i>B. musculus</i>, <i>B. minimus</i> differs in: over-all size of jaw and molars +smaller; incisors shorter; masseteric ridge more depressed.</p> + +<p>From <i>B. taylori</i>, <i>B. minimus</i> differs in: anterior median fold slightly deeper; +molar teeth more depressed; cingular ridges on m1 and m2 better developed; +masseteric ridge more depressed.</p> +</div> + +<p><i>Remarks.</i>—Gidley (1922:124) stated that <i>B. minimus</i> differed +considerably from <i>B. taylori</i> in that the coronoid portion of the +ascending ramus diverges at a wider angle from the alveolar part of +the jaw. Study of large samples of lower jaws of <i>B. taylori</i> reveals +considerable individual variation in the angle formed between the +coronoid part of the jaw and the alveolar part.</p> + +<p><i>B. minimus</i>, except for its small size, is like <i>B. musculus</i> and is +considered to be ancestral to that species.</p> + + +<div class="caption2"><a name="PHYLETIC_TRENDS" id="PHYLETIC_TRENDS"></a> +PHYLETIC TRENDS</div> + +<p>It seems that the important trends in phyletic development in the +pygmy mice have been from an ancestral stock (see <a href="#fig3">Figure 3</a>) that +possessed relatively brachydont teeth having raised cingular ridges +(ectolophids and mesolophids) and relatively short orthodont to +proödont incisors, to species having teeth more hypsodont on which +cingular ridges were reduced, stylids were isolated or completely +absent, and incisors were longer and more recurved or retrodont. +<i>Baiomys sawrockensis</i>, or an unknown stock resembling it, might +have been ancestral to the other known species. Of the four remaining +fossil species, <i>B. kolbi</i> seems least likely to have been ancestral +to the two living species, owing to its proödont incisors, +reduction of cingular ridges, loss of an anterior median fold in m1, +and long mandibular tooth-row. <i>B. kolbi</i> may have been an early, +specialized derivation from the ancestral stock. From his knowledge +of the habitats of <i>B. musculus</i>, the larger species, and <i>B. +taylori</i>, the smaller species, Hibbard (1952:203) suggests that <i>B. +kolbi</i>, a large species, might have inhabited lowlands, and <i>B. +rexroadi</i>, a small species, highlands. I have no evidence to dispute +this suggestion except that <i>B. musculus</i> has more prominent cingular +ridges (or at least vestiges of this lophid condition) than +either <i>B. kolbi</i> or <i>B. rexroadi</i>. <i>B. musculus</i> (see <a href="#Page_610">page 610</a>) is less +of an open grassland inhabitant than is <i>B. taylori</i>. Therefore, both +<i>B. kolbi</i> and <i>B. rexroadi</i>, because of their poorly developed cingular +ridges, might be expected to have lived in a relatively open +grassland habitat.</p> + +<p><span class="pagenum"><a name="Page_593" id="Page_593">[Pg 593]</a></span></p> + +<p>The relationship of <i>B. rexroadi</i> to fossil species other than <i>B. +kolbi</i> is not clear. Superficially, the former resembles <i>B. taylori</i>, +but, owing to the specialized development of the molars of <i>rexroadi</i>, +it could hardly have been ancestral to either of the living +species. The resemblance of <i>B. rexroadi</i> to <i>B. taylori</i> may result +from each having occupied the same ecological niche in different +periods. The incisors of <i>B. rexroadi</i>, however, are much shorter +than those of <i>B. taylori</i> and suggest somewhat different food habits.</p> + +<p><i>B. minimus</i> seemingly is more closely related to <i>B. sawrockensis</i> +and <i>B. musculus</i> than to the other described species. The development +of the cingular ridges leads one to suspect that <i>B. minimus</i> +was the ancestor of <i>B. musculus</i>. <i>B. minimus</i> may have been derived +from a <i>sawrockensis</i>-like stock and probably gave rise to <i>B. +musculus</i>.</p> + +<p>Hershkovitz (1955:643-644) suggests that "… primitive +brachydont, buno-mesolophodont cricetines have survived … +in forested parts of the range," whereas "… the progressive +branch of cricetines with mesoloph absent or vestigal, has become +increasingly specialized for life in open country and a diet of +grasses." Species of the genus <i>Baiomys</i> can be divided into two +morphological groups. One group, composed of <i>B. sawrockensis</i>, +<i>B. minimus</i>, and <i>B. musculus</i>, includes those species, the teeth of +which were relatively brachydont and had prominently developed +cingular ridges (ectolophids or mesolophids) or, at least, showed +some development of these ridges. <i>B. sawrockensis</i> probably lived +in semi-wooded to shrubby habitats. According to Hibbard (1953:409), +"The Saw Rock Canyon fauna lived in that area at a time +when conditions were comparable to the conditions at the time the +Rexroad fauna lived." The conditions in which the Rexroad fauna +lived are discussed by Hibbard (1941:95). Presumably, there were +at least some well-wooded situations, and the climate was warm. +<i>B. sawrockensis</i> probably inhabited denser vegetation than did <i>B. +minimus</i> or than does <i>B. musculus</i>. The teeth of the second group +(<i>B. kolbi</i>, <i>B. rexroadi</i>, <i>B. brachygnathus</i>, and <i>B. taylori</i>) lack cingular +ridges or have them much reduced and have more hypsodont +molars. The three fossil species probably inhabited relatively open +grassland. This assumption is based largely on the known habitat +of <i>B. taylori</i> (see <a href="#Page_632">page 632</a>).</p> + +<p>The suggested grouping, based on supposed similarities in niches +inhabited by the extinct species, does not necessarily indicate degree +of relationship. <i>B. taylori</i> probably was not derived from an +<span class="pagenum"><a name="Page_594" id="Page_594">[Pg 594]</a></span> +ancestor like <i>B. rexroadi</i> or <i>B. kolbi</i>, although, in certain characters, +the three species resemble one another. <i>B. kolbi</i> and <i>B. rexroadi</i> +were already specialized in Blancan times, probably for living on +grassland. <i>B. taylori</i> shows only a slight advance in specialization +of molar structures compared to either of the aforementioned species +but is slightly smaller and does have longer and more recurved incisors. +If only morphological criteria of lower jaws were considered, +without recourse to other data derived from the study of many +samples of populations of the living species, time alone might account +for the differences among <i>B. taylori</i>, <i>B. rexroadi</i>, and <i>B. kolbi</i>. +The available evidence (see <a href="#Page_658">page 658</a>) suggests, however, that <i>B. +taylori</i> was derived from the <i>B. sawrockensis</i>-<i>B. minimus</i>-<i>B. musculus</i> +line.</p> + +<div class="fig_center"> +<a name="fig3" id="fig3"></a> +<img src="images/fig_3.png" width="578" height="361" alt="" /> +<div class="fig_caption"><span class="smcap">Fig. 3.</span> Diagram indicating probable relationships of living and extinct species +of pygmy mice.</div> +</div> + +<p><i>Baiomys</i> seems to have undergone little basic evolutionary and +morphological change since Late Pliocene time. According to +Simpson (1945:207), hesperomine rodents as a group have undergone +little basic evolution, and "The rapid evolution of new genera +was more a matter of segregation of characters in a group with a +great variation than of the origin of significantly new characters." +Perhaps, the living southern pygmy mouse retains many basic characteristics +of one of the early North American cricetine-like stocks +that emigrated to South America near the end of the Pliocene epoch. +<span class="pagenum"><a name="Page_595" id="Page_595">[Pg 595]</a></span> +There is much to suggest close relationship of the pygmy mice to +certain species of South American hesperomine rodents of the +genus <i>Calomys</i>.</p> + + + + +<div class="caption2"><a name="NON-GEOGRAPHIC_VARIATION" id="NON-GEOGRAPHIC_VARIATION"></a>NON-GEOGRAPHIC VARIATION</div> + + +<p>Non-geographic variation in pygmy mice (variation in a single +population resulting from age, individual, seasonal, and secondary +sexual differences) has been but little studied in the past. Mearns +(1907:381) figured progressive stages of wear on the teeth of +<i>B. taylori</i>; Osgood (1909:252) and Blair (1941:380) referred to +changes in dentition, weights, and pelages.</p> + +<p>The largest samples available for this study were 47 <i>B. taylori</i> from +the vicinity of Altamira (6 mi. N, 6 mi. W; 5 mi. N, 5 mi. W; 1 mi. S), +Tamaulipas, and 44 <i>B. musculus</i> from El Salvador (1 mi. S Los +Planes, and 1 mi. NW San Salvador—two localities 3 miles apart).</p> + + +<div class="caption3"><a name="VARIATION_WITH_AGE" id="VARIATION_WITH_AGE"></a> +VARIATION WITH AGE</div> + +<p>Specimens of both species were segregated into five categories: +Juveniles, young, subadults, adults, and old adults. Juvenal and +young pygmy mice are readily separable from the other three categories; +subadults are less easily distinguished from adults. In order +to obtain an accurate understanding of geographic variation in these +mice, only adults should be used in making taxonomic comparisons.</p> + +<p><i>Juveniles.</i>—Nestling mice yet unweaned; sutures in cranium incompletely +closed; bony parts of skull fragile; M3 and m3 not +erupted or only partly erupted and not protruding above margins +of alveoli.</p> + +<p>At birth, juveniles are pink, without pelage except for the mystacial +vibrissae and a few hairs about the eye. Blair (<i>op. cit.</i>:381) +recorded changes with age in color of the skin of new-born and +suckling pygmy mice. Data obtained by me from three litters born +in captivity agree with his findings. Pygmy mice are weaned when +17 to 24 days old. At that time, the mice possess a fine, but not +dense, dusky-gray fur.</p> + +<p><i>Young.</i>—Weaned mice; cranium fragile; sutures between frontals +and parietals, interparietal and parietals, basioccipital and basisphenoid, +basisphenoid and presphenoid, premaxillaries and maxillaries +widely open; M3 and m3 erupted beyond margins of their +alveoli (molars erupt from anterior to posterior; M3 and m3, therefore, +are last to erupt); in some specimens, molars slightly worn; +pelage still dusky and relatively fine and sparse.</p> + +<p><span class="pagenum"><a name="Page_596" id="Page_596">[Pg 596]</a></span></p> + +<p><i>Subadults.</i>—Sutures between bones of skull less widely open than +in young; epiphyses of long bones incompletely coalesced to shaft; +relative to length of skull, braincase higher and rostrum shorter than +in adults; all cusps worn, but dentine not occlusally confluent; primary +first and second folds of third upper molars present; primary +first fold and major fold of lower molars visible; pelage a subtle +mixture of colors of young and adult, but resembling most that of +adult; molts into postjuvenal pelage between 46 and 50 days.</p> + +<p><i>Adults.</i>—Sutures of skull, and those between epiphyses and shaft +of long bones obliterated except that, in some mice, sutures of skull +persist between frontoparietal, and interparietal; cusps of molars so +worn that dentine occlusally confluent; small island of enamel in +third upper and lower molars of some specimens; relative to length +of skull, cranium lower, rostrum longer, and interorbital region narrower +than in subadult; cranium appears to be more flattened dorsoventrally; +between subadult and adult stages, principal growth +occurs in basioccipital, basisphenoid, frontals, and parietals; nasals +grow less.</p> + +<p>Although all bones of the skull grow in the subadult and early +adult stages (see <a href="#Table_1">table 1</a>), the above-named bones grow faster than +others and thus cause the general flattening of the skull, typical of +adults (similar to that reported by Hoffmeister, 1951:7). The body +continues to lengthen, accounting for the increase in total length +of the adult (see <a href="#Table_1">table 1</a>). Hind foot, tail and ear, reach their +maximum lengths by subadult stage. Adult pelage has been acquired, +and the color is brighter than in either subadults or old +adults.</p> + +<p><i>Old Adults.</i>—Characterized principally by well-worn molars; only +thin peripheral band of enamel along with slight evidence of any +primary or secondary folds on any teeth remain; all bones of skull +coalesced; epiphyses and shafts of long bones ankylosed; small bony +protuberances on many skulls; pelage usually ragged, tips of the +hairs being worn away; white flecking and spotting not common, +but occurs in some adults.</p> + +<div class="center smcap"><a name="Table_1" id="Table_1"></a> +Table 1.—Average and Extreme Measurements (in Millimeters) of Skulls of Five Age-groups<br /> +of Baiomys taylori from vic. (see <a href="#Page_595">p. 595</a>) Altamira, Tamaulipas, Mexico.</div> +<br /> +<table width="80%" style="text-align: center" summary="Skull Dimensions"> +<tr> + <td class="brdtp2 brdbt">Age groups</td> + <td class="brdtp2 brdbt brdlf">Juvenile</td> + <td class="brdtp2 brdbt brdlf">Young</td> + <td class="brdtp2 brdbt brdlf">Subadult</td> + <td class="brdtp2 brdbt brdlf">Adult</td> + <td class="brdtp2 brdbt brdlf">Old adult</td> +</tr> +<tr> + <td class="text_lf">Number examined</td> + <td class="brdlf">3</td> + <td class="brdlf">3</td> + <td class="brdlf">14</td> + <td class="brdlf">19</td> + <td class="brdlf">8</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Total length</td> + <td class="brdlf">77.0<br />(74-79)</td> + <td class="brdlf">92.6<br />(89-96)</td> + <td class="brdlf">97.6<br />(91-103)</td> + <td class="brdlf">99.9<br />(93-105)</td> + <td class="brdlf">101.6<br />(98-107)</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Length of tail</td> + <td class="brdlf">27.3<br />(24-29)</td> + <td class="brdlf">39.3<br />(37-41)</td> + <td class="brdlf">40.4<br />(36-43)</td> + <td class="brdlf">39.8<br />(35-45)</td> + <td class="brdlf">40.9<br />(38-45)</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Length of body</td> + <td class="brdlf">49.6<br />(49-50)</td> + <td class="brdlf">53.3<br />(52-55)</td> + <td class="brdlf">57.0<br />(51-61)</td> + <td class="brdlf">60.0<br />(56-67)</td> + <td class="brdlf">60.7<br />(57-67)</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Length of hind foot</td> + <td class="brdlf">11.0<br />(11)</td> + <td class="brdlf">13.6<br />(13-14)</td> + <td class="brdlf">14.3<br />(13.5-15.0)</td> + <td class="brdlf">14.5<br />(14-15)</td> + <td class="brdlf">14.2<br />(13-15)</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Occipitonasal length</td> + <td class="brdlf">14.2<br />(13.6-15.2)</td> + <td class="brdlf">16.3<br />(15.8-16.9)</td> + <td class="brdlf">17.1<br />(16.7-17.6)</td> + <td class="brdlf">17.7<br />(17.2-18.3)</td> + <td class="brdlf">17.8<br />(17.6-18.1)</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Zygomatic breadth</td> + <td class="brdlf">8.1<br />(7.8- 8.6)</td> + <td class="brdlf">8.7<br />(8.6-8.8)</td> + <td class="brdlf">8.9<br />(8.6-9.3)</td> + <td class="brdlf">9.3<br />(9.0-9.6)</td> + <td class="brdlf">9.4<br />(9.1-9.6)</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Interorbital breadth</td> + <td class="brdlf">3.4<br />(3.3- 3.5)</td> + <td class="brdlf">3.4<br />(3.3-3.6)</td> + <td class="brdlf">3.4<br />(3.3-3.6)</td> + <td class="brdlf">3.6<br />(3.4-3.8)</td> + <td class="brdlf">3.5<br />(3.3-3.6)</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Incisive foramina (length)</td> + <td class="brdlf">2.9<br />(2.8- 2.9)</td> + <td class="brdlf">3.5<br />(3.4-3.6)</td> + <td class="brdlf">3.7<br />(3.6-3.9)</td> + <td class="brdlf">3.9<br />(3.6-4.1)</td> + <td class="brdlf">3.9<br />(3.5-4.0)</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Depth of cranium</td> + <td class="brdlf">5.9<br />(5.6- 6.2)</td> + <td class="brdlf">6.5<br />(6.3-6.8)</td> + <td class="brdlf">6.5<br />(6.2-6.8)</td> + <td class="brdlf">6.7<br />(6.4-7.0)</td> + <td class="brdlf">6.8<br />(6.5-7.1)</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Alveolar length, upper molars</td> + <td class="brdlf">2.7<br />(2.5- 2.8)</td> + <td class="brdlf">2.9<br />(2.9-3.0)</td> + <td class="brdlf">2.9<br />(2.8-3.1)</td> + <td class="brdlf">3.0<br />(2.9-3.2)</td> + <td class="brdlf">3.0<br />(3.0-3.1)</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Postpalatal length</td> + <td class="brdlf">4.8<br />(4.5- 5.3)</td> + <td class="brdlf">5.9<br />(5.8-6.0)</td> + <td class="brdlf">6.2<br />(5.8-6.6)</td> + <td class="brdlf">6.5<br />(6.2-7.2)</td> + <td class="brdlf">6.5<br />(6.3-6.7)</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf brdbt">Breadth of braincase</td> + <td class="brdbt brdlf">8.1<br />(7.8- 8.7)</td> + <td class="brdbt brdlf">8.5<br />(8.5)</td> + <td class="brdbt brdlf">8.4<br />(8.0-8.7)</td> + <td class="brdbt brdlf">8.6<br />(8.3-8.9)</td> + <td class="brdbt brdlf">8.6<br />(8.4-8.8)</td> +</tr> +</table> + +<p><span class="pagenum"><a name="Page_597" id="Page_597">[Pg 597]</a></span></p> + + +<div class="caption3"><a name="SECONDARY_SEXUAL_VARIATION" id="SECONDARY_SEXUAL_VARIATION"></a> +SECONDARY SEXUAL VARIATION</div> + +<p>The method employed by Dice and Leraas (1936:2) was used +to measure the secondary sexual differences, if there were any, in +each of several age classes. As pointed out by Hooper (1952b:11), +individual variation in small samples can obscure secondary sexual +differences. The samples of <i>B. taylori</i> from the vicinity (see page +595) of Altamira, Tamaulipas, and the samples of <i>B. musculus</i> from +El Salvador (<a href="#Table_2">table 2</a>) were large enough to prevent individual +variation from obscuring sexual differences. Nevertheless, no significant +secondary sexual differences were found in either <i>B. taylori</i> +or <i>B. musculus</i> (see <a href="#Table_2">table 2</a>). Therefore, the sexes have been considered +together for purposes of geographic studies.</p> + +<div class="center smcap"><a name="Table_2" id="Table_2"></a> +Table 2.—Analysis of Secondary Sexual Variation in Adult B. taylori Vicinity of (see <a href="#Page_595">p. 595</a>)<br /> +Altamira, Tamaulipas, and Adult B. musculus from El Salvador (see <a href="#Page_595">p. 595</a>).<br /> +(One Standard Deviation on Either Side of the Mean is Given.)</div> +<br /> +<table width="80%" style="text-align: center" summary="Sexual Variation"> +<tr> + <td rowspan="2" class="brdtp2 brdbt">Character</td> + <td colspan="2" class="brdtp2 brdbt brdlf">Baiomys taylori</td> + <td colspan="2" class="brdtp2 brdbt brdlf">Baiomys musculus</td> +</tr> +<tr> + <td class="brdbt brdlf">21 Males</td> + <td class="brdbt brdlf">18 Females</td> + <td class="brdbt brdlf">17 Males</td> + <td class="brdbt brdlf">13 Females</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Total length</td> + <td class="brdlf">98.4 ± 2.95</td> + <td class="brdlf">100.5 ± 4.72</td> + <td class="brdlf">112.04 ± 5.49</td> + <td class="brdlf">113.12 ± 4.23</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Length of tail</td> + <td class="brdlf">40.1 ± 2.31</td> + <td class="brdlf">40.3 ± 2.39</td> + <td class="brdlf">47.12 ± 2.95</td> + <td class="brdlf">45.70 ± 2.92</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Length of body</td> + <td class="brdlf">57.83 ± 1.65</td> + <td class="brdlf">60.10 ± 4.13</td> + <td class="brdlf">66.67 ± 3.97</td> + <td class="brdlf">67.75 ± 2.38</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Length of<br />hind foot</td> + <td class="brdlf">14.21 ± .53</td> + <td class="brdlf">14.44 ± .51</td> + <td class="brdlf">15.60 ± .49</td> + <td class="brdlf">15.38 ± .64</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Length of ear</td> + <td class="brdlf">10.00 ± .00</td> + <td class="brdlf">10.00 ± .00</td> + <td class="brdlf">11.80 ± .65</td> + <td class="brdlf">12.00 ± .41</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Occipitonasal<br />length</td> + <td class="brdlf">17.48 ± .40</td> + <td class="brdlf">17.47 ± .47</td> + <td class="brdlf">19.32 ± .35</td> + <td class="brdlf">19.04 ± .44</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Zygomatic<br />breadth</td> + <td class="brdlf">9.17 ± .33</td> + <td class="brdlf">9.15 ± .30</td> + <td class="brdlf">9.84 ± .21</td> + <td class="brdlf">9.91 ± .28</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Least<br />interorbital<br />breadth</td> + <td class="brdlf">3.53 ± .11</td> + <td class="brdlf">3.48 ± .11</td> + <td class="brdlf">3.88 ± .08</td> + <td class="brdlf">3.88 ± .12</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Postpalatal<br />length</td> + <td class="brdlf">6.35 ± .19</td> + <td class="brdlf">6.38 ± .30</td> + <td class="brdlf">7.11 ± .15</td> + <td class="brdlf">6.95 ± .20</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Depth<br />of cranium</td> + <td class="brdlf">6.65 ± .24</td> + <td class="brdlf">6.61 ± .17</td> + <td class="brdlf">7.10 ± .18</td> + <td class="brdlf">7.08 ± .18</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Incisive<br />foramina<br />(length)</td> + <td class="brdlf">3.82 ± .15</td> + <td class="brdlf">3.81 ± .18</td> + <td class="brdlf">4.43 ± .11</td> + <td class="brdlf">4.35 ± .14</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Length<br />of rostrum</td> + <td class="brdlf">5.87 ± .20</td> + <td class="brdlf">5.88 ± .21</td> + <td class="brdlf">6.81 ± .16</td> + <td class="brdlf">6.66 ± .31</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Breadth<br />of braincase</td> + <td class="brdlf">8.54 ± .23</td> + <td class="brdlf">8.52 ± .12</td> + <td class="brdlf">9.84 ± .38</td> + <td class="brdlf">9.52 ± .20</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="brdbt text_lf">Alveolar<br />length,<br />upper molars</td> + <td class="brdbt brdlf">2.98 ± .08</td> + <td class="brdbt brdlf">3.01 ± .08</td> + <td class="brdbt brdlf">3.20 ± .09</td> + <td class="brdbt brdlf">3.24 ± .10</td> +</tr> +</table> + + +<div class="caption3"><a name="INDIVIDUAL_VARIATION" id="INDIVIDUAL_VARIATION"></a> +INDIVIDUAL VARIATION</div> + +<p>Length of tail varied more than any other measurement used by +me in taxonomic comparisons. Clark (1941:298), Hoffmeister +(1951:16), and Van Gelder (1959:239) point out that external +measurements generally are more variable than measurements of +the cranium, probably because different techniques of measuring +are employed by different collectors. As can be noted in <a href="#Table_3">table 3</a>, +females varied more than males.</p> + +<p><span class="pagenum"><a name="Page_598" id="Page_598">[Pg 598]</a></span></p> + +<p>In the 3520 specimens examined, an extra tooth was observed in +only one (see Hooper, 1955:298). The left mandibular tooth-row +of an adult male (USNM 71539) from Omentepec, Guerrero, is +worn more than the right one. Irregularities in number of teeth +and abnormalities in individual teeth seem to be rare in pygmy +mice.</p> + +<div class="center smcap"><a name="Table_3" id="Table_3"></a> +Table 3.—Individual Variation: Coefficients of Variation for Dimensions of External<br /> +and Cranial Parts in a Population of B. Musculus and B. Taylori.</div> +<br /> +<table width="80%" style="text-align: center" summary="physical variations"> +<tr> + <td class="brdtp2 brdbt" rowspan="3">Measurement</td> + <td class="brdtp2 brdbt brdlf" colspan="2">Baiomys taylori</td> + <td class="brdtp2 brdbt brdlf" colspan="2">Baiomys musculus</td> +</tr> +<tr> + <td class="brdlf" colspan="2">Vic. (see <a href="#Page_595">page 595</a>)<br />Altamira, Tamaulipas</td> + <td class="brdlf" colspan="2">Vic. (see <a href="#Page_595">page 595</a>)<br />El Salvador</td> +</tr> +<tr> + <td class="brdtp brdbt brdlf">21 Males<br />C. V.</td> + <td class="brdtp brdbt brdlf">18 Females<br />C. V.</td> + <td class="brdtp brdbt brdlf">17 Males<br />C. V.</td> + <td class="brdtp brdbt brdlf">13 Females<br />C. V.</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Total length</td> + <td class="brdlf">3.0</td> + <td class="brdlf">4.7</td> + <td class="brdlf">4.9</td> + <td class="brdlf">3.7</td> +</tr> +<tr> + <td class="text_lf">Length of tail</td> + <td class="brdlf">5.7</td> + <td class="brdlf">5.9</td> + <td class="brdlf">6.2</td> + <td class="brdlf">6.4</td> +</tr> +<tr> + <td class="text_lf">Length of body</td> + <td class="brdlf">2.8</td> + <td class="brdlf">5.0</td> + <td class="brdlf">5.9</td> + <td class="brdlf">3.5</td> +</tr> +<tr> + <td class="text_lf">Length of hind foot</td> + <td class="brdlf">3.7</td> + <td class="brdlf">3.4</td> + <td class="brdlf">3.0</td> + <td class="brdlf">4.1</td> +</tr> +<tr> + <td class="text_lf">Length of ear</td> + <td class="brdlf">0.0</td> + <td class="brdlf">0.0</td> + <td class="brdlf">5.5</td> + <td class="brdlf">3.3</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="text_lf">Occipitonasal length</td> + <td class="brdlf">2.2</td> + <td class="brdlf">2.7</td> + <td class="brdlf">1.8</td> + <td class="brdlf">2.3</td> +</tr> +<tr> + <td class="text_lf">Zygomatic breadth</td> + <td class="brdlf">3.6</td> + <td class="brdlf">3.3</td> + <td class="brdlf">2.2</td> + <td class="brdlf">2.7</td> +</tr> +<tr> + <td class="text_lf">Interorbital breadth</td> + <td class="brdlf">3.2</td> + <td class="brdlf">3.3</td> + <td class="brdlf">2.2</td> + <td class="brdlf">2.9</td> +</tr> +<tr> + <td class="text_lf">Incisive foramina<br />(length)</td> + <td class="brdlf">3.8</td> + <td class="brdlf">4.6</td> + <td class="brdlf">2.5</td> + <td class="brdlf">3.2</td> +</tr> +<tr> + <td class="text_lf">Depth of cranium</td> + <td class="brdlf">3.6</td> + <td class="brdlf">2.5</td> + <td class="brdlf">2.5</td> + <td class="brdlf">2.5</td> +</tr> +<tr> + <td class="text_lf">Alveolar length,<br />upper molars</td> + <td class="brdlf">2.7</td> + <td class="brdlf">2.5</td> + <td class="brdlf">2.8</td> + <td class="brdlf">3.2</td> +</tr> +<tr> + <td class="text_lf">Postpalatal length</td> + <td class="brdlf">3.1</td> + <td class="brdlf">4.7</td> + <td class="brdlf">2.1</td> + <td class="brdlf">2.9</td> +</tr> +<tr> + <td class="text_lf">Length of rostrum</td> + <td class="brdlf">3.3</td> + <td class="brdlf">3.6</td> + <td class="brdlf">2.4</td> + <td class="brdlf">4.7</td> +</tr> +<tr> + <td class="text_lf brdbt">Breadth of braincase</td> + <td class="brdbt brdlf">2.7</td> + <td class="brdbt brdlf">1.4</td> + <td class="brdbt brdlf">4.0</td> + <td class="brdbt brdlf">4.9</td> +</tr> +</table> + +<p>The posterior margin of the bony palate varies from semicircular +to nearly V-shaped. The suture between the nasals and frontals +varies from V-shaped to truncate to W-shaped. The maxillary part +of the zygoma varies from broad to slender in dorsoventral width +in both species.</p> + + +<div class="caption3"><a name="PELAGE_AND_MOLTS" id="PELAGE_AND_MOLTS"></a> +PELAGE AND MOLTS</div> + +<p>There are three distinct pelages, juvenal, postjuvenal, and adult. +The sequences of molt and change of pelage from the juvenal, to +the postjuvenal, and from it to adult, are essentially as reported for +<i>Peromyscus</i> by Collins (1918:78-81; 1924:58-60) and Hoffmeister +(1951:5). The juvenal pelage is uniformly dusky gray throughout +except for the paler gray on the venter. In most juvenal mice, the +<span class="pagenum"><a name="Page_599" id="Page_599">[Pg 599]</a></span> +yellow to ochraceous pigments of the subterminal bands are reduced +or absent. Unlike <i>Peromyscus</i>, <i>Baiomys</i> has bright brownish hairs +on the head as the first evidence of the postjuvenal molt (see +<a href="#Table_4">Figure 4, part a</a>). Blair (1941:381) reports adult pelage in pygmy +mice being evident first at an age of 46 days. Two of my juveniles +born in captivity began the postjuvenal molt on the 38th and 40th +days. The area of new hairs on the head spreads most rapidly +posteriorly. New hair appears ventrally and laterally at the end +of 46 days (see <a href="#fig4">Figure 4, part b</a>). Hair replacement proceeds more +slowly after the "saddle back" stage (described in <i>Peromyscus</i> by +Collins, 1918:80) has been reached. That stage was reached in +two pygmy mice at 52 days (see <a href="#fig4">Figure 4, part c</a>). Areas immediately +posterior to the ears, in the scapular region, molt last. The +postjuvenal pelage was seemingly complete in one captive pygmy +mouse at the end of 60 days. Another captive failed to complete +its growth of new pelage until two additional weeks had elapsed. +Length of time required to molt in pygmy mice is about the same +as that reported by Layne (1959:72) in <i>Reithrodontomys</i>.</p> + +<div class="fig_center"> +<a name="fig4" id="fig4"></a> +<img src="images/fig_4.png" width="472" height="454" alt="" /> +<div class="fig_caption"><span class="smcap">Fig. 4.</span> +Diagrams showing progress of the postjuvenal molt in pygmy mice.<br /> +For explanation of a, b, and c, see text. All approximately <sup>2</sup>/<sub>3</sub> natural size.</div> +</div> + +<p><span class="pagenum"><a name="Page_600" id="Page_600">[Pg 600]</a></span></p> + +<p>If, after the postjuvenal molt, a distinct adult pelage is acquired +it is difficult to separate it from the annual replacement of pelage +in adults at the beginning of the rainy season. Adults of both species +have been found in molt in all months of the year. To the north, in +Texas, the pelage of winter-taken specimens is denser and slightly +more reddish than that of specimens taken in spring and summer. +In the two last mentioned seasons, the pelage is more uniformly +gray. To the south, in México, the pelage is heavy and long in +most specimens taken in the rainy season. The percentage of specimens +in molt immediately before the rainy season and immediately +before the dry season is slightly higher than in specimens taken at +other times of the year. The adult or seasonal molt (both loss of +old pelage and growth of new) resembles that in <i>Peromyscus truei +gilberti</i>, described by Hoffmeister (1951:6) as proceeding "posteriorly +as a wave over the entire back." The new hair is slightly +brighter than the old. Old adults are usually in ragged pelage +regardless of season; possibly only one regular annual change of +pelage occurs in most animals before they die. Only one case of +melanism was observed among all the specimens of both species +examined. It was a young male <i>B. t. taylori</i>, KU 35943, from 6 mi. +SW San Gerónimo, Coahuila, possessing black hairs throughout. +Its hairs are longer and finer than those on specimens of comparable +age and sex. No albino was found, although Stickel and Stickel +(1949:145) record one—an adult male of <i>B. taylori</i>.</p> + + +<div class="caption2"><a name="TAXONOMIC_CHARACTERS_AND_RELATIONSHIPS" id="TAXONOMIC_CHARACTERS_AND_RELATIONSHIPS"></a> +TAXONOMIC CHARACTERS AND RELATIONSHIPS</div> + +<p><a name="External_parts" id="External_parts"></a> +<i>External parts.</i>—Length of body, foot, ear, and tail are useful +when considered together in distinguishing species and subspecies. +I found as Hooper (1952a:91) did that length of ear in combination +with length of hind foot suffices to identify nearly all specimens +to species, especially where the two species occur together.</p> + +<p><a name="Pelage" id="Pelage"></a> +<i>Pelage.</i>—Color in adults is of especial value in subspecific determination; +the manner in which it varies geographically is described +on pages 609, 630.</p> + +<p><a name="Skull" id="Skull"></a> +<i>Skull.</i>—Difference in occipitonasal length and zygomatic breadth, +both having low coefficients of variation, are useful in separating +species, especially where they are sympatric. Shape of presphenoid, +nasals, interparietal, frontoparietal sutures, and length and degree +of the openings of the incisive foramina are useful in delimiting +subspecies. The rostrum of <i>B. taylori</i>, in front of the frontonasal +suture, is deflected three to five degrees ventrally in 85 per cent of +<span class="pagenum"><a name="Page_601" id="Page_601">[Pg 601]</a></span> +the adults examined, and in <i>B. musculus</i> is less, or not at all, deflected.</p> + +<p><a name="Teeth" id="Teeth"></a> +<i>Teeth.</i>—Alveolar length of the upper and lower molar tooth-rows +aids in distinguishing fossil and Recent species, and to a lesser degree +in delimiting subspecies. Occlusal pattern is useful in estimating +the relationship of fossil and living species. Degree of +development of the mesostyle, mesostylid, mesoloph, and mesolophid +have been useful in determining relationship between fossil +and living species as well as useful in separating the living species. +Rinker (1954:119) and Hooper (1957:48) have shown the degree +of variation in dental patterns in <i>Peromyscus</i>, <i>Sigmodon</i>, and <i>Oryzomys</i>, +mice thought to be closely related to <i>Baiomys</i>. In pygmy +mice, however, the dental patterns are relatively constant. The +lophs and styles are subject to some geographic variation but, nevertheless, +are useful in estimating relationships.</p> + +<div class="fig_center"> +<a name="fig5" id="fig5"></a> +<img src="images/fig_5.png" width="479" height="342" alt="" /> +<div class="fig_caption"> +<span class="smcap">Fig. 5.</span> Ventral view of hyoid bones. × 18.<br /> +<br /> +A. <i>Baiomys musculus brunneus</i>, adult, female, No. 30182 KU, Potrero Viejo, +1700 feet, Veracruz.<br /> +<br /> +B. <i>Baiomys taylori analogous</i>, adult, female, No. 36761 KU, 2 mi. N Ciudad +Guzmán, 5000 feet, Jalisco.<br /> +</div> +</div> + +<p><a name="Hyoid_apparatus" id="Hyoid_apparatus"></a> +<i>Hyoid apparatus.</i>—Shape and, to a lesser extent, size of the hyoid +apparatus differentiate nearly all specimens of <i>B. taylori</i> from all +those of <i>B. musculus</i>. The hyoid of <i>B. taylori</i> differs from that of +<i>B. musculus</i> principally in the shape of the basihyal. It possesses +<span class="pagenum"><a name="Page_602" id="Page_602">[Pg 602]</a></span> +an anteriorly pointed entoglossal process in <i>B. musculus</i>, and is not +rounded to completely absent as in <i>B. taylori</i> (see <a href="#fig5">Figure 5</a>). The +shoulders of the basihyal protrude anteriorly in <i>B. musculus</i>, and are +not flattened as in <i>B. taylori</i>. The total length was measured in a +sample of 55 basihyals of <i>B. musculus</i>, and was compared to the total +length of a sample of 80 basihyals of <i>B. taylori</i>. The means of the +two samples differ significantly at the 95 per cent level; the mean +plus two standard errors of <i>B. musculus</i> and <i>B. taylori</i>, are, respectively, +2.43 ± .02; 2.18 ± .03. There is sufficient overlap of the +samples (mean plus one standard deviation of <i>B. musculus</i> and <i>B. +taylori</i>, respectively: 2.43 ± .15; 2.18 ± .15) to make the total +length of the basihyal of only secondary importance in distinguishing +species, but shape and total length of the basihyal, when considered +together, serve to identify all specimens to species. When +length of the basihyal is plotted against occipitonasal length (see +<a href="#fig6">Figure 6</a>), all specimens studied, regardless of age or geographical +origin, were separated at the level of species. The hypohyals of +<i>B. taylori</i> seemingly remain distinct throughout life; those of <i>B. +musculus</i> completely fuse in some adults. The ceratohyals are +highly variable in shape and of little taxonomic use.</p> + +<div class="fig_center"> +<a name="fig6" id="fig6"></a> +<img src="images/fig_6.png" width="580" height="373" alt="" /> +<div class="fig_caption"> +<span class="smcap">Fig. 6.</span> Relationship of length of basihyal to occipitonasal length of skull. +Black symbols, all below the curved line, represent measurements of <i>B. taylori</i>; +open symbols, all above the curved line, represent measurements of <i>B. musculus</i>. +</div> +</div> + +<p>The degree of geographic variation in shape of basihyal is not +great. Specimens of <i>B. musculus pallidus</i> from 1 km. NW Chapa, +<span class="pagenum"><a name="Page_603" id="Page_603">[Pg 603]</a></span> +Guerrero, have a small indentation on the anteriormost part of the +entoglossal process. The shoulder of the basihyal is directed less +forward in specimens of <i>B. taylori taylori</i> from 6 mi. N, 6 mi. W +Altamira, Tamaulipas, than in other specimens of the species. The +variations observed seemed not to be clinal.</p> + +<p>According to White (1953:548) the hyoid, like the baculum (Burt, +1936:146), is little influenced by changes in external environment +and may serve to clarify intergeneric relationships. Hyoids of both +species of <i>Baiomys</i> are smaller than hyoids of all subgenera of +<i>Peromyscus</i>. In shape, the hyoids of <i>Baiomys</i> resemble those of +<i>Ochrotomys nuttalli</i> (as explained on <a href="#Page_605">page 605</a>, <i>Ochrotomys</i> is here +accorded generic, instead of subgeneric, rank). In size, the hyoid +of both species of <i>Baiomys</i> resembles that in <i>Reithrodontomys</i>. +Sprague (1941:304) reports a resemblance in shape between the +ceratohyals of <i>Baiomys</i> and <i>Reithrodontomys</i>. The thyrohyals +differ from those of <i>Reithrodontomys</i>, being less boot-shaped, and +having a slight terminal expansion as in <i>Ochrotomys</i> (see Sprague, +<i>loc. cit.</i>). In shape, the large basihyal of <i>Onychomys</i> resembles +the smaller one of <i>B. musculus</i>. The basihyal of <i>Oryzomys</i> lacks +the entoglossal process present in <i>Baiomys</i>. On the basis of shape +of hyoid, <i>Baiomys</i> seems to be most closely related to <i>Ochrotomys</i>.</p> + +<div class="fig_center"> +<a name="fig7" id="fig7"></a> +<img src="images/fig_7.png" width="212" height="271" alt="" /> +<div class="fig_caption"> +<span class="smcap">Fig. 7.</span> Dorsal view of bacula. × 16.<br /> +<br /> +A. <i>B. musculus brunneus</i>, adult, No. +24336 KU, 3 kms. W Boca del Río, +10 feet, Veracruz.<br /> +<br /> +B. <i>B. taylori taylori</i>, adult, No. 35937 +KU, 6 mi. SW San Gerónimo, Coahuila.<br /> +</div> +</div> + +<p><a name="Baculum" id="Baculum"></a> +<i>Baculum.</i>—Of <i>Baiomys</i>, 166 bacula were processed, using the +method of White (1951:125), and studied. They provide characters +of taxonomic worth at the level of species and aid in evaluating +generic relationships.</p> + +<p>The baculum of <i>B. taylori</i> differs from that of <i>B. musculus</i> in: +shaft narrow; wings anterior to base projecting dorsolaterally instead +<span class="pagenum"><a name="Page_604" id="Page_604">[Pg 604]</a></span> +of anteriorly; anterior part knob-shaped having indentation at tip, +instead of anterior part spatulate-shaped (in some) to knob-shaped +(see <a href="#fig7">Figure 7</a>), without indentation; significantly shorter (see +<a href="#Table_4">Table 4</a>).</p> + +<div class="center smcap"><a name="Table_4" id="Table_4"></a> +Table 4.—Length of Bacula</div> +<br /> + +<table width="80%" style="text-align: center" summary="length data"> +<tr> + <td class="brdtp2 brdbt"> </td> + <td class="brdtp2 brdbt brdlf">Number of <br />specimens</td> + <td class="brdtp2 brdbt brdlf">Average <br />length</td> + <td class="brdtp2 brdbt brdlf">3 × <br />standard</td> + <td class="brdtp2 brdbt brdlf">1 <br />standard</td> + <td class="brdtp2 brdbt brdlf">Range</td> +</tr> +<tr> + <td><i>B. taylori</i></td> + <td class="brdlf">108</td> + <td class="brdlf">2.535</td> + <td class="brdlf">.078</td> + <td class="brdlf">.274</td> + <td class="brdlf">2.00-3.12</td> +</tr> +<tr> + <td> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> + <td class="brdlf"> </td> +</tr> +<tr> + <td class="brdbt"><i>B. musculus</i></td> + <td class="brdbt brdlf">58</td> + <td class="brdbt brdlf">3.324</td> + <td class="brdbt brdlf">.090</td> + <td class="brdbt brdlf">.233</td> + <td class="brdbt brdlf">2.80-3.88</td> +</tr> +</table> + +<p>In each of the two species, individual and geographic variation +in the baculum is slight; its length varies insignificantly according +to age. Excluding juveniles contained in <a href="#Table_4">Table 4</a>, but including +young and subadults, only three bacula of <i>B. taylori</i> were longer +than 3 mm., and only one baculum of <i>B. musculus</i> (a young) was +shorter than 3 mm. The total length of the baculum, considered +together with its shape, serves to identify to species all specimens +examined by me.</p> + +<p>The bacula of both species of <i>Baiomys</i> were compared with bacula +of <i>Akodon</i>, <i>Scotinomys</i>, <i>Holochilus</i>, <i>Oryzomys</i>, <i>Zygodontomys</i>, <i>Reithrodontomys</i>, +<i>Thaptomys</i>, and <i>Calomys</i> and illustrations of bacula +by Blair (1942:197, 200) of <i>Peromyscus</i> (subgenera <i>Peromyscus</i>, +<i>Haplomylomys</i>, <i>Podomys</i>), <i>Ochrotomys</i>, and material at the University +of Kansas Museum of Natural History of <i>Megadontomys</i>. +Shape of baculum most resembled that of <i>Ochrotomys</i> and <i>Calomys</i>. +The bacula of <i>Baiomys</i>, as pointed out by Blair (<i>op cit.</i>:203), differ +as much from those of the genus <i>Peromyscus</i> as do the bacula of +<i>Reithrodontomys</i> and <i>Onychomys</i>. In size of baculum, <i>Baiomys</i> +resembles <i>Ochrotomys</i>. Blair (<i>op. cit.</i>:202) pointed out that the +length of the baculum of <i>B. taylori subater</i> was contained in the +length of the animal's body 20.3 times, and 24.2 times in the length +of that of <i>Ochrotomys nuttalli</i>. The length of the baculum of <i>B. +musculus</i> (average of 58 specimens without regard to subspecies) is +contained in the length of the body (of specimens from which the +bacula were removed) 22.7 times, a figure approaching that in +<i>Ochrotomys</i>. When bacula of both species of <i>Baiomys</i> were compared +to those of <i>O. nuttalli</i>, bacula of <i>B. musculus</i> were found to +most closely resemble those of <i>O. nuttalli</i>. The baculum of a single +<span class="pagenum"><a name="Page_605" id="Page_605">[Pg 605]</a></span> +specimen of <i>Calomys</i> (<i>C. laucha</i>) was contained in the length of the +body 15.5 times. In general shape, as well as in possession of an +anterior knob and the position of the expanded posterior wings, the +baculum of <i>C. laucha</i> resembles the baculum of <i>Ochrotomys</i> and +<i>Baiomys musculus</i>.</p> + +<p>Blair (<i>op. cit.</i>:201) considers generic <i>versus</i> subgeneric rank for +<i>Ochrotomys</i>, and on the basis of studies of the phallus Hooper +(1958:23) stated that "it is clear that <i>nuttalli</i> should be removed +from <i>Peromyscus</i> and should be listed as <i>Ochrotomys nuttalli</i> (Harlan)." +I agree with Hooper (<i>loc. cit.</i>) and point out that on the +basis of the baculum, there is less of a hiatus between <i>Baiomys</i> on +the one hand, and <i>Ochrotomys</i> and <i>Calomys</i> on the other hand, +than there is between any one of those three genera and <i>Peromyscus</i>.</p> + +<p>White (1953:631) reported that the baculum of chipmunks might +indicate relationships more clearly than do skulls and skins. He +thought that skulls might more quickly than bacula reflect the +habitus of the animal. The resemblance in cranial morphology +between <i>Peromyscus</i> and <i>Baiomys</i> is judged to be the result of such +a convergence of habitus and the baculum in <i>Baiomys</i> is thought to +reflect relationships more accurately than does the skull.</p> + +<p><a name="Auditory_ossicles" id="Auditory_ossicles"></a> +<i>Auditory ossicles.</i>—Examination of a number of auditory ossicles +of <i>Baiomys</i> reveals constant interspecific differences in the malleus +and incus. There is only slight individual variation, slight variation +with age, and no secondary sexual variation. In <i>Baiomys taylori</i> +the orbicular apophysis of the malleus (see <a href="#fig8">Figure 8, A</a>) is rounded +to nearly ovoid; the anterior process is pointed, and the neck is +short, being slightly recurved. The body of the incus is round and +the short process is elongate. The sides of the long limb of the +incus are nearly parallel. The lenticular process is relatively large. +The posterior and anterior crus of the stapes are bowed, and the +muscular process is either absent or much reduced.</p> + +<p>In <i>Baiomys musculus</i>, the orbicular apophysis of the malleus +(see <a href="#fig8">Figure 8, B</a>) is round to oblong, and less ovoid than in <i>B. +taylori</i>; the anterior process is less acutely pointed than in <i>B. taylori</i>, +and the neck is long, less recurved than in <i>B. taylori</i>. The body of +the incus, though tending to be round, is more flattened, and the +short process is knob-shaped, not elongated. The sides of the long +limb of the incus are not parallel. The lenticular process is, relative +to the size of the incus, small. The posterior and anterior crus +of the stapes are more nearly straight than in <i>taylori</i>. A prominent +muscular process occurs on the posterior crus.</p> + +<p><span class="pagenum"><a name="Page_606" id="Page_606">[Pg 606]</a></span></p> + +<p>The auditory ossicles of representative species of all the subgenera +of <i>Peromyscus</i> were studied as were the ossicles of <i>Onychomys</i>, +<i>Ochrotomys</i>, <i>Oryzomys</i>, <i>Akodon</i>, <i>Thaptomys</i>, <i>Zygodontomys</i>, +<i>Calomys</i>, <i>Reithrodontomys</i>, and <i>Holochilus</i>.</p> + +<div class="fig_center"> +<a name="fig8" id="fig8"></a> +<img src="images/fig_8.png" width="539" height="505" alt="" /> +<div class="fig_caption"> +<span class="smcap">Fig. 8.</span> Lateral views of auditory ossicles. × 20.<br /> +<br /> +A. <i>B. taylori analogous</i>, adult, female, No. 28104 KU, 4 kms. ENE Tlalmanalco, +2290 meters, Estado de México.<br /> +<br /> +B. <i>B. musculus pallidus</i>, adult, male, No. 28346 KU, Cahuilotal, Sacacoyuca, +960 meters, Guerrero.<br /> +</div> +</div> + +<p>The general plan of structure of the auditory ossicles in <i>Baiomys</i> +resembles that in <i>Calomys</i>, <i>Akodon</i>, and <i>Thaptomys</i>. The ossicles +of <i>Calomys</i> and <i>Thaptomys</i>, in particular, closely resemble the auditory +ossicles of <i>Baiomys musculus</i>. The short process of the incus +is knoblike in <i>Calomys</i> and <i>Thaptomys</i>, and the general conformation +of malleus and stapes in those two genera is nearly identical +to that in <i>B. musculus</i>. In <i>Akodon</i>, the anterior and posterior crus +of the stapes is more rounded than in <i>B. musculus</i>, resembling that +in <i>B. taylori</i>.</p> + +<p><span class="pagenum"><a name="Page_607" id="Page_607">[Pg 607]</a></span></p> + +<p><i>Reithrodontomys</i> differ from <i>Baiomys</i> in having a more elongate +orbicular apophysis on the body of the malleus, an elongated short +limb on the incus, and a stapes having anterior and posterior crura +bowed as in mice of the genus <i>Peromyscus</i>.</p> + +<p>In <i>Ochrotomys</i>, the orbicular apophysis of the malleus resembles +the orbicular apophysis of <i>B. musculus</i>, but the short process of the +incus is longer, resembling the short process of <i>B. taylori</i>. In general +conformation of the malleus, incus, and stapes, <i>Ochrotomys</i> +shows closer resemblance to <i>B. taylori</i> than to <i>B. musculus</i>.</p> + +<p>In <i>Holochilus</i> the anterior crus and posterior crus of the stapes +are similar to those in <i>B. musculus</i>, but in shape and size of malleus +and incus, <i>Holochilus</i> differs considerably from <i>B. musculus</i> and +<i>B. taylori</i>.</p> + +<p>In <i>Zygodontomys</i>, size and shape of the ossicles differ greatly +from those of <i>Baiomys</i>.</p> + +<p>In the genus <i>Peromyscus</i>, only <i>Peromyscus floridanus</i> (subgenus +<i>Podomys</i>) possesses a knoblike short process on the incus similar +to that in <i>B. musculus</i>; representatives of the other subgenera examined +possess an elongated short limb on the incus. The conformation +of the ossicles of both <i>Onychomys</i> and <i>Oryzomys</i> appears +to be more nearly like that in <i>Peromyscus</i> than that of <i>Baiomys</i>.</p> + +<p>On the basis of shape and size of auditory ossicles, <i>Baiomys</i> +resembles South American hesperomines (<i>Calomys</i> and <i>Thaptomys</i>) +rather than North American hesperomines.</p> + + +<div class="caption2"><a name="Genus_Baiomys" id="Genus_Baiomys"></a> +Genus <b>Baiomys</b> True</div> + +<div class="species_ref">1894. <i>Baiomys</i> True, Proc. U. S. Nat. Mus., 16:758, February 7. Type, +<i>Hesperomys (Vesperimus) taylori</i> Thomas.</div> + +<p><i>Diagnosis.</i>—Size small (total length in adults, 93-135); tail shorter than +head and body; hind foot in adults 12-17; ears small (8-12) and rounded; +upper parts blackish sepia to ochraceous-buff; underparts slaty gray to white +or pale buffy; eyes small; hind feet having six plantar pads, soles nearly +naked except for some hairs on anterior parts of soles and anteriorly to base +of toes and between toes; occipitonasal length of skull in adults, 17.0-21.5; +zygomatic breadth, 9.0-11.5; coronoid process of mandible well developed, +strongly recurved; ascending ramus of mandible short and erect; anterior +palatine foramina (incisive foramina) long, usually terminating posterior to +plane of the front of first molars; posterior palatine foramina nearly opposite +middle of M2; interorbital space wide relative to widest part of frontals; +nasals projecting only slightly over incisors; condyle terminal; upper incisors +relatively heavy; primary first fold of M3 obliterated at an early stage of wear; +major cusps of upper and lower anteriormost two molars alternating, more so +in m1-m2 than in M1-M2, dental formula I/i, 1/1; C/c, 0/0; P/p, M/m, 3/3 = 16.</p> + +<p>For distribution of the genus, see <a href="#fig9">Figure 9</a>.</p> + +<p><span class="pagenum"><a name="Page_608" id="Page_608">[Pg 608]</a></span></p> + +<div class="fig_center"> +<a name="fig9" id="fig9"></a> +<img src="images/fig_9.png" width="530" height="522" alt="" /> +<div class="fig_caption"> +<span class="smcap">Fig. 9.</span> Geographic distribution of the genus <i>Baiomys</i>. Black area shows where +the two species occur together. Black dot (Acultzingo, Veracruz) shows +locality where <i>Baiomys taylori</i> occurs within the range of <i>B. musculus</i>, but +<i>B. musculus</i> is not known to occur at that locality. +</div> +</div> +<br /> + + +<div class="caption2"><a name="SYSTEMATIC_ACCOUNTS" id="SYSTEMATIC_ACCOUNTS"></a> +SYSTEMATIC ACCOUNT OF SPECIES AND SUBSPECIES</div> + +<div class="caption3"><a name="Baiomys_musculus" id="Baiomys_musculus"></a> +<b>Baiomys musculus</b></div> + +<div class="center">Southern Pygmy Mouse</div> + +<div class="center">(Synonymy under subspecies)</div> + +<div class="species_ref"><i>Type.</i>—<i>Sitomys musculus</i> Merriam, Proc. Biol. Soc. Washington, 7:170, September +29, 1892.</div> + +<div class="smaller"> +<p><i>Range.</i>—Southern Nayarit, Michoacán, México, Morelos, Puebla, and central +Veracruz, southeastward to western Nicaragua, but unknown from southern +Veracruz, Tabasco, and the Yucatán Peninsula (see <a href="#fig10">Figure 10</a>); occurs principally +in the arid upper and lower divisions of the Tropical Life-zone.</p> + +<p><i>Characters for ready recognition.</i>—Unless otherwise noted, characters are +usable only for the two age-categories of adult and old adult. Differs from +<i>B. taylori</i> in: hind foot 16 millimeters or more; occipitonasal length, 19 millimeters +<span class="pagenum2"><a name="Page_609" id="Page_609">[Pg 609]</a></span> +or more; zygomatic breadth, 10 millimeters or more; rostrum not deflected +ventrally at frontoparietal suture but, instead, curving gradually toward +anteriormost point of nasals; cingular ridges and secondary cusps on teeth more +pronounced; basihyal having anterior pointed entoglossal process, shoulders of +basihyal protruding anteriorly (characteristic of all age categories); baculum +having broader shaft, spatulate to knob-shaped tip, wings at base projecting +anteriorly; baculum more than 3 millimeters long; short process of incus knob-shaped +rather than attenuate; muscular process of posterior crus of stapes +prominent.</p> + +<p><i>Characters of the species.</i>—Size large (extremes in external measurements +of adults; total length, 100-135; length of tail vertebrae, 33-56; length of hind +foot, 14.1-17; length of ear, 9-12); upper parts dark reddish brown, or +ochraceous-buff to nearly black; underparts pale pinkish buff to white or pale +buffy.</p> +</div> + +<p><i>Geographic variation.</i>—Eight subspecies are here recognized (see +<a href="#fig10">Figure 10</a>). Features that vary geographically are external size, +color of pelage, certain cranial dimensions (occipitonasal length, +zygomatic breadth, least interorbital breadth, length of rostrum, +length of incisive foramina, depth and breadth of cranium, and +alveolar length of upper molar tooth-row).</p> + +<p>External and cranial size (except for <i>B. m. handleyi</i>) is less in +the southernmost subspecies, <i>B. m. pullus</i>, <i>B. m. grisescens</i>, <i>B. m. +nigrescens</i>, and more in the northernmost subspecies, <i>B. m. musculus</i>, +<i>B. m. brunneus</i>, and <i>B. m. infernatis</i>. Increase in size from south +to north is in keeping with Bergman's Rule that within a species, +smaller individuals occur in warmer parts of its geographic range. +Southern pygmy mice at high altitudes average larger than those +from low elevations, except where the two species are sympatric. +There the Southern Pygmy Mouse is uniformly larger, regardless of +altitude.</p> + +<p>Osgood (1909:257, 259) suggested that degree of relative humidity +might in some way control color of pelage in both <i>B. taylori</i> +and <i>B. musculus</i>. In <i>B. musculus</i>, the darker subspecies, <i>B. m. +brunneus</i>, <i>B. m. nigrescens</i>, and <i>B. m. pullus</i>, occur in zones of rather +constant high relative humidity, whereas the paler subspecies +<i>infernatis</i>, <i>musculus</i>, <i>handleyi</i>, and to a less extent <i>grisescens</i> and +<i>pallidus</i>, occur in zones of lower relative humidity. This is in keeping +with Gloger's Rule, which states that melanins increase in the +warm and humid parts of the range of a species, and reddish or +yellowish-brown phaeomelanins prevail in arid climates. <i>B. m. +musculus</i> ranges into areas where relative humidity is such that +darker pelages might be expected, but this is in the area where the +two species are sympatric, and color of pelage may be an important +character of recognition.</p> + +<p><span class="pagenum"><a name="Page_610" id="Page_610">[Pg 610]</a></span></p> + +<div class="center"> +<a name="fig10" id="fig10"></a> +<img src="images/fig_10.png" width="524" height="596" alt="" /> +<div class="fig_caption center"><span class="smcap">Fig. 10.</span> +Distribution of <i>Baiomys musculus</i>. Known localities of occurrence +are represented by circles and black dots; +the former denote localities that are peripheral (marginal) for the subspecies concerned.<br /> +</div> +<br /> +<table style="text-align:left" summary="species"> +<tr> + <td> + 1. <i>B. m. brunneus</i><br /> + 2. <i>B. m. grisescens</i><br /> + 3. <i>B. m. handleyi</i><br /> + 4. <i>B. m. infernatis</i><br /> + </td> + <td> + + </td> + <td> + 5. <i>B. m. musculus</i><br /> + 6. <i>B. m. nigrescens</i><br /> + 7. <i>B. m. pallidus</i><br /> + 8. <i>B. m. pullus</i><br /> + </td> +</tr> +</table> +</div> + +<div class="caption3"><i>Natural History</i></div> + +<p><i>Habitat and numbers.</i>—In Veracruz, Dalquest obtained the southern +pygmy mouse in stands of tall grass (<i>Spartina?</i>) in sandy loam +soil bordering, and in, dense vegetation; Davis (1944:394) found +the species living in dense stands of grasses and seemingly utilizing +underground burrows. Near Chilpancingo, Guerrero, rocky situations +seemed to be the preferred habitat. Davis (<i>loc. cit.</i>) believed +<span class="pagenum"><a name="Page_611" id="Page_611">[Pg 611]</a></span> +that the species has a wide tolerance to kinds of habitats. In Morelos, +Davis and Russell (1954:75) found these mice to be abundant along +rock fences separating cultivated fields, and in arid lowlands. In +Colima, Hooper (1955b:13) obtained specimens from an open thorn +forest in sparse grass and rocky hillside bounding a stream and in +litter below shrubs on the floor of a nut-palm forest; in Michoacán, +these mice were taken in cane grass, shrubs, and mesquite near an +irrigation ditch. From Guatemala, Goodwin (1934:39, 40) records +specimens from Sacapulas, a hot, dry, sandy area where cactus and +sparse grasses are present, and from La Primavera, on the edges of +pine-oak-alder forests. Felten (1958:137) has taken <i>musculus</i> from +bushy areas in El Salvadore. In 1955, I obtained the southern +pygmy mouse 6 mi. SW Izucár de Matemores, Puebla, along a +stream in heavy grass bordered by cypress, willow, fig, bamboo, and +in rocky grazed area near sugar cane fields.</p> + +<p>The southern pygmy mouse seems to be locally abundant in certain +parts of its geographic range, and in other parts, scarce. For +example, Dalquest (<i>in. litt.</i>) recorded the pygmy mouse as common +at a place 2 km. N Paraje Nuevo, 1700 feet, Veracruz, where, by +means of 50 traps, he took 14 of these mice in one night. The species +was scarcer, although the habitat seemed suitable, 3 km. N Presidio, +1500 feet, Veracruz, where he caught only two pygmy mice in several +days of trapping. Six miles southwest of Izucár de Matemores, the +pygmy mouse was the most common rodent. I have trapped for it +in Oaxaca and Veracruz in habitats that seemed almost identical to +those mentioned by Dalquest, and also that at Izucár de Matemores, +Puebla, with almost no success. The reason for the seeming disparity +in numbers at different localities having nearly the same kind +of habitat is unknown to me and bears further investigation.</p> + +<p><i>Behavior.</i>—Little is recorded concerning the behavior of this +species. David and Russell (<i>op. cit.</i>:76) found that of small mammals +<i>B. musculus</i> was the first to appear at night. I caught mice of +this species by hand in the afternoon in Puebla. They seemed to be +active from noon until dark. Albert Alcorn wrote in his field notes +that specimens were taken near noon at a place 9 mi. NNW Estelí, +Nicaragua. My impression is that <i>musculus</i> is diurnal to crepuscular.</p> + +<p><i>Enemies and food.</i>—Owl pellets (thought to be those of a barn +owl, <i>Tyto alba</i>) from within the geographic range of <i>B. musculus</i>, +from 6 mi. SW Izucár de Matemores, yielded mandibular tooth-rows +belonging to <i>musculus</i>. Presumably, most of the carnivorous mammals +<span class="pagenum"><a name="Page_612" id="Page_612">[Pg 612]</a></span> +and raptorial birds within the range of the southern pygmy +mouse could be listed as enemies. Diurnal to crepuscular habits of +this mouse may protect it from some of the nocturnal carnivorous +mammals and raptorial birds.</p> + +<p>Food of the southern pygmy mouse includes nuts, bark, grass +seeds, and leaves. Dalquest (MS) writes that bits of banana proved +to be useful bait in trapping these mice in Veracruz.</p> + +<p><i>Reproduction.</i>—Notations concerning lactation and embryos on +specimen labels of females suggest that the southern pygmy mouse +breeds in all months. I have records of pregnant or lactating females +in every month, save January, April, May, and June. The average of +26 counts of embryos or young per litter is 2.92 (1-4).</p> + + +<div class="caption3"><a name="Baiomys_musculus_brunneus" id="Baiomys_musculus_brunneus"></a> +<b>Baiomys musculus brunneus</b> (J. A. Allen and Chapman)</div> + +<div class="species_ref"><i>Peromyscus musculus brunneus</i> J. A. Allen and Chapman, Bull. Amer. Mus. +Nat. Hist., 9:203, June 16, 1897; Elliott, Field Columb. Mus. Publ., +105(4):136, July 1, 1905; Elliott, Field Columb. Mus. Publ., 115(8):203, +1907; Osgood, N. Amer. Fauna, 28:259, April 17, 1909.</div> + +<div class="species_ref"><i>Baiomys musculus brunneus</i>, Miller, Bull. U. S. Nat. Mus., 79:137, December +31, 1912; Miller, Bull. U. S. Nat. Mus., 128:318, April 29, 1924; Ellerman, +The Families and Genera of Living Rodents, 2:402, March 21, 1941; +Goldman, Smith. Miscl. Coll., 115:437, July 31, 1951; Goodwin, Bull. +Amer. Mus. Nat. Hist., 102:318, August 31, 1953; Miller and Kellogg, +Bull. U. S. Nat. Mus., 205:512, March 3, 1955; Booth, Walla Walla +Publs., Dept. Biol. Sci., 20:15, July 10, 1957; Hall and Kelson, The +Mammals of North America, 2:661, March 31, 1959 (part).</div> + +<div class="species_ref">[<i>Peromyscus musculus</i>] <i>brunneus</i>, Elliott, Field Columb. Mus. Publ., 95(4): +176, 1904.</div> + +<i>Peromyscus musculus</i> [<i>musculus</i>], Osgood, N. Amer. Fauna, 28:258, April +17, 1909 (part). + +<div class="species_ref"><i>Baiomys musculus musculus</i>, Davis, Jour. Mamm., 25:394, December 12, +1944 (part); Goldman, Smith Miscl. Coll., 115:437, July 31, 1951; +Hooper, Jour. Mamm., 33:97, February 18, 1952 (part); Hall and Kelson, +The Mammals of North America, 2:661, March 31, 1959 (part).</div> + +<div class="species_ref"><i>B.</i> [<i>aiomys</i>] <i>m.</i> [<i>usculus</i>] <i>brunneus</i>, Hooper, Jour. Mamm., 33:96, February +18, 1952.</div> + +<div class="species_ref"><i>Baiomys taylori</i>, Hooper, Jour. Mamm., 33:97, February 18, 1952 (part).</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult female, skin and skull; No. 12535/10845 American Museum +of Natural History; Jalapa, Veracruz, Republic of México; obtained on April +13, 1897, by F. M. Chapman, original number 1203.</p> + +<p><i>Range.</i>—Central Veracruz, coastal plains and eastern slopes of the plateau +of Central México, see <a href="#fig10">Figure 10</a>. Zonal range: Upper Tropical Life-zone +(Lowery and Dalquest, 1951:537), parts of the Veracruz and eastern Transverse +Volcanic biotic provinces of Goldman and Moore (1945:349). Occurs +from near sea level at Boca del Río, Veracruz, up to 5500 feet 3 km. SE +Orizaba.</p> + +<p><i>Diagnosis.</i>—Size medium to large for the species; ground color of dorsum +of paratypes near Olive Brown; darkest of specimens of this subspecies examined +(from Potrero Viejo, Veracruz) between Prouts Brown and Mummy +<span class="pagenum2"><a name="Page_613" id="Page_613">[Pg 613]</a></span> +Brown; distal two-thirds of guard hairs of dorsum black, proximal third dark +gray to sooty; hairs of dorsum black-tipped having subterminal band of +Ochraceous-Tawny; sides paler (less of dark brown) than dorsum; venter Deep +Olive Buff to clay color, individual hairs pale olive buff at tips, dark gray +basally; region of throat and chin sooty gray; ventralmost vibrissae white to +base, other vibrissae black to base; ears dark brown, sparsely haired; forefeet and +hind feet flesh-colored in palest specimens, sooty in darkest; tail pale brown, +slightly paler below than above; presphenoid only slightly constricted towards +midline; average and extreme external and cranial measurements of 10 adults +from Cerro Gordo, Veracruz, are as follows: total length, 118.9 (112-127); +length of tail vertebrae, 45.1 (42-50); length of body, 74.0 (69-78); length +of hind foot, 16.0 (16); length of ear from notch, 12.8 (12-13); occipitonasal +length, 19.5 (19.0-20.0); zygomatic breadth, 10.3 (10.0-10.8); postpalatal +length, 7.1 (6.7-7.5); least interorbital breadth, 3.9 (3.7-4.0); length of +incisive foramina, 4.4 (4.1-4.6); length of rostrum, 6.9 (6.5-7.2); breadth of +braincase, 9.5 (9.2-9.7); depth of cranium, 7.1 (7.1-7.4); alveolar length of +maxillary tooth-row, 3.3 (3.2-3.3); for photographs of skull, see <a href="#plate1">Plate 1<i>a</i></a>, and +<a href="#plate3">Plate 3<i>a</i></a>.</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. m. nigrescens</i>, see account of that +subspecies. From <i>B. m. pallidus</i>, <i>B. m. brunneus</i> differs in: dorsal, lateral, +and facial coloration deeper reddish brown, more melanins present; venter +darker; buff gray rather than whitish buff to gray as in paratypical series; +vibrissae black rather than brownish to white; tail sooty, less flesh-colored; +forefeet and hind feet averaging slightly grayer; most external and cranial +dimensions averaging slightly larger; nasals less attenuated; presphenoid less +hour-glass shaped, sides more nearly straight.</p> + +<p>From <i>B. m. infernatis</i>, <i>B. m. brunneus</i> differs in: side of face and neck +deep reddish-brown rather than yellowish-gray (the differences in dorsal +colorations are greater between <i>brunneus</i> and <i>infernatis</i> than between <i>brunneus</i> +and <i>pallidus</i>); venter darker buff-gray; tail brownish rather than flesh-colored; +forefeet and hind feet average slightly grayer; most external dimensions averaging +slightly larger; cranial dimensions nearly the same except length of +incisive foramina, which is smaller; presphenoid differs in much the same way +as from pallidus.</p> +</div> + +<p><i>Remarks</i>.—Specimens from Chichicaxtle, Puente Nacional, 3 km. +W Boca del Río, 1 km. E. Mecayucan, and Río Blanco (20 km. +WNW Piedras Negras), are all paler than the paratypical series and +other specimens from within the assigned range of <i>B. m. brunneus</i>. +All these specimens from the coastal plain average considerably +paler than those from the front range and slopes of the mountains. +Specimens from Puente Nacional are intermediate in color between +paler, grayish brown, specimens from the coastal plains and the +darker, brown, specimens from the mountains. When Allen and +Chapman (1897:203) described <i>brunneus</i>, they did so on the basis +of the darker brown mice from the higher altitudes. The name, +<i>brunneus</i>, <i>sensu stricto</i>, could be restricted to those mice from the +<span class="pagenum"><a name="Page_614" id="Page_614">[Pg 614]</a></span> +higher altitudes of central Veracruz. However, when the mice of +intermediate color from Puente Nacional are considered, it seems +best to include the material from the coastal plain with <i>brunneus</i>. +Crania from the higher altitudes are slightly larger than, but not +significantly different from, crania of specimens from the coastal +plains. Specimens examined from the coastal plains resemble the +darker series of <i>B. m. pallidus</i> to the west in central México. But +there is no evidence of gene flow between the paler coastal specimens +and <i>B. m. pallidus</i> to the west. In fact, these paler brown mice +on the coastal plain grade in color into the darker brown mice from +the mountains. The paler mice from the coast may be an incipient +subspecies.</p> + +<p>The type and paratypes seem to have faded somewhat since they +were described by Allen and Chapman (<i>loc. cit.</i>) and by Osgood +(1909:259). However, the color of the paratypes and other specimens +herein assigned is the feature most useful for distinguishing +<i>brunneus</i> from all other subspecies of <i>B. musculus</i>.</p> + +<div class="smaller"> +<a name="FNanchor_1_1" id="FNanchor_1_1"></a> +<a name="FNanchor_2_2" id="FNanchor_2_2"></a> +<a name="FNanchor_3_3" id="FNanchor_3_3"></a> +<a name="FNanchor_4_4" id="FNanchor_4_4"></a> +<a name="FNanchor_5_5" id="FNanchor_5_5"></a> +<a name="FNanchor_6_6" id="FNanchor_6_6"></a> +<p><i>Specimens examined.</i>—Total 187 all from <span class="smcap">Veracruz</span>, Republic of México, +and distributed as follows: type locality, 4400 ft., 16<a href="#Footnote_1_1" class="fnanchor">[1]</a> +(including the type), 6<a href="#Footnote_2_2" class="fnanchor">[2]</a>, +1<a href="#Footnote_3_3" class="fnanchor">[3]</a>; <i>Cerro Gordo</i>, 1500 ft., 19; +<i>Teocelo</i> [= <i>Texolo</i>], 4500 ft., 1; <i>2 mi. NW Plan del Río</i>, 1000 ft., 14<a href="#Footnote_4_4" class="fnanchor">[4]</a>; +<i>Plan del Río</i>, 1000 ft., 2<a href="#Footnote_5_5" class="fnanchor">[5]</a>; +<i>Carrizal</i>, 4<a href="#Footnote_2_2" class="fnanchor">[2]</a>; Chichicaxtle, 3<a href="#Footnote_2_2" class="fnanchor">[2]</a>; +<i>Puente Nacional</i>, 500 ft., 1<a href="#Footnote_5_5" class="fnanchor">[5]</a>, 2; +<i>Santa Maria, near Mirador</i>, 1800 ft., 10<a href="#Footnote_2_2" class="fnanchor">[2]</a>; +Boca del Río, 10 ft., 1<a href="#Footnote_5_5" class="fnanchor">[5]</a>, 8; +<i>Córdoba</i> [= <i>Córdova</i>], 14<a href="#Footnote_1_1" class="fnanchor">[1]</a>; <i>4 km. WNW Fortín</i>, 4; +<i>Río Atoyac, 8 km. NW Potrero</i>, 1; <i>2 km. N. Paraje Nuevo</i>, 1700 ft., 9; +<i>El Xuchil</i>, <i>1 mi. W. Paraje Nuevo</i>, 6<a href="#Footnote_6_6" class="fnanchor">[6]</a>; +Potrero Viejo, 1700 ft. 15; <i>Cautlapán</i> [= <i>Ixtaczequitlán</i>], 4000 ft., 16; <i>Micayucan</i>, 1; +3 km. SE Orizaba, 5500 ft., 3; Río Blanco, 20 km. WNW Piedras Negras, 400 ft, 7; +<i>29 km. SE Córdoba, Presidio</i>, 15<a href="#Footnote_4_4" class="fnanchor">[4]</a>; <i>3 km. N Presidio</i>, 1500 ft., 2; +Presidio, 600 meters, 6<a href="#Footnote_3_3" class="fnanchor">[3]</a>.</p> + +<p><i>Marginal records.</i>—<span class="smcap">Veracruz</span>: type locality; Chichicaxtle; Boca del Río, +10 ft.; Río Blanco, 20 km. WNW Piedras Negras, 400 ft; Presidio; 3 km. SE +Orizaba, 5500 ft.</p> +</div> + +<div class="footnote"><p><a name="Footnote_1_1" id="Footnote_1_1"></a> +<a href="#FNanchor_1_1"><span class="label">[1]</span></a> American Museum of Natural History.</p></div> + +<div class="footnote"><p><a name="Footnote_2_2" id="Footnote_2_2"></a> +<a href="#FNanchor_2_2"><span class="label">[2]</span></a> U. S. Nat. Museum (Biol. Surv. Coll.).</p></div> + +<div class="footnote"><p><a name="Footnote_3_3" id="Footnote_3_3"></a> +<a href="#FNanchor_3_3"><span class="label">[3]</span></a> Chicago Natural History Museum.</p></div> + +<div class="footnote"><p><a name="Footnote_4_4" id="Footnote_4_4"></a> +<a href="#FNanchor_4_4"><span class="label">[4]</span></a> Univ. Michigan, Museum of Zoology.</p></div> + +<div class="footnote"><p><a name="Footnote_5_5" id="Footnote_5_5"></a> +<a href="#FNanchor_5_5"><span class="label">[5]</span></a> Texas A & M, Coop. Wildlife Res. Coll.</p></div> + +<div class="footnote"><p><a name="Footnote_6_6" id="Footnote_6_6"></a> +<a href="#FNanchor_6_6"><span class="label">[6]</span></a> Univ. Illinois, Mus. Nat. History.</p></div> + + +<div class="caption3"><a name="Baiomys_musculus_grisescens" id="Baiomys_musculus_grisescens"></a> +<b>Baiomys musculus grisescens</b> Goldman</div> + +<div class="species_ref"><i>Baiomys musculus griesescens</i> Goldman, Proc. Biol. Soc. Washington, 45:121, +July 30, 1932; Ellerman, The Families and Genera of Living Rodents, +2:402, March 21, 1941; Poole and Schantz, Bull. U. S. Nat. Mus., 178:259, +March 6, 1942; Goodwin, Bull. Amer. Mus. Nat. Hist., 79(2):160-161, +May 29, 1942 (part); Miller and Kellogg, Bull. U. S. Nat. Mus., 205:513, +March 3, 1955 (part); Felten, Senck. Biol., 39:136, August 30, 1958; +Packard, Univ. Kansas Publs., Mus. Nat. Hist., 9:401, December 19, +1958; Hall and Kelson, The Mammals of North America, 2:661, March +31, 1959 (part).</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult female, skin and skull; No. 257083 U. S. Nat. Mus. (Biol. +Surv. Coll.); Comayabuela [= Comayaguela] just south of Tegucigalpa, 3100 +feet, Honduras; obtained on March 6, 1932, by C. F. Underwood, original +number 838.</p> + +<p><span class="pagenum2"><a name="Page_615" id="Page_615">[Pg 615]</a></span></p> + +<p><i>Range.</i>—Central to south-central Guatemala, east to south-central Honduras. +Zonal range: Lower parts of the Merendon Biotic Province of Smith (1949:235). +Occurs from 3200 feet at a place <sup>1</sup>/<sub>2</sub> mi. N and 1 mi. W Salama, Guatemala, up +to approximately 4500 feet at Monte Redondo, Guatemala.</p> + +<p><i>Diagnosis.</i>—Size medium to small for the species; general ground color of +dorsum between Olive Brown and Buffy Brown; distal fourth of individual +guard hairs of dorsum black-tipped, proximal three-fourths gray, underfur +black-tipped with subterminal band of Vinaceous-Buff, gray basally; facial +region below eye Olive-Buff to Deep Olive-Buff; regions of flanks without +black-tipped guard hairs, therefore, appearing paler brownish-buff than dorsum; +venter Pale Olive-Buff to whitish in midline, hairs there white to base, laterally +grayish basally; hairs in region of throat and chin resemble those of underparts; +forefeet and hind feet flesh-colored with grayish suffusion; ears dusky +brown; tail almost unicolored, slightly darker brown above than below; coronoid +process less acutely falcate than in other subspecies; zygoma bowed. Average +and extreme external and cranial measurements of 14 adults from La Piedra +de Jesús Sabana Grande, Honduras, are as follows: Total length, 110.7 +(100-123); length of tail vertebrae, 44.0 (32-55); length of body, 66.7 (60-70); +length of hind foot, 14.1 (12-15); length of ear from notch, 11.8 (10-13); +occipitonasal length, 19.3 (18.9-19.8); zygomatic breadth, 10.1 (9.8-10.4); +postpalatal length, 6.8 (6.2-7.3); least interorbital breadth, 3.9 (3.8-4.1); +length of incisive foramina, 4.3 (4.0-4.5); length of rostrum, 6.9 (6.6-7.2); +breadth of braincase, 9.6 (9.2-10.1); depth of cranium, 7.0 (6.8-7.3); alveolar +length of maxillary tooth-row, 3.2 (3.0-3.4); for photographs of skull, see +<a href="#plate1">Plate 1<i>b</i></a>, and <a href="#plate3">Plate 3<i>b</i></a>.</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. m. pullus</i> and <i>B. m. handleyi</i>, see +accounts of those subspecies. From <i>B. m. nigrescens</i>, <i>B. m. grisescens</i> differs +in: dorsum less blackish (dark brown to buffy); face buffy below eye rather +than brownish-black; venter buffy to whitish in midline, not sooty gray; forefeet +and hind feet flesh-colored with gray overtones, not dusky to sooty; +zygoma bowed, sides less parallel; braincase and bony palate slightly broader.</p> +</div> + +<p><i>Remarks.</i>—Goodwin (1942:160) mentioned that a specimen from +the type locality of <i>grisescens</i> was as dark as specimens of <i>B. m. +nigrescens</i> from Guatemala. However, all specimens from Guatemala, +other than those from Sacapulas, were referred by Goodwin +(1934:40) to <i>B. m. nigrescens</i>. My studies reveal a grayish-brown +population in central Honduras near to and including the type +locality. This population appears to grade into a slightly paler, +particularly as concerns color of hind foot and tail, group of Guatemalan +mice from 1 mi. S Rabinal, from <sup>1</sup>/<sub>2</sub> mi. N, 1 mi. E Salama, and +from Lake Atescatempa. Specimens from western Guatemala at +Nentón and Jacaltenango, on the other hand, are darker brownish-black, +more nearly like the paratypical series of <i>nigrescens</i> from the +Valley of Comitán, Chiapas, Republic of México. This darker +brownish-black color of the back persists in specimens from southern +<span class="pagenum"><a name="Page_616" id="Page_616">[Pg 616]</a></span> +Guatemala and El Salvador (see specimens examined of <i>B. m. +nigrescens</i> for localities), and they are best referred to <i>nigrescens</i>. +<i>B. m. grisescens</i>, in color and certain cranial characters, therefore, +seems to grade into two different subspecies: (1) <i>B. m. handleyi</i>, +pale mice in the Río Negro valley in central Guatemala, and (2) +<i>B. m. nigrescens</i>, dark mice from southern Guatemala, and parts of +El Salvador.</p> + +<p>Felten (1958:136) referred all <i>B. musculus</i> from El Salvador to +<i>B. m. grisescens</i>. Although I have not examined the specimens +reported on by Felten (<i>loc. cit.</i>), I have examined specimens from +Lake Atescatempa, Guatemala (which I refer to <i>grisescens</i>), not +too distant from Cerro Blanco, and Finca Las Canarias, Department +of Ahuachapan, and Laguna de Guija, Department of Santa Ana +(localities listed by Felten). It would seem that specimens from +these localities might indeed be <i>grisescens</i>. However, specimens +that I examined from 1 mi. S Los Planes, and 1 mi. NW San +Salvador were considerably darker than paratypes of <i>grisescens</i> +and were nearly intermediate in color between <i>nigrescens</i> and +<i>pullus</i>. I refer the specimens from 1 mi. NW San Salvador, and 1 +mi. S Los Planes to <i>nigrescens</i> rather than to <i>grisescens</i>.</p> + +<p>There is no positive evidence that <i>B. m. grisescens</i> intergrades +with <i>B. m. pullus</i> to the south in Nicaragua. But, there is a suggestion +that intergradation occurs between these subspecies in a +series of 76 skins from La Piedra de Jesús Sabana Grande, Honduras, +referable to <i>grisescens</i>. A total of 16 of 76 skins from this locality +(21 per cent) possess the mid-ventral white stripe found in 18 +of 20 skins (90 per cent), from the type locality of <i>pullus</i> in +Nicaragua. Further collection in areas between central Honduras +and western Nicaragua may yield specimens of <i>B. musculus</i> that +are intermediate in characters between <i>grisescens</i> and <i>pullus</i>.</p> + +<div class="smaller"> +<a name="FNanchor_1_7" id="FNanchor_1_7"></a> +<a name="FNanchor_2_8" id="FNanchor_2_8"></a> +<a name="FNanchor_3_9" id="FNanchor_3_9"></a> +<p><i>Specimens examined</i>.—Total 149, distributed as follows: +<span class="smcap">Guatemala</span>: 1 mi. S Rabinal, 3450 ft., 14; <sup>1</sup>/<sub>2</sub> mi. N, 1 mi. E Salama, 3200 ft., 10; +Lake Atescatempa, 10<a href="#Footnote_1_7" class="fnanchor">[7]</a>. +<span class="smcap">Honduras</span>: Cementario, Gracias, 1<a href="#Footnote_2_8" class="fnanchor">[8]</a>; +Monte Redondo, 1<a href="#Footnote_2_8" class="fnanchor">[8]</a>; +El Caliche, Cedros, 1<a href="#Footnote_2_8" class="fnanchor">[8]</a>; +<i>La Flor Archaga</i>, 2<a href="#Footnote_2_8" class="fnanchor">[8]</a>, 1<a href="#Footnote_3_9" class="fnanchor">[9]</a>; +Hatillo, 1<a href="#Footnote_2_8" class="fnanchor">[8]</a>; +<i>type locality</i>, 7<a href="#Footnote_2_8" class="fnanchor">[8]</a>, +6<a href="#Footnote_1_7" class="fnanchor">[7]</a> (including the type), +3<a href="#Footnote_3_9" class="fnanchor">[9]</a>; +<i>El Zapote</i>, <i>Sabana Grande</i>, 4<a href="#Footnote_2_8" class="fnanchor">[8]</a>; +La Piedra de Jesús Sabana Grande, 76<a href="#Footnote_2_8" class="fnanchor">[8]</a>; +<i>Cerro de las Cuches Sabana Grande</i>, 5.</p> + +<p><i>Marginal records.</i>—<span class="smcap">Guatemala</span>: <sup>1</sup>/<sub>2</sub> mi. N, 1 mi. E Salama, 3200 ft. +<span class="smcap">Honduras</span>: El Caliche, Cedros; Hatillo; La Piedra de Jesús Sabana Grande; Cementario. +<span class="smcap">Guatemala</span>: Lake Atescatempa; 1 mi. S Rabinal, 3450 ft.</p> +</div> + +<div class="footnote"><p><a name="Footnote_1_7" id="Footnote_1_7"></a> +<a href="#FNanchor_1_7"><span class="label">[7]</span></a> United States National Museum +(Biol. Surv. Collections).</p></div> + +<div class="footnote"><p><a name="Footnote_2_8" id="Footnote_2_8"></a> +<a href="#FNanchor_2_8"><span class="label">[8]</span></a> American Museum of Natural History.</p></div> + +<div class="footnote"><p><a name="Footnote_3_9" id="Footnote_3_9"></a> +<a href="#FNanchor_3_9"><span class="label">[9]</span></a> Univ. Michigan, Museum of Zoology.</p> + +<p><span class="pagenum"><a name="Page_617" id="Page_617">[Pg 617]</a></span></p></div> + + +<div class="caption3"><a name="Baiomys_musculus_handleyi" id="Baiomys_musculus_handleyi"></a> +<b>Baiomys musculus handleyi</b> Packard</div> + +<div class="species_ref"><i>Baiomys musculus handleyi</i> Packard, Univ. Kansas Publs., Mus. Nat. Hist., +9:399, December 19, 1958.</div> + +<div class="species_ref"><i>Baiomys musculus musculus</i>, Goodwin, Bull. Amer. Mus. Nat. Hist., 68(1):39-40, +December 12, 1934 (part); Miller and Kellogg, Bull. U. S. +Nat. Mus., 205:512, March 3, 1955 (part).</div> + +<div class="species_ref"><i>Baiomys musculus nigrescens</i>, Hall and Kelson, The Mammals of North +America, 2:661, March 31, 1959 (part).</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult female, skin and skull; No. 275604 U. S. Nat. Mus. (Biol. +Surv. Coll.); Sacapulas, El Quiche, Guatemala; obtained on April 24, 1947, by +Charles O. Handley, Jr., original number 991.</p> + +<p><i>Range.</i>—Known only from the type locality in the valley of the Río Negro. +Zonal range: Part of the Chimaltenangan Province of Smith (1949:235).</p> + +<p><i>Diagnosis.</i>—Size medium to large for the species; dorsum Wood Brown in +some series to Buffy Brown; guard hairs of dorsum black-tipped, color of underhairs +Avellaneous; hairs white to base in region of chin, throat, and median +venter; in lateral region, hairs Neutral Gray at base; dorsal surfaces of forefeet +and hind feet and ankles white; tail white below, brownish above; nasals +truncate anteriorly; frontoparietal suture forming an obtuse angle with the +suture separating the parietals; alveolar length of upper molar tooth-row and +tail long. Average and extreme external and cranial measurements for nine +adults from the type locality are as follows: Total length, 121.4 (115-128); +length of tail vertebrae, 50.7 (49-54); length of body, 70.8 (66-77); length of +hind foot, 15.3 (15-16); occipitonasal length, 19.6 (18.8-20.7); zygomatic +breadth, 10.5 (10.2-11.0); postpalatal length, 6.9 (6.4-7.4); least interorbital +breadth, 4.0 (3.9-4.0); length of incisive foramina, 4.2 (4.0-4.5); length of +rostrum, 7.2 (7.0-7.7); breadth of braincase, 9.8 (9.7-10.2); depth of cranium, +7.1 (6.8-7.2); alveolar length of maxillary tooth-row, 3.5 (3.4-3.6); for photographs +of skull, see <a href="#plate1">Plate 1<i>c</i></a>, and <a href="#plate3">Plate 3<i>c</i></a>.</p> + +<p><i>Comparisons.</i>—From <i>B. m. nigrescens</i>, <i>B. m. handleyi</i> differs as follows: +everywhere paler; forefeet and hind feet whitish instead of dusky to sooty; +hairs of anterior part of face white instead of brown; tail bicolored instead of +unicolored; anterior tips of nasals truncate rather than rounded; frontoparietal +suture forming obtuse angle with suture separating parietals instead of forming +right angle; tail and upper molar tooth-row longer.</p> + +<p>From <i>B. m. grisescens</i>, <i>B. m. handleyi</i> differs in: slightly paler above and +below, primarily as a result of lacking buff-colored hairs; forefeet and hind feet +white, not flesh-colored with gray overtones; tail bicolored, not unicolored; +anterior tips of nasals truncate rather than flaring; tail and upper molar tooth-row +longer.</p> +</div> + +<p><i>Remarks.</i>—<i>B. m. handleyi</i> seems to be restricted to the valley of +the Río Negro, in the region of Sacapulas, Guatemala. Stuart +(1954:7) points out that the Río Negro drops down into a gorge at +a place near Sacapulas and flows northward through a deep canyon +<span class="pagenum"><a name="Page_618" id="Page_618">[Pg 618]</a></span> +for approximately 60 kilometers. The Río Negro, then, flows onto +the lowlands of the Yucatán Peninsula. The habitat is xerophytic +in the valley of the Río Negro near Sacapulas. Stuart (<i>op. cit.</i>:10) +suggests that this xerophytic habitat may be continuous to a place +to the north of Chixoy, Chiapas, where the vegetation then becomes +more mesic. The mesic conditions to the north in Tabasco +and Yucatán probably have restricted the movement of pygmy mice +to the north. No specimens of this mouse are known from the +Yucatán Peninsula or from the State of Tabasco, México. <i>B. m. +handleyi</i> intergrades with <i>B. m. grisescens</i> to the south. Specimens +from 1 mi. S Rabinal, and those from a second locality <sup>1</sup>/<sub>2</sub> mi. N and +1 mi. E Salama, Guatemala, are intermediate in color of pelage between +<i>handleyi</i> and <i>grisescens</i>. Stuart (<i>op. cit.</i>:5) mentions the +continuity of habitat and tributaries from the Salama Basin into the +valley of the Río Negro. Absence of physiographic and biotic barriers +in the corridor between these two basins probably allows for +some gene flow between <i>handleyi</i> and <i>grisescens</i>, and results in +populations intermediate in color. To the north and northwest of +Sacapulas, the Sierra de los Cuchumatanes rises abruptly and separates +the known geographic range of <i>handleyi</i> from that of <i>nigrescens</i> +to the north, while to the west the cactus-mesquite habitat of +<i>handleyi</i> gives way to the oak-pine timber that, so far as known, +does not support <i>Baiomys</i>. The difference in elevation and flora +seems to restrict gene flow between <i>handleyi</i> and the more northern +<i>nigrescens</i>. The only evidence of integration between these two +subspecies is provided by one specimen from Chanquejelve, Guatemala. +That specimen is intermediate in color between the pale +<i>handleyi</i> and blackish-brown <i>nigrescens</i>.</p> + +<p>The subspecies closest, geographically, to <i>B. m. handleyi</i> is <i>B. m. +nigrescens</i>, from which <i>B. m. handleyi</i> differs more in color than +from any of the other named subspecies, except <i>B. m. pullus</i>. There +is a close correlation of pallor of mice and the xeric Río Negro Valley, +and the darkness (melanistic color) of mice and the mesic +mountains and valleys to the north.</p> + +<div class="smaller"> +<p><i>Specimens examined.</i>—Total 49, from <span class="smcap">Guatemala</span>: type locality, including +the type: 12 (U. S. Nat. Mus., Biol. Surv. Coll.), 37 (Amer. Mus. Nat. Hist.).</p> +</div> + + +<div class="caption3"><a name="Baiomys_musculus_infernatis" id="Baiomys_musculus_infernatis"></a> +<b>Baiomys musculus infernatis</b> Hooper</div> + +<div class="species_ref"><i>Baiomys musculus infernatis</i> Hooper, Jour. Mamm., 33:96, February 18, +1952; Miller and Kellogg, Bull. U. S. Nat. Mus., 205:512, March 3, 1955; +Hall and Kelson, The Mammals of North America, 2:661, March 31, +1959.</div> + +<div class="species_ref"><i>Baiomys musculus musculus</i>, Hooper, Jour. Mamm., 28:50, February 15, +1947 (part).</div> + +<p><span class="pagenum"><a name="Page_619" id="Page_619">[Pg 619]</a></span></p> + +<div class="smaller"> +<p><i>Type.</i>—Adult male, skin and skull; No. 91497 Univ. of Michigan, Museum +of Zoology; Teotitlán, Oaxaca, Republic of México, obtained on February 24, +1947, by Helmuth O. Wagner, original number 2702.</p> + +<p><i>Range.</i>—Southeastern Puebla, in the basin drained by the Río Salado and +Río Quiotepec, into northern Oaxaca. Zonal range: Arid Tropical in a part +of the Orizaba-Zempoaltepec Faunal District of the Transverse Volcanic Biotic +Province of Moore (1945:218). Occurs from 3100 feet in Oaxaca up to 6000 +feet in Puebla.</p> + +<p><i>Diagnosis.</i>—Size medium for the species; dorsum Drab, terminal parts of +individual guard hairs black, Neutral Gray basally, distal parts of underfur +Pinkish Buff, proximally Neutral Gray; sides same color as dorsum; hairs in +region of throat and chin white to base; venter whitish to Neutral Gray with +tinges of Pinkish Buff; dorsal parts of forefeet and hind feet whitish with +flesh-colored undertones, ventral parts whitish to dusky-gray; tail bicolored, +grayish-brown above, white below; tip of tail not bicolored, instead grayish-brown +throughout; ears pale brown, sparsely haired; incisive foramina long, +not constricted posteriorly. Average and extreme external measurements for +9 adults from the type locality are as follows: total length, 113.9 (106-122); +length of tail vertebrae, 44.1 (41-48); length of body, 71.0 (65-79); length +of hind foot, 14.8 (13-16); length of ear, 11.9 (11-12). Average and extreme +cranial measurements of 7 adults from the type locality are as follows: Occipitonasal +length, 20.1 (19.7-20.4); zygomatic breadth, 10.4 (10.2-10.6); postpalatal +length, 7.3 (7.0-7.7); least interorbital breadth, 4.2 (4.0-4.4); length +of incisive foramina, 4.8 (4.4-5.6); length of rostrum, 7.2 (6.6-7.5); breadth +of braincase, 9.6 (9.5-9.8); depth of cranium, 7.4 (7.1-7.6); alveolar length of +maxillary tooth-row, 3.3 (3.1-3.4); for photographs of skull, see <a href="#plate1">Plate 1<i>d</i></a>, and +<a href="#plate3">Plate 3<i>d</i></a>.</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. m. nigrescens</i> and <i>B. m. brunneus</i>, +see accounts of those subspecies. From <i>B. m. pallidus</i>, <i>B. m. infernatis</i> differs +in: sides, ears, and dorsum paler (less of dark brown); venter whitish gray +rather than gray with tinge of buff and brown; forefeet and hind feet paler; +tail bicolored, not unicolored; incisive foramina longer and not constricted +posteriorly; mastoid process turning dorsally and sickle-shaped at posteriormost +point rather than capitate.</p> +</div> + +<p><i>Remarks.</i>—<i>B. m. infernatis</i> resembles <i>B. m. handleyi</i> more than +any other subspecies in color of pelage and in external and cranial +dimensions. The resemblance in color between <i>B. m. pallidus</i>, in +certain parts of its range, and <i>B. m. handleyi</i> may have resulted +from nearly parallel selective forces that gave rise to two subspecies, +widely separated geographically. The same relation obtains between +<i>B. m. infernatis</i> and <i>B. m. handleyi</i>. Both inhabit arid river +basins. In them, pale soil and low relative humidity are important +passive factors of selection that give adaptive value to the pale +colors of pelage of both <i>infernatis</i> and <i>handleyi</i>.</p> + +<p>Specimens from 6<sup>1</sup>/<sub>2</sub> mi. SW Izucár de Matemores, and 1 mi. SSW +Tilapa, Puebla, are intergrades between <i>B. m. infernatis</i> and <i>B. m. +<span class="pagenum"><a name="Page_620" id="Page_620">[Pg 620]</a></span> +pallidus</i>. These specimens are intermediate in color and cranial +characters between the aforementioned subspecies but possess more +of the pale brown overtones seen in paratypes of <i>pallidus</i>, and are +best referred to that subspecies.</p> + +<div class="smaller"> +<p><i>Specimens examined</i> (All in Univ. Michigan, Mus. Zool.).—Total 18, all +from the Republic of México and distributed as follows: <span class="smcap">Puebla</span>, Tepanaco, +6000 ft., 3, Tehuacán, 5400 ft., 3. <span class="smcap">Oaxaca</span>: Type locality, 3100 ft., 12 +(including the type).</p> + +<p><i>Marginal records.</i>—See specimens examined.</p> +</div> + + +<div class="caption3"><a name="Baiomys_musculus_musculus" id="Baiomys_musculus_musculus"></a> +<b>Baiomys musculus musculus</b> (Merriam)</div> + +<div class="species_ref"><i>Sitomys musculus</i> Merriam, Proc. Biol. Soc. Washington, 7:170, September +29, 1892; Lyon and Osgood, Bull. U. S. Nat. Mus., 62:135, January 15, +1909.</div> + +<div class="species_ref"><i>Baiomys musculus</i> [= <i>musculus</i>], Mearns, Bull. U. S. Nat. Mus., 56:381, +April 13, 1907; Hooper, Jour. Mamm., 36:29, May 26, 1955.</div> + +<div class="species_ref"><i>Peromyscus musculus</i> [<i>musculus</i>], J. A. Allen and Chapman, Bull. Amer. +Mus. Nat. Hist., 9:203, June 16, 1897; Elliot, Field Columb. Mus. Publ., +105(4):135, July 1, 1905; Osgood, N. Amer. Fauna, 28:257, April 17, +1909 (part).</div> + +<div class="species_ref">[<i>Peromyscus</i>] <i>musculus</i>, Trouessart, Cat. Mamm., 1:518, 1898.</div> + +<div class="species_ref">[<i>Peromyscus</i>] <i>musculus</i> [<i>musculus</i>], Elliot, Field Columb. Mus. Publ., +95(4):175, July 15, 1904.</div> + +<div class="species_ref"><i>Baiomys musculus musculus</i>, Miller, Bull. U. S. Nat. Mus., 79:137, December +31, 1912 (part); Miller, Bull. U. S. Nat. Mus., 128:318, April +29, 1924 (part); Ellerman, The Families and Genera of Living Rodents, +2:402, March 21, 1941; Poole and Schantz, Bull. U. S. Nat. Mus., 178:258, +March 6, 1942; Davis, Jour. Mamm., 25:394, December 12, 1944 +(part); Hooper, Jour. Mamm., 28:50, February 15, 1947 (part); +Hall and Villa-R., Univ. Kansas Publs., Mus. Nat. Hist., 1:460, December +27, 1949 (part); Hall and Villa-R., Anal. del Inst. Biol., +21:196, September 28, 1950 (part); Goldman, Smith. Miscl. Coll., 115:336, +July 31, 1951 (part); Miller and Kellogg, Bull. U. S. Nat. Mus., +205:512, March 3, 1955 (part); Hooper, Occas. Papers Mus. Zool. Univ. +Michigan, 565:13, March 31, 1955; Hall and Kelson, The Mammals of +North America, 2:661, March 31, 1959 (part).</div> + +<div class="species_ref"><i>B.</i> [<i>aiomys</i>] <i>m.</i> [<i>usculus</i>] <i>musculus</i>, Hooper, Jour. Mamm., 33:97, February +18, 1952 (part); Packard, Univ. Kansas Publs., Mus. Nat. Hist., 9:400; +December 19, 1958.</div> + +<div class="species_ref"><i>Baiomys taylori allex</i>, Hall and Kelson, The Mammals of North America, +2:659, March 31, 1959 (part).</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult female, skin and skull; No. 33437/45460 U. S. Nat. Mus. (Biol. Surv. +Coll.); Colima (City), Colima, Republic of México, obtained on March 9, +1892, by E. W. Nelson, original number 2055.</p> + +<p><i>Range.</i>—Southwestern Nayarit and northwestern Jalisco, south into Colima, +thence eastward into Michoacán. Zonal range: part of arid Lower Tropical +Subzone of Goldman (1951:330); approximates part of the Nayarit-Guerrero +Biotic Province of Goldman and Moore (1945:349). Occurs from near sea +level in Colima up to 5800 feet in Jalisco.</p> + +<p><i>Diagnosis.</i>—Size large for the species; dorsum Olive-Brown in darkest +series to Buffy Brown with tones of Fawn Color in the palest series; guard +<span class="pagenum2"><a name="Page_621" id="Page_621">[Pg 621]</a></span> +hairs of dorsum black-tipped, gray basally (in some specimens, guard hairs +gray-tipped with subterminal black band, and gray base); underfur of dorsum +black-tipped with subterminal band of fawn to buff, Neutral Gray basally; face +and head paler than back because of greater number of fawn-colored and buff-colored +hairs; hairs on throat and chin white to base; venter and flanks Pale +Olive-Buff in palest series to Gray (Pale Gull Gray) in darkest series; individual +hairs of venter tipped with white to buff, basally Gray (Dark Gull +Gray); forefeet and hind feet white to gray with flesh-colored undertones; tail +faintly bicolored, individual hairs above black, below white; nasals flared anteriorly; +zygoma and zygomatic plate thick. Average and extreme external +and cranial measurements for 8 adults from Armeria, Colima, are as follows: +total length, 125.5 (115-135); length of tail vertebrae, 47.5 (42-54); length of +body, 75.6 (68-81); length of hind foot, 16.5 (16-17); occipitonasal length, +20.3 (19.8-20.7); zygomatic breadth, 10.7 (10.3-11.1); postpalatal length, 7.4 +(7.1-7.7); least interorbital breadth, 4.0 (3.9-4.1); length of incisive foramina, +4.3 (4.1-4.5); length of rostrum, 7.3 (6.9-7.6); breadth of braincase, 9.8 +(9.4-10.0); depth of cranium, 7.1 (6.7-7.2); alveolar length of maxillary +tooth-row, 3.4 (3.3-3.6); for photographs of skull, see +<a href="#plate1">Plate 1<i>e</i></a>, and <a href="#plate3">Plate 3<i>e</i></a>.</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. m. brunneus</i>, <i>B. m. infernatis</i>, and +<i>B. m. pallidus</i>, see accounts of those subspecies. From <i>B. m. nigrescens</i>, <i>B. m. +musculus</i> differs in: dorsum paler throughout (less of blackish brown); region +of face and ears paler, more buff and fawn-colored hairs rather than blackish-brown +to grayish hairs; vibrissae paler; venter paler, less dark gray and less of +sooty-colored undertones, tips of hairs whitish to pale Olive-Buff rather than +light gray at tips becoming darker basally; forefeet and hind feet paler, whitish +to pale buff-color with flesh-colored undertones, not sooty-colored to dark +brown; tail paler below; nasals flaring outward, not tapering toward midline +at anteriormost point; zygoma more massive; larger in external and cranial +dimensions.</p> +</div> + +<p><i>Remarks.</i>—Merriam (1892:170) described <i>Sitomys</i> [= <i>Baiomys</i>] +<i>musculus</i> on the basis of 23 specimens (from Colima City, Colima; +Armeria, Colima; Plantinar, and Zapotlán, Jalisco). According to +the original description, <i>B. musculus</i> resembled a small house mouse +and was smaller than any known species of <i>Sitomys</i> except <i>S. taylori</i> +[= <i>Baiomys taylori</i>]. From <i>taylori</i>, <i>musculus</i> differed in being +larger [in size of body], and in having longer ears and tail, and +larger hind feet. When Allen and Chapman (1897:203) described +<i>Peromyscus</i> [= <i>Baiomys</i>] <i>musculus brunneus</i> from Jalapa, Veracruz, +the specimens described by Merriam from Colima and Jalisco became +representative of the nominal subspecies <i>B. m. musculus</i>. +Osgood (1909:258) assigned specimens from Colima, Guerrero, +Jalisco, Michoacán, Morelos, Oaxaca, Puebla, Sinaloa, Veracruz, +and Zacatecas to the subspecies <i>musculus</i>. Subsequently, Russell +(1952:21) named the subspecies <i>pallidus</i> from the arid lowlands +of Morelos; Hooper (1952:96) described the subspecies <i>infernatis</i> +<span class="pagenum"><a name="Page_622" id="Page_622">[Pg 622]</a></span> +from northern Oaxaca and southeastern Puebla; and Goodwin +(1959:1) described a new subspecies <i>nebulosus</i> from the Oaxaca +highlands. Each of the subspecies mentioned immediately above +was described from within the geographic range assigned to <i>B. m. +musculus</i> by Osgood (<i>loc. cit.</i>). Hall and Kelson (1959:661) +mapped the range of <i>B. m. musculus</i> so as to include Colima, parts +of Jalisco, Michoacán, Guerrero, Oaxaca, and Veracruz. Lukens +(1955:159), in a study of the mammals of Guerrero, has shown that +the characters attributed to <i>B. m. pallidus</i> are not significantly +different from those of pygmy mice studied from Guerrero. He +(<i>loc. cit.</i>) concluded that: (1) if the specimens of pygmy mice +from central Guerrero were typical of the subspecies <i>musculus</i>, +then <i>pallidus</i> did not deserve subspecific recognition, or; (2) the +name <i>B. m. musculus</i> should be restricted to the larger pygmy mice +inhabiting the lowlands immediately adjacent to the Pacific Coast +and the area to the north. My data (see <a href="#fig12">Figure 12</a>) show pygmy +mice from southwestern Nayarit, northwestern and central Jalisco, +Colima, and parts of Michoacán to be significantly larger in certain +cranial and external measurements than pygmy mice from Guerrero, +Oaxaca, Morelos, and parts of Puebla. This finding essentially +corroborates Hooper's (1952a:96) findings. It seems advisable, +therefore, to restrict the range of <i>B. musculus musculus</i> to the large +mice inhabiting west-central México and the coastal lowlands of +Colima and Michoacán. The name <i>pallidus</i> is applicable to the +smaller mice occupying Morelos, southwestern Puebla, Guerrero, +Oaxaca, and southwestern Chiapas.</p> + +<p><i>B. m. musculus</i> intergrades with <i>B. m. pallidus</i> in eastern +Michoacán and central and western Guerrero. Specimens from +San José Prura and 12 mi. S Tzitzio, Michoacán, though referable +to <i>B. m. musculus</i> because of slightly larger size of crania are +intermediate in size and color between the smaller and slightly +darker <i>pallidus</i> to the south and east and the larger, slightly paler +<i>musculus</i> to the northwest.</p> + +<div class="smaller"> +<a name="FNanchor_1_10" id="FNanchor_1_10"></a> +<a name="FNanchor_2_11" id="FNanchor_2_11"></a> +<a name="FNanchor_3_12" id="FNanchor_3_12"></a> +<a name="FNanchor_4_13" id="FNanchor_4_13"></a> +<p><i>Specimens examined.</i>—Total 156 all from the Republic of México, and +distributed as follows: <span class="smcap">Nayarit</span>: 3 mi. NNW Las Varas, 150 ft., 1. +<span class="smcap">Jalisco</span>: 7 mi. W Ameca, 4000 ft., +2<a href="#Footnote_1_10" class="fnanchor">[10]</a>; +<i>6 mi. W Ameca</i>, 4300 ft., 3<a href="#Footnote_1_10" class="fnanchor">[10]</a>; +<i>10 mi. S Ameca</i>, 5800 ft., 1<a href="#Footnote_1_10" class="fnanchor">[10]</a>; +<i>13 mi. S, 15 mi. W Guadalajara</i>, 3; <i>13 mi. S, 9<sup>1</sup>/<sub>2</sub> mi. W Guadalajara</i>, 1; +<i>3 mi. ENE Santa Cruz de las Flores</i>, 1; 27 mi. S, 12 mi. W Guadalajara, 1; +<i>4 mi. NE Autlán</i>, 3000 ft., 5<a href="#Footnote_1_10" class="fnanchor">[10]</a>; +<i>Sierra de Autlán</i>, 5000 ft., 2<a href="#Footnote_1_10" class="fnanchor">[10]</a>; +<i>2<sup>1</sup>/<sub>2</sub> mi. NNE Autlán</i>, 3000 ft., 8; 2 mi. SSE Autlán, 1; +<i>5 mi. S Purificación</i>, 2; Chamela Bay, 1<a href="#Footnote_1_10" class="fnanchor">[10]</a>; +<i>2 mi. N La Resolana</i>, 1500 ft., 6<a href="#Footnote_1_10" class="fnanchor">[10]</a>; +<i>1 mi. N San Gabriel</i>, 4000 ft., 32<a href="#Footnote_1_10" class="fnanchor">[10]</a>; +2 mi. N Cuidad Guzmán, 5000 ft., 1; 3 mi. E Navidad, 4300 ft., 10<a href="#Footnote_1_10" class="fnanchor">[10]</a>. +<span class="smcap">Colima</span>: <i>type locality</i>, 10<a href="#Footnote_2_11" class="fnanchor">[11]</a> +(including the type); <i>3 mi. SE Colima</i> (<i>City</i>), 5<a href="#Footnote_1_10" class="fnanchor">[10]</a>; +<i>4 mi. SW Colima City</i>, 1; Armeria, 200 ft., 8<a href="#Footnote_2_11" class="fnanchor">[11]</a>; +<i>Paso del Río</i>, 20<a href="#Footnote_1_10" class="fnanchor">[10]</a>. +<span class="pagenum2"><a name="Page_623" id="Page_623">[Pg 623]</a></span> +<span class="smcap">Michoacán</span>: 12 mi. S Tzitzio, 6<a href="#Footnote_1_10" class="fnanchor">[10]</a>; +San José Prura, 4<a href="#Footnote_3_12" class="fnanchor">[12]</a>; +1 mi. E, 6 mi. S Tacámbaro, 4000 ft., 3<a href="#Footnote_4_13" class="fnanchor">[13]</a>; +La Salada, 3<a href="#Footnote_2_11" class="fnanchor">[11]</a>; +<sup>1</sup>/<sub>2</sub> mi. SE Coalcomán, 15<a href="#Footnote_1_10" class="fnanchor">[10]</a>.</p> + +<p><i>Marginal records.</i>—<span class="smcap">Nayarit</span>: 3 mi. NNW Las Varas, 150 ft. +<span class="smcap">Jalisco</span>: 3 mi. E Navidad, 4300 ft.; 27 mi. S, 12 mi. W Guadalajara. +<span class="smcap">Michoacán</span>: 12 mi. S Tzitzio; San José Prura; <sup>1</sup>/<sub>2</sub> mi. SE Coalcomán. +<span class="smcap">Colima</span>: Armeria, 200 ft. <span class="smcap">Jalisco</span>: Chamela Bay.</p> +</div> + +<div class="footnote"><p><a name="Footnote_1_10" id="Footnote_1_10"></a> +<a href="#FNanchor_1_10"><span class="label">[10]</span></a> Univ. Michigan, Museum of Zoology.</p></div> + +<div class="footnote"><p><a name="Footnote_2_11" id="Footnote_2_11"></a> +<a href="#FNanchor_2_11"><span class="label">[11]</span></a> U. S. Nat. Museum (Biol. Surv. Coll.).</p></div> + +<div class="footnote"><p><a name="Footnote_3_12" id="Footnote_3_12"></a> +<a href="#FNanchor_3_12"><span class="label">[12]</span></a> Chicago Natural History Museum.</p></div> + +<div class="footnote"><p><a name="Footnote_4_13" id="Footnote_4_13"></a> +<a href="#FNanchor_4_13"><span class="label">[13]</span></a> Univ. California, Mus. Vert. Zoology.</p></div> + + +<div class="caption3"><a name="Baiomys_musculus_nigrescens" id="Baiomys_musculus_nigrescens"></a> +<b>Baiomys musculus nigrescens</b> (Osgood)</div> + +<div class="species_ref"><i>Peromyscus musculus nigrescens</i> Osgood, Proc. Biol. Soc. Washington, +17:76, March 21, 1904; Elliot, Field Columb. Mus. Publ., 105(4):136, +July 1, 1905; Lyon and Osgood, Bull. U. S. Nat. Mus., 62:135, January +15, 1909; Osgood, N. Amer. Fauna, 28:259, April 17, 1909.</div> + +<div class="species_ref"><i>Baiomys musculus nigrescens</i>, Miller, Bull. U. S. Nat. Mus., 79:137, March +31, 1912; Miller, Bull. U. S. Nat. Mus., 128:318, April 29, 1924; Goodwin, +Bull. Amer. Mus. Nat. Hist., 68(1):40, December 12, 1934; Ellerman, +The Families and Genera of Living Rodents, 2:402, March 21, +1941; Poole and Schantz, Bull. U. S. Nat. Mus., 178:259, March 6, 1942; +Hooper, Jour. Mamm., 28:50, February 15, 1947; Goldman, Smith. Miscl. +Coll., 115:357, July 31, 1951; Miller and Kellogg, Bull. U. S. Nat. Mus., +205:513, March 3, 1955; Booth, Walla Walla Publs., Dept. Biol. Sci., +20:15, July 10, 1957; Hall and Kelson, The Mammals of North America, +2:661, March 31, 1959 (part).</div> + +<div class="species_ref">[<i>Peromyscus musculus</i>] <i>nigrescens</i>, Elliot, Field Columb. Mus. Publ., +95(4):176, 1904.</div> + +<div class="species_ref"><i>B.</i> [<i>aiomys</i>] <i>m.</i> [<i>usculus</i>] <i>nigrescens</i>, Goodwin, Bull. Amer. Mus. Nat. Hist., +79(2):160, May 29, 1942; Hooper, Jour. Mamm., 33:97, February 18, +1952 (part); Packard, Univ. Kansas Publs., Mus. Nat. Hist., 9:399, +December 19, 1958.</div> + +<div class="species_ref"><i>B.</i> [<i>aiomys</i>] <i>m.</i> [<i>usculus</i>] <i>musculus</i>, Booth, Walla Walla Publs., Dept. Biol. +Sci., 20:15, July 10, 1957 (part).</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult female, skin and skull; No. 76827 U. S. Nat. Mus. (Biol. +Surv. Coll.); Valley of Comitán, Chiapas, Republic of México, obtained on +December 9, 1895, by E. W. Nelson and E. A. Goldman, original number 8719.</p> + +<p><i>Range.</i>—Southern coastal region and eastern parts of Chiapas, southeastward +into central and southern Guatemala, thence south into El Salvador (see +<a href="#fig10">Figure 10</a>). Zonal range: parts of Lower Austral; also occurs in parts of the +arid division of the Upper Tropical Life-zone, and in parts of the arid division +of the Lower Tropical Life-zone; approximates a part of the Chiapas Highlands +Biotic Province of Goldman and Moore (1945:349), and parts of the +Guatemalan Subregion of Smith (1949:235).</p> + +<p><i>Diagnosis.</i>—Size medium to small for the species; dorsum Vandyke Brown +mixed with blackish, individual hairs black-tipped with a subterminal band of +Warm Buff, Neutral Gray at base; guard hairs of dorsum black distally, Neutral +Gray basally; hairs on sides grayish-brown, facial region like dorsum; chin +buffy-brown; vibrissae brown, ventrally some white; venter creamy-buff to +grayish, individual hairs creamy-buff at tips, gray basally; in region of throat +and chin, hairs tipped with Ochraceous-Buff; dorsal surface of forefeet and +hind feet dull whitish gray to brownish-black; tail indistinctly bicolored, dusky +above, grayish to brownish below; incisive foramina short, wide medially; +<span class="pagenum2"><a name="Page_624" id="Page_624">[Pg 624]</a></span> +average and extreme external and cranial measurements of 15 adults from 6 +mi. NW Tonalá, Chiapas, are as follows: total length, 107.5 (100-116); +length of tail vertebrae, 41.1 (33-48); length of body, 66.1 (62-73); length +of hind foot, 15.0 (14-16); length of ear, 10.9 (10-12); occipitonasal length, +18.9 (18.4-19.7); zygomatic breadth, 9.8 (9.4-10.2); postpalatal length, 6.9 +(6.6-7.4); least interorbital breadth, 3.7 (3.5-3.8); length of incisive foramina, +4.4 (4.1-4.8); length of rostrum, 6.7 (6.1-7.1); breadth of braincase, 9.2 +(9.0-9.4); depth of cranium, 6.9 (6.5-7.3); alveolar length of maxillary tooth-row, +3.1 (2.9-3.2); for photographs of skull, see <a href="#plate1">Plate 1<i>f</i></a>, +and <a href="#plate3">Plate 3<i>f</i></a>.</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. m. handleyi</i>, <i>B. m. grisescens</i>, <i>B. m. +musculus</i>, <i>B. m. pallidus</i>, and <i>B. m. pullus</i>, see accounts of those subspecies.</p> + +<p>From <i>B. m. brunneus</i>, <i>B. m. nigrescens</i> differs in: dorsum blackish-brown +rather than reddish to ochraceous brown; face and ears brownish-black rather +than brownish with tinges of ochraceous; vibrissae darker; forefeet and hind +feet darker; venter with more grayish tones; dorsalmost part of zygomatic plate +projects farther anteriorly; interparietal oval to diamond-shaped and narrower +anteroposteriorly; zygomata narrower at anteriormost part; slightly smaller in +most cranial and external measurements.</p> + +<p>From <i>B. m. infernatis</i>, <i>B. m. nigrescens</i> differs in: dorsum darker; region of +face and ears darker; venter buffy to gray rather than whitish-buff; vibrissae +darker; forefeet and hind feet darker; tail darker above and below; incisive +foramina shorter, more constricted laterally; cranium slightly smaller in most +dimensions.</p> +</div> + +<p><i>Remarks.</i>—Hooper (1952a:93-94) reported specimens from the +coastal strip of southern Chiapas as the most intensely pigmented, +whereas, specimens from central and western Chiapas were +distinctly paler. Crania of specimens from the coastal region of +southern Chiapas were smaller than crania from the central highlands +and mountains of Chiapas. My studies essentially corroborate +the findings of Hooper. The gradation of color between the pale +brown <i>pallidus</i> to the north in Oaxaca, and the brownish-black +<i>nigrescens</i> to the south in Chiapas is extremely gradual. Specimens +from the central and western parts of Chiapas (see <a href="#fig10">Figure 10</a> for +localities) are difficult to assign to either <i>pallidus</i> or <i>nigrescens</i>. +Equal justification exists for assignment to either subspecies. I +have assigned the specimens to <i>nigrescens</i> because they are geographically +closer to the type locality of <i>nigrescens</i>. Specimens +from Reforma, Oaxaca (assigned by Hooper, 1952a:93-94, to +<i>nigrescens</i>), are nearly identical in size and color to paratypes of +<i>pallidus</i>. I assign the Reforma specimens to <i>pallidus</i>.</p> + +<p>The darkest of all the specimens examined and assigned to +<i>nigrescens</i> are from 1 mi. NW San Salvador and 1 mi. S Los Planes, +El Salvador. The variations in color in this subspecies closely +correspond to degree of relative humidity; the palest samples are +from areas of low relative humidity and the darkest are from areas +<span class="pagenum"><a name="Page_625" id="Page_625">[Pg 625]</a></span> +of high relative humidity. In view of the present state of differentiation +of specimens from the southern coastal areas of Chiapas and +mountainous areas of El Salvador, it would seem that populations +there might be incipient subspecies.</p> + +<div class="smaller"> +<a name="FNanchor_1_14" id="FNanchor_1_14"></a> +<a name="FNanchor_2_15" id="FNanchor_2_15"></a> +<a name="FNanchor_3_16" id="FNanchor_3_16"></a> +<a name="FNanchor_4_17" id="FNanchor_4_17"></a> +<p><i>Specimens examined.</i>—Total 319. <span class="smcap">Chiapas</span>: +<i>17 mi. W Bochil</i>, 1<a href="#Footnote_1_14" class="fnanchor">[14]</a>; +<i>15 mi. W Bochil</i>, 1<a href="#Footnote_1_14" class="fnanchor">[14]</a>; +<i>14 mi. W Bochil</i>, 1<a href="#Footnote_1_14" class="fnanchor">[14]</a>; +Bochil, 6<a href="#Footnote_2_15" class="fnanchor">[15]</a>; +Ocuilapa, 3500 ft., 5<a href="#Footnote_3_16" class="fnanchor">[16]</a>; +<i>5 mi. NNW Tuxtla Gutiérrez</i>, 9; <i>11 km. W Tuxtla Gutiérrez</i>, 800 m., +2<a href="#Footnote_2_15" class="fnanchor">[15]</a>; +<i>10 km. W Tuxtla Gutiérrez</i>, 800 m., 2<a href="#Footnote_2_15" class="fnanchor">[15]</a>; +<i>Tuxtla Gutiérrez</i>, 2600 ft., 8<a href="#Footnote_3_16" class="fnanchor">[16]</a>, 11; +<i>Ocozocoautla</i>, 10<a href="#Footnote_2_15" class="fnanchor">[15]</a>, 2<a href="#Footnote_3_16" class="fnanchor">[16]</a>; +25 mi. E Comitán, Las Margaritas, 1250 m., 5<a href="#Footnote_4_17" class="fnanchor">[17]</a>, +24<a href="#Footnote_2_15" class="fnanchor">[15]</a>; Cintalpa, 555 m., 1<a href="#Footnote_1_14" class="fnanchor">[14]</a>, +18<a href="#Footnote_2_15" class="fnanchor">[15]</a>, 3<a href="#Footnote_4_17" class="fnanchor">[17]</a>; +<i>Jiquilpilas</i>, 2000 ft., 1<a href="#Footnote_3_16" class="fnanchor">[16]</a>; +San Bartolome, 3<a href="#Footnote_3_16" class="fnanchor">[16]</a>; +<i>type locality</i>, 5700 ft., 26<a href="#Footnote_3_16" class="fnanchor">[16]</a> (including the type); +15 mi. SW Las Cruces, 1; Villa Flores, 600 m., 12<a href="#Footnote_2_15" class="fnanchor">[15]</a>; +<i>23 mi. S Comitán</i>, 1<a href="#Footnote_1_14" class="fnanchor">[14]</a>; <i>15 mi. S, 2 mi. E La Trinitaria</i>, 4; +<i>30 mi. S Comitán</i>, 2<a href="#Footnote_1_14" class="fnanchor">[14]</a>; +35 mi. S Comitán, 1<a href="#Footnote_1_14" class="fnanchor">[14]</a>; +<i>3 mi. E Arriga</i>, 1<a href="#Footnote_1_14" class="fnanchor">[14]</a>; +6 mi. NW Tonalá, 19; <i>Tonalá</i>, 8<a href="#Footnote_3_16" class="fnanchor">[16]</a>; +<i>Los Amates</i>, 1<a href="#Footnote_1_14" class="fnanchor">[14]</a>; +Pijijiapan, 10 m., 7<a href="#Footnote_2_15" class="fnanchor">[15]</a>; +Mapastepec, 45 m., 25<a href="#Footnote_2_15" class="fnanchor">[15]</a>, +4<a href="#Footnote_4_17" class="fnanchor">[17]</a>.</p> + +<p><span class="smcap">Guatemala</span>: Chanquejelve, 1<a href="#Footnote_1_14" class="fnanchor">[14]</a>; +<i>Nentón</i>, 3000 ft., 1<a href="#Footnote_3_16" class="fnanchor">[16]</a>; +Jacaltenango, 5400 ft., 8<a href="#Footnote_3_16" class="fnanchor">[16]</a>; +La Primavera, 5<a href="#Footnote_1_14" class="fnanchor">[14]</a>; 4 mi. S Guatemala City, 4700 ft., 3; +<i>5 mi. S Guatemala City</i>, 4050 ft., 10; <i>6 mi. S Guatemala City</i>, 4680 ft., 1; +<i>Lake Amatitlán</i>, 4500 ft., 13<a href="#Footnote_3_16" class="fnanchor">[16]</a>; +El Progresso (Distrito Santa Rosa), 3<a href="#Footnote_2_15" class="fnanchor">[15]</a>; +<i>2 mi. N, 1 mi. W Cuilapa</i>, 2980 ft., 1<a href="#Footnote_1_14" class="fnanchor">[14]</a>; +<i>1 mi. WSW El Molino</i> (<i>Distrito Santa Rosa</i>), 2; +<i>2<sup>1</sup>/<sub>2</sub> mi. W, 2<sup>1</sup>/<sub>4</sub> mi. N San Cristobal</i>, 2900 ft., 1; +El Zapote, 1<a href="#Footnote_2_15" class="fnanchor">[15]</a>.</p> + +<p><span class="smcap">El Salvador</span>: 1 mi. NW San Salvador, 29; 1 mi. S Los Planes, 15.</p> + +<p><i>Marginal Records.</i>—<span class="smcap">Chiapas</span>: Bochil; 25 mi. E Comitán, Las Margaritas, +1250 ft. <span class="smcap">Guatemala</span>: Chanquejelve; La Primavera; Jacaltenango, 5400 ft.; +4 mi. S Guatemala City, 4700 ft.; El Progresso. <i>El Salvador</i>: 1 mi. NW San Salvador; +1 mi. S Los Planes. <span class="smcap">Guatemala</span>: El Zapote. <span class="smcap">Chiapas</span>: Mapastepec, +45 m.; Pijijiapan, 10 m.; 6 mi. NW Tonalá; 15 mi. SW Las Cruces; Cintalpa, 555 m.; Ocuilapa, 3500 ft.</p> +</div> + +<div class="footnote"><p><a name="Footnote_1_14" id="Footnote_1_14"></a> +<a href="#FNanchor_1_14"><span class="label">[14]</span></a> American Museum of Natural History.</p></div> + +<div class="footnote"><p><a name="Footnote_2_15" id="Footnote_2_15"></a> +<a href="#FNanchor_2_15"><span class="label">[15]</span></a> Univ. Michigan, Museum of Zoology.</p></div> + +<div class="footnote"><p><a name="Footnote_3_16" id="Footnote_3_16"></a> +<a href="#FNanchor_3_16"><span class="label">[16]</span></a> U. S. Nat. Museum (Biol. Surv. Coll.).</p></div> + +<div class="footnote"><p><a name="Footnote_4_17" id="Footnote_4_17"></a> +<a href="#FNanchor_4_17"><span class="label">[17]</span></a> University of Florida Collections.</p></div> + + +<div class="caption3"><a name="Baiomys_musculus_pallidus" id="Baiomys_musculus_pallidus"></a> +<b>Baiomys musculus pallidus</b> Russell</div> + +<div class="species_ref"><i>Baiomys musculus pallidus</i> Russell, Proc. Biol. Soc. Washington, January 29, +1952; Davis and Russell, Jour. Mamm., 35:75, February 10, 1954; Miller +and Kellogg, Bull. U. S. Nat. Mus., 205:512; Hall and Kelson, The Mammals +of North America, 2:662, March 31, 1959.</div> + +<div class="species_ref"><i>Peromyscus musculus brunneus</i>, Elliot, Field Columb. Mus. Publ., 115(8):203, +1907 (part).</div> + +<div class="species_ref"><i>Peromyscus musculus</i> [<i>musculus</i>], Osgood, N. Amer. Fauna, 28:257, April +17, 1909 (part).</div> + +<div class="species_ref"><i>Baiomys musculus musculus</i>, Miller, Bull. U. S. Nat. Mus., 79:137, December +31, 1912 (part); Miller, Bull. U. S. Nat. Mus., 128:318, April 29, 1924 +(part); Davis, Jour. Mamm., 25:394, December 12, 1944 (part); Hooper, +Jour. Mamm., 28:50, February 15, 1947 (part); Goldman, Smith, Miscl. +Coll., 115:336, July 31, 1951 (part); Miller and Kellogg, Bull. U. S. +Nat. Mus., 205:512, March 3, 1955 (part); Booth, Walla Walla Publs., +Dept. Biol. Sci., 20:15, July 10, 1957 (part); Hall and Kelson, The +Mammals of North America, 2:661, March 31, 1959 (part); Goodwin, +Amer. Mus. Novitates, 1929:1, March 5, 1959.</div> + +<div class="species_ref"><i>B.</i> [<i>aiomys</i>] <i>m.</i> [<i>usculus</i>] <i>musculus</i>, Hooper, Jour. Mamm., 33:97, February +18, 1952 (part).</div> + +<div class="species_ref"><i>B.</i> [<i>aiomys</i>] <i>m.</i> [<i>usculus</i>] <i>nigrescens</i>, Hooper, Jour. Mamm., 33:97, February +18, 1952 (part).</div> + +<div class="species_ref"><i>Baiomys musculus nebulosus Goodwin</i>, Amer. Mus. Novitates, 1929, March +5, 1959.</div> + +<p><span class="pagenum"><a name="Page_626" id="Page_626">[Pg 626]</a></span></p> + +<div class="smaller"> +<p><i>Type.</i>—Adult female, skin and skull; No. 4501 Texas A&M Cooperative +Wildlife Collection; 12 kms. NW Axochiapán, 3500 feet, Morelos, Republic +of México, obtained on July 28, 1950, by W. B. Davis, original number 5112.</p> + +<p><i>Range.</i>—Guerrero thence eastward into Morelos and west central Puebla +along the southern edge of the Transverse Volcanic Biotic Province (Goldman +and Moore, 1945:349), south into Oaxaca, see <a href="#fig10">Figure 10</a>. Zonal range: largely +Arid Lower Tropical Subzone of Goldman (1951:330). Occurs from near sea +level in Oaxaca and Guerrero up to 6550 feet in Oaxaca.</p> + +<p><i>Diagnosis.</i>—Size medium for the species; dorsum Buffy Brown in palest +series to Olive-Brown in darkest series, individual hairs Warm Buff, Neutral +Gray basally, some with black tips and a subterminal band of Warm Buff, guard +hairs of dorsum black-tipped, gray basally; hairs on sides creamy-buff, gray +basally; face same color as back fading to white on throat; vibrissae white-tipped, +pale brown basally; venter, whitish with tinges of buff on lower throat, +individual hairs having tips white to buffy-white, light gray basally; dorsal +surface of forefeet and hind feet whitish to flesh-color; tail indistinctly bicolored, +brownish above, grayish brown below; zygoma bowed as in <i>B. m. +grisescens</i>; tail short; average and extreme external and cranial measurements +for 17 adults from Tehuantepec, Oaxaca, are: total length, 117.3 (110-126); +length of tail vertebrae, 46.9 (41-51); length of body, 70.4 (65-76); +length of hind foot, 15.8 (15-16); occipitonasal length, 18.9 (18.2-20.1); zygomatic +breadth, 10.1 (9.7-10.6); postpalatal length, 6.9 (6.6-7.5); least interorbital +breadth, 3.8 (3.6-3.9); length of incisive foramina, 4.4 (4.2-4.7); +length of rostrum, 6.7 (6.3-7.2); breadth of braincase, 9.3 (8.7-9.7); depth of +cranium, 6.6 (6.4-6.8); alveolar length of maxillary tooth-row, 3.2 (3.1-3.4); +for photographs of skull, see <a href="#plate1">Plate 1<i>g</i></a>, and <a href="#plate3">Plate 3<i>g</i></a>.</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. m. brunneus</i> and <i>B. m. infernatis</i>, +see accounts of those subspecies.</p> + +<p>From <i>B. m. musculus</i>, <i>B. m. pallidus</i> differs in: dorsum more olive-gray and +brown, less ochraceous on either side of mid-dorsal region; face below eye +grayish, not buffy; sides gray with buffy overtone, not creamy with light yellow +overtones; venter grayish-white rather than an olive-buff; zygomata more +tapering anteriorly; maxillary part of zygoma narrower when viewed from +above; external and cranial dimensions smaller.</p> + +<p>From <i>B. m. nigrescens</i>, <i>B. m. pallidus</i> differs in: dorsum paler, fewer black +hairs medially; face paler, less sooty; vibrissae brownish with white tips rather +than black with brownish tips; venter paler; dorsal surface of forefeet and +hind feet whitish to flesh-colored rather than sooty to dusky-white; tail paler; +nasals slightly more attenuated; averaging slightly larger in external and cranial +measurements.</p> +</div> + +<p><i>Remarks.</i>—Russell (1952:21) described <i>pallidus</i>, on the basis of +specimens from the arid Balsas Basin, of Morelos, as pale gray +dorsally. After examining the original material from Morelos, I +find the dorsal color of <i>pallidus</i> to be much closer to a buffy brown +than a pale grayish. Even so, smaller size differentiates <i>pallidus</i> +from <i>musculus</i>. <i>B. m. infernatis</i>, not <i>B. m. pallidus</i>, is the most +pallid of all named subspecies of <i>B. musculus</i>.</p> + +<p><span class="pagenum"><a name="Page_627" id="Page_627">[Pg 627]</a></span></p> + +<p><i>B. m. pallidus</i> intergrades to the northwest with <i>B. m. musculus</i>, +to the northeast with <i>B. m. infernatis</i>, and to the southeast with +<i>B. m. nigrescens</i>.</p> + +<p>According to Goodwin (1959:2), <i>B. m. nebulosus</i> (named on the +basis of one specimen) differs from <i>B. m. musculus</i> [= <i>pallidus</i>] +from southern Oaxaca in: darker and longer pelage; larger skull; +interorbital region broader and less constricted posteriorly. From +<i>B. m. nigrescens</i> and <i>B. m. brunneus</i>, <i>B. m. nebulosus</i> differs as +follows: pelage longer and softer; skull larger.</p> + +<p>Study of specimens of <i>B. musculus</i> from Oaxaca reveals considerable +variation in external and cranial measurements as well as +color, corresponding to that reported by Goodwin (<i>loc. cit.</i>). +Specimens from higher altitudes average somewhat darker and +larger in external and cranial size than those at lower elevations. +These differences seem to be microgeographic and not of subspecific +rank. Among specimens that I have studied in Oaxaca are +several from different localities (KU 63052, an adult male, from 3 +mi. W Miahuatlán; KU 68964, an adult male from 3 mi. W Mitla, +6000 ft.; KU 63055, an adult female from 3 mi. S Candelario, 1200 +ft.) that, according to Goodwin (<i>in. litt.</i>) match <i>nebulosus</i> in reported +color, size of body and skull (except for the region of the +rostrum).</p> + +<p>Two of the three specimens (KU 63052 and 63055) are the +darkest of a series in which the palest are inseparable from <i>B. m. +pallidus</i>. Goodwin, who kindly compared the three specimens +with the type of <i>nebulosus</i>, mentioned (<i>in. litt.</i>) that the skull of +the type has a slenderer rostrum. Included in the series of skulls +of <i>B. m. pallidus</i> from 3 mi. W Mitla are several adults (not seen +by Goodwin) with slender rostra. <i>B. m. nebulosus</i> is judged to +be a synonym of <i>B. m. pallidus</i>.</p> + +<p>Populations of pygmy mice occurring in partially isolated areas +of highland in Oaxaca seem to me to be incipient subspecies.</p> + +<div class="smaller"> +<a name="FNanchor_1_18" id="FNanchor_1_18"></a> +<a name="FNanchor_2_19" id="FNanchor_2_19"></a> +<a name="FNanchor_3_20" id="FNanchor_3_20"></a> +<a name="FNanchor_4_21" id="FNanchor_4_21"></a> +<a name="FNanchor_5_22" id="FNanchor_5_22"></a> +<a name="FNanchor_6_23" id="FNanchor_6_23"></a> +<a name="FNanchor_7_24" id="FNanchor_7_24"></a> +<p><i>Specimens examined.</i>—Total 824 all from the Republic of México and distributed +as follows: <span class="smcap">Puebla</span>: 2 mi. S Atlixco, 5800 ft., 1; +<i>1 mi. SSW Tilapa</i>, 5800 ft., 2; <i>6 mi. SW Izucár de Matemores</i>, 7; +<i>Piaxtla</i>, 3900 ft., 4<a href="#Footnote_1_18" class="fnanchor">[18]</a>; +Acatlán, 4100 ft., 1. <span class="smcap">Morelos</span>: 5 mi. W Tepoztlán, 6000 ft., +7<a href="#Footnote_2_19" class="fnanchor">[19]</a>; <i>1 mi. W Tepoztlán</i>, +6000 ft., 9<a href="#Footnote_2_19" class="fnanchor">[19]</a>; <i>2 mi. SW Tepoztlán</i>, +7000 ft., 1<a href="#Footnote_3_20" class="fnanchor">[20]</a>; <i>Cuernvaca</i>, +9<a href="#Footnote_2_19" class="fnanchor">[19]</a>; +<i>6 mi. W Yautepec</i>, 4500 ft., 1<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +<i>Yautepec</i>, 12<a href="#Footnote_2_19" class="fnanchor">[19]</a>; +<i>3 mi. N Alpuyeca</i>, 4000 ft., 2<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +<i>Puente de Ixtla</i>, 2<a href="#Footnote_2_19" class="fnanchor">[19]</a>; +<i>Tetecala</i>, 4<a href="#Footnote_4_21" class="fnanchor">[21]</a>; +<i>2 km. S Jonacatepec</i>, 4500 ft., 6<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +<i>type locality</i>, 6 (including the type). +<span class="smcap">Guerrero</span>: <i>Yerbabuena</i>, 1800 m., 1; +<i>Cueva de tia Juana</i> [= <i>1.5 km. SSW Yerbabuena</i>], 1; +<i>Laguna Honda</i>, 1840 m. [= <i>1.5 km. S Yerbabuena</i>], 3; +9 mi. SE Taxco, 3800 ft., 1<a href="#Footnote_5_22" class="fnanchor">[22]</a>; +<i>17 km. S Taxco</i>, 4000 ft., 2<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +<i>Iguala</i>, 5<a href="#Footnote_2_19" class="fnanchor">[19]</a>; +<i>3.2 km. SSE Iguala</i>, 970 m., 1; 1 km. SSE Texcaizintla, 1600 m., 2; +<i>Teloloapán</i>, 20<a href="#Footnote_2_19" class="fnanchor">[19]</a>, +5<a href="#Footnote_7_24" class="fnanchor">[24]</a>; <i>1 km. N Chapa</i>, 1470 m., 6; +<i>Chapa</i>, 1470 m., 5; El Limón, 3<a href="#Footnote_1_18" class="fnanchor">[18]</a>; +2<sup>1</sup>/<sub>2</sub> mi. W Mexcala, 2100 ft., 1<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +<i>Río Balsas</i>, 1<a href="#Footnote_1_18" class="fnanchor">[18]</a>; +Ayusinaha [= Ayotzinapa], 1<a href="#Footnote_1_18" class="fnanchor">[18]</a>; +<i>Tlapa</i>, <span class="pagenum2"><a name="Page_628" id="Page_628">[Pg 628]</a></span> +3900 ft, 1<a href="#Footnote_1_18" class="fnanchor">[18]</a>; +<i>2.5 mi. S Almolonga</i>, 5600 ft., 13<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +<i>1 km. N Zihuatanejo</i>, 1; Zihuatanejo Bay, 4<a href="#Footnote_2_19" class="fnanchor">[19]</a>; +<i>Las Gatas</i> [= <i>2 km. S. Zihuatanejo</i>], 2; +<i>2 km. SSE Zihuatanejo</i>, 9; <i>4 mi. W Chilpancingo</i>, 5800 ft., +3<a href="#Footnote_3_20" class="fnanchor">[20]</a>; <i>Chilpancingo</i>, 4800 ft., +14<a href="#Footnote_1_18" class="fnanchor">[18]</a>, 21<a href="#Footnote_2_19" class="fnanchor">[19]</a>, +45<a href="#Footnote_4_21" class="fnanchor">[21]</a>; <i>2 mi. N Tixtla</i>, 4400 ft., +3<a href="#Footnote_3_20" class="fnanchor">[20]</a>; <i>3.2 km. S Chilpancingo</i>, 4; +<i>Cd. Chamilpa</i> [= <i>12 km. ESE Chilpancingo</i>], 5; +<i>Tlalixtaquilla</i>, 4200 ft., 2<a href="#Footnote_1_18" class="fnanchor">[18]</a>; +<i>15 km. S. Chilpancingo</i>, 4300 ft., 10<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +<i>1 mi. SW Colotlipa</i>, 2700 ft., 16<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +<i>2 mi. SW Colotlipa</i>, 2700 ft., 1<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +<i>Achuitzotla</i>, 2800 ft., 7<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +<i>8 mi. SW Colotlipa</i>, 1<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +<i>5 mi. S Rincón</i>, 2600 ft., 2<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +<i>8 mi. SW Tierra Colorado</i>, 600 ft., 1<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +Río Aguacatillo, <i>30 km. N Acapulco</i>, 1000 ft., 3<a href="#Footnote_3_20" class="fnanchor">[20]</a>; +5 mi. ESE Tecpán, 50 ft., 9; <i>Ejido Viejo</i>, <i>12 km. NNW Acapulco</i>, 1; +<i>2 mi. NNW Acapulco</i>, 7; Acapulco, 3<a href="#Footnote_1_18" class="fnanchor">[18]</a>, +3<a href="#Footnote_4_21" class="fnanchor">[21]</a>; +Omentepec, 200 ft., 7<a href="#Footnote_1_18" class="fnanchor">[18]</a>. +<span class="smcap">Oaxaca</span>: <i>4 mi. E Huajuapám</i>, 5000 ft., 1; 2 mi. +NW Tamazulapán, 6550 ft., 1; Yalalag, 3000 ft., 5<a href="#Footnote_1_18" class="fnanchor">[18]</a>; +<i>11 mi. NW Oaxaca</i> [<i>City</i>], 1; <i>Yaganiza</i>, 3900 ft., +1<a href="#Footnote_1_18" class="fnanchor">[18]</a>; Oaxaca [City], 5000 ft., +15, 7<a href="#Footnote_4_21" class="fnanchor">[21]</a>, 7<a href="#Footnote_2_19" class="fnanchor">[19]</a>, +5<a href="#Footnote_7_24" class="fnanchor">[24]</a>; <i>3 mi. ESE Oaxaca</i> [<i>City</i>], 30; +<i>4 mi. ESE Oaxaca</i> [<i>City</i>], 5050 ft., 1; <i>10 mi. SE Oaxaca</i> [City], +1<a href="#Footnote_5_22" class="fnanchor">[22]</a>; <i>Cerro Ocotepec</i>, +1<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +Tepantepec, 9<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>1 mi. E Tlacolula</i>, 5500 ft., 53<a href="#Footnote_2_19" class="fnanchor">[19]</a>; +<i>3 mi. W Mitla</i>, 11; Jalapa, El Campanario, 1<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>2 mi. SE Matalán</i>, 5950 ft., 14; <i>Lachiguiri</i>, 2<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>Tres Cruces</i>, 10<a href="#Footnote_6_23" class="fnanchor">[23]</a>; <i>Agua Blanca</i>, +11<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>San José</i>, 1<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +Reforma, 30<a href="#Footnote_2_19" class="fnanchor">[19]</a>, +7<a href="#Footnote_4_21" class="fnanchor">[21]</a>, 10<a href="#Footnote_6_23" class="fnanchor">[23]</a>, +6<a href="#Footnote_7_24" class="fnanchor">[24]</a> <i>Totolapa</i>, +1<a href="#Footnote_1_18" class="fnanchor">[18]</a>; +<i>Nejapa</i>, <i>85 km. WNW Tehuantepec</i>, 500 m., 12<a href="#Footnote_2_19" class="fnanchor">[19]</a>, +6<a href="#Footnote_7_24" class="fnanchor">[24]</a>; <i>Chicapa</i>, +2<a href="#Footnote_1_18" class="fnanchor">[18]</a>; <i>Gueladu</i> +[= <i>Jalapa</i>], 6<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>Juchitán</i>, <i>Laguna Superior</i>; Manteca, 8<a href="#Footnote_6_23" class="fnanchor">[23]</a>, +1<a href="#Footnote_6_23" class="fnanchor">[23]</a>; San Bartolo, 3000 ft., +1<a href="#Footnote_1_18" class="fnanchor">[18]</a>; <i>Ejutla</i>, 1400 m., +21<a href="#Footnote_2_19" class="fnanchor">[19]</a>; <i>El Bambita</i>, <i>Tequisitlán</i> 4<a href="#Footnote_6_23" class="fnanchor">[23]</a>; <i>Mixtequilla</i>, +2<a href="#Footnote_6_23" class="fnanchor">[23]</a>; <i>Guiencola</i>, +5<a href="#Footnote_6_23" class="fnanchor">[23]</a>; <i>Tehuantepec</i>, 200 ft., +26<a href="#Footnote_1_18" class="fnanchor">[18]</a>, 11<a href="#Footnote_2_19" class="fnanchor">[19]</a>; +<i>Sola de la Vega</i>, 26<a href="#Footnote_2_19" class="fnanchor">[19]</a>, +3<a href="#Footnote_7_24" class="fnanchor">[24]</a>; +Huilotepec, 13<a href="#Footnote_1_18" class="fnanchor">[18]</a>, +3<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>Santa Lucia</i>, 24<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>Cerro de Paste</i>, <i>Tenango</i>, 7<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>Sta. C. Quieri</i>, 3<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>Santa Marie Ecatepec</i>, <i>Zarzamora</i>, +13<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>Rincón Bamba</i>, 11<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>3 mi. W Miahuatlán</i>, 5300 ft., 1; <i>Miahuatlán</i>, +12<a href="#Footnote_2_19" class="fnanchor">[19]</a>, 1<a href="#Footnote_6_23" class="fnanchor">[23]</a>, +6<a href="#Footnote_7_24" class="fnanchor">[24]</a>; +<i>San Juan Acaltepec</i>, 5<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>Zapotitlán</i>, 1<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +<i>Llano Grande</i>, 3<a href="#Footnote_1_18" class="fnanchor">[18]</a>; +Pinotepa, 700 ft., 2<a href="#Footnote_1_18" class="fnanchor">[18]</a>; +Juquila, 8<a href="#Footnote_1_18" class="fnanchor">[18]</a>; +<i>Arroyo</i>, <i>San Juan</i>, <i>north of Cerro Otate</i>, +1<a href="#Footnote_6_23" class="fnanchor">[23]</a>; +Cerro Otate, 3<a href="#Footnote_6_23" class="fnanchor">[23]</a>; 3 mi. S Candelaria, 1.</p> + +<p><i>Marginal records.</i>—<span class="smcap">Morelos</span>: 5 mi, W Tepoztlán, +6000 ft. <span class="smcap">Puebla</span>: 2 mi. S Atlixco, 5800 ft.; +Acatlán, 4100 ft. <span class="smcap">Oaxaca</span>: 2 mi. NW Tamazulapán, +6550 ft; Tepantepec; Oaxaca [City], 5000 ft; Yalalag, 3000 ft; Jalapa, El +Campanario; Reforma; Huilotepec; 3 mi. S Candelaria; Cerro Otate; Pinotepa, +700 ft. <span class="smcap">Guerrero</span>: Acapulco; Zihuatanejo Bay; El Limón; +9 mi. SE Taxco, 3800 ft.</p> +</div> + +<div class="footnote"><p><a name="Footnote_1_18" id="Footnote_1_18"></a> +<a href="#FNanchor_1_18"><span class="label">[18]</span></a> U. S. Nat. Museum (Biol. Surv. Coll.).</p></div> + +<div class="footnote"><p><a name="Footnote_2_19" id="Footnote_2_19"></a> +<a href="#FNanchor_2_19"><span class="label">[19]</span></a> Univ. Michigan, Museum of Zoology.</p></div> + +<div class="footnote"><p><a name="Footnote_3_20" id="Footnote_3_20"></a> +<a href="#FNanchor_3_20"><span class="label">[20]</span></a> Texas A & M, Cooperative Wildlife Research Collection.</p></div> + +<div class="footnote"><p><a name="Footnote_4_21" id="Footnote_4_21"></a> +<a href="#FNanchor_4_21"><span class="label">[21]</span></a> Chicago Natural History Museum.</p></div> + +<div class="footnote"><p><a name="Footnote_5_22" id="Footnote_5_22"></a> +<a href="#FNanchor_5_22"><span class="label">[22]</span></a> California Academy of Sciences.</p></div> + +<div class="footnote"><p><a name="Footnote_6_23" id="Footnote_6_23"></a> +<a href="#FNanchor_6_23"><span class="label">[23]</span></a> American Museum of Natural History.</p></div> + +<div class="footnote"><p><a name="Footnote_7_24" id="Footnote_7_24"></a> +<a href="#FNanchor_7_24"><span class="label">[24]</span></a> University of Florida Collections.</p></div> + + +<div class="caption3"><a name="Baiomys_musculus_pullus" id="Baiomys_musculus_pullus"></a> +<b>Baiomys musculus pullus</b> Packard</div> + +<div class="species_ref"><i>Baiomys musculus pullus</i> Packard, Univ. Kansas Publs., Mus. Nat. Hist., +9:401, December 19, 1958.</div> + +<div class="species_ref"><i>Baiomys musculus grisescens</i>, Goodwin, Bull. Amer. Mus. Nat. Hist., 79(2):161, +May 29, 1942 (part); Miller and Kellogg, Bull. U. S. Nat. Mus., +205:513, March 3, 1955 (part); Hall and Kelson, The Mammals of +North America, 2:661, March 31, 1959 (part).</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult female, skin and skull; No. 71605 University of Kansas Museum +of Natural History; 8 mi. S Condega, Estelí, Nicaragua, obtained on July +15, 1956, by A. A. Alcorn, original number 4218.</p> + +<p><i>Range.</i>—West-central Nicaragua, from Matagalpa northwest into the valley +of the Río Estelí, east as far as Jinotega, see <a href="#fig10">Figure 10</a>. Zonal range: Upper +Tropical Life-zone.</p> + +<p><i>Diagnosis.</i>—Size medium to small for the species; dorsum Fuscous-Black, individual +hairs black-tipped with a subterminal band of Ochraceous-Buff, Neutral +Gray at base; some hairs on dorsum all black to Neutral Gray at base; hair on +sides Neutral Gray tinged with blackish; face blackish, becoming buffy on sides +<span class="pagenum2"><a name="Page_629" id="Page_629">[Pg 629]</a></span> +of head, and white on throat; vibrissae black; tail unicolored Chaetura Black; +forefeet and hind feet sooty to dusky-white; mid-ventral region of venter white, +hairs white to base; in region of anus and throat, hairs white-tipped, Neutral +Gray at base; average and extreme external and cranial measurements of the +type and 16 paratypes are as follows: total length, 117.3 (111-121); length of +tail vertebrae, 47.2 (44-50); length of body, 70.4 (66-74); length of hind +foot, 15.5 (14-17); length of ear from notch, 11.9 (10-13); occipitonasal +length, 19.3 (18.9-19.8); zygomatic breadth, 10.2 (9.7-10.6); postpalatal length, +7.0 (6.8-7.3); least interorbital breadth, 3.9 (3.8-4.1); length of incisive foramina, +4.3 (4.0-4.6); length of rostrum, 7.0 (6.5-7.4); breadth of braincase, 9.6 +(9.3-10.0); depth of cranium, 7.0 (6.8-7.3); alveolar length of maxillary tooth-row, +3.1 (3.0-3.2); for photographs of skull, see <a href="#plate1">Plate 1<i>h</i></a>, +and <a href="#plate3">Plate 3<i>h</i></a>.</p> + +<p><i>Comparisons.</i>—From <i>B. m. grisescens</i>, <i>B. m. pullus</i> differs in: dorsum and +tail darker; sides and lateral parts of venter grayish instead of buffy-brown, thus +forming distinct mid-ventral white stripe; average length of body and tail +significantly longer, thus total length greater; maxillary tooth-row significantly +shorter; slightly larger in other cranial and external dimensions.</p> + +<p>From <i>B. m. nigrescens</i>, <i>B. m. pullus</i> differs in: dorsum slightly darker; face +grayish, not sooty; mid-ventral white stripe (absent in most specimens of +<i>nigrescens</i>) present and becoming grayish laterally; tail darker, less hairy, and +averaging significantly longer; smaller in most external and cranial dimensions.</p> +</div> + +<p><i>Remarks.</i>—<i>B. m. pullus</i> resembles <i>B. m. nigrescens</i> in size and +color but can readily be distinguished from <i>nigrescens</i> by the shorter +tail. <i>B. m. pullus</i> intergrades with <i>nigrescens</i> as shown by specimens, +referable to <i>B. m. nigrescens</i>, from 1 mi. NW San Salvador +and from 1 mi. S Los Planes, El Salvador. In color of the dorsum, +specimens from these localities are intermediate between <i>nigrescens</i> +and <i>pullus</i>.</p> + +<p>The mid-ventral white stripe characteristic of <i>pullus</i> is present in +three of 28 adults from El Salvador. Goodwin (1942:160) reported +white hairs on the pectoral region of several topotypes of <i>B. m. +grisescens</i>. The areas of white hairs on the venter of <i>grisescens</i> occur +in approximately 10 per cent of the specimens examined, whereas +in <i>pullus</i>, the frequency of occurrence is 90 per cent. The areas of +white hairs in <i>grisescens</i> are in broad patches on the pectoral region, +while in <i>pullus</i>, a white stripe passes from the pectoral region to the +inguinal region in both males and females. I know of no selective +advantage that the presence of this white stripe would confer on the +mice.</p> + +<div class="smaller"> +<p><i>Specimens examined.</i>—Total 46, all from <span class="smcap">Nicaragua</span>, and distributed as +follows: Type locality, 32 (including the type); <i>9 mi. NNW Estelí</i>, 8; <i>8 mi. +NNW Estelí</i>, 3; San Rafael Del Norte, 1 (Amer. Mus. Nat. Hist.); <i>1 mi. NW +Jinotega</i>, 1; Matagalpa, 1 (Amer. Mus. Nat. Hist.).</p> + +<p><i>Marginal records.</i>—<span class="smcap">Nicaragua</span>: San Rafael Del Norte; Matagalpa; type +locality.</p> +</div> + +<p><span class="pagenum"><a name="Page_630" id="Page_630">[Pg 630]</a></span></p> + + +<div class="caption3"><a name="Baiomys_taylori" id="Baiomys_taylori"></a> +<b>Baiomys taylori</b><br /> +<br /> +Northern Pygmy Mouse<br /> +<br /> +(Synonymy under subspecies)</div> + +<div class="smaller"> +<p><i>Type.</i>—<i>Hesperomys</i> (<i>Vesperimus</i>) <i>taylori</i> Thomas, Ann. Mag. Nat. Hist., +Ser. 5, 19:66, January, 1887.</p> + +<p><i>Range.</i>—Southeastern Arizona and southwestern New Mexico, south into +Chihuahua and Durango, just east of the Sierra Madre Occidental, thence +southeast through Zacatecas, Aquascalientes, Jalisco, Querétaro, and Guanajuato; +two fingerlike projections extend northward, one on the west along the coast of +Sinaloa into southern Sonora, and the other on the east covering eastern San +Luis Potosí, Tamaulipas, eastern Coahuila, Nuevo León, into south, southeast, +and north-central Texas. Southern margin of range in central México approximates +the 19th degree of latitude (see <a href="#fig11">Figure 11</a>). Arid lower and arid +upper subdivisions of the Tropical Life-zone in south; principally Lower +Sonoran and Lower Austral life-zones in north.</p> + +<p><i>Characters for ready recognition.</i>—Unless otherwise noted, characters are +usable for the age-categories of adult and old adult. Differs from <i>B. musculus</i> +in: hind foot less than 16 millimeters; occipitonasal length less than 19 millimeters; +zygomatic breadth less than 10 millimeters; rostrum deflected ventrally +at frontoparietal suture rather than curving gradually toward anteriormost point +of nasals; cingular ridges and secondary cusps on teeth reduced or absent; +basihyal having entoglossal process much reduced or absent, shoulders of +basihyal not protruding anteriorly, but more flattened (characteristic of all age +categories); baculum having narrower shaft, knob-shaped tip, wings at base +projecting laterally, baculum less than 3 millimeters long; short process of +incus attenuate; muscular process of posterior crus of stapes reduced.</p> + +<p><i>Characters of the species.</i>—Size small (extremes in external measurements of +adults: total length, 87-123; length of tail vertebrae, 34-53; length of hind +foot, 12-15; length of ear, 9-12). Upper parts pale drab or reddish-brown to +almost black; underparts grayish to cream-buff.</p> +</div> + +<p><i>Geographic variation.</i>—Eight subspecies are here recognized (see +<a href="#fig11">Figure 11</a>). Features that vary geographically are mostly the same +as those that do so in <i>B. musculus</i> (see <a href="#Page_609">page 609</a>).</p> + +<p>External and cranial size is less in <i>B. t. allex</i>, the southernmost +subspecies, and progressively more in <i>B. t. paulus</i>, <i>B. t. taylori</i>, +<i>B. t. ater</i>, <i>B. t. subater</i>, <i>B. t. fuliginatus</i>, <i>B. t. canutus</i>, and <i>B. t. +analogous</i>. Size is largest in subspecies that occur at higher altitudes. +Those subspecies are <i>B. t. analogous</i> and <i>B. t. fuliginatus</i>. +The correlation with Bergman's Rule is less exact in <i>B. taylori</i> than +in <i>B. musculus</i>. It is noteworthy that the smallest subspecies, <i>B. t. +allex</i>, occurs in the area where the two species are sympatric.</p> + +<p>There is close correlation in <i>B. taylori</i>, as also in <i>B. musculus</i>, of +darker pelages with zones of high relative humidity. The subspecies +having dark pelages are: <i>analogous</i>, <i>fuliginatus</i>, and <i>subater</i>. +The two first-mentioned subspecies occur at high altitudes, and +<span class="pagenum"><a name="Page_631" id="Page_631">[Pg 631]</a></span> +the other, <i>subater</i>, occurs in the humid coastal region of Texas. +The paler subspecies, <i>taylori</i>, <i>canutus</i>, and <i>allex</i>, occur at lower altitudes. +Two subspecies that occur at relatively high altitudes, <i>ater</i> +and <i>paulus</i>, are reddish-brown. The color of pelage in these subspecies +resembles the color of soil upon which they live. Blair and +Blossom (1948:5) demonstrated close correlation of color of soil +with color of pelage in <i>B. t. ater</i> by use of an Ives tint photometer.</p> + +<div class="fig_center"> +<a name="fig11" id="fig11"></a> +<img src="images/fig_11.png" width="531" height="597" alt="" /> +<div class="fig_caption"><span class="smcap">Fig. 11.</span> Distribution of <i>Baiomys taylori</i>. Known localities of occurrence are +represented by circles and black dots; the former denote localities that are +peripheral (marginal) for the subspecies concerned.<br /> +<br /> +<table style="text-align:left" summary="species"> +<tr> + <td> + 1. <i>B. t. allex</i><br /> + 2. <i>B. t. analogous</i><br /> + 3. <i>B. t. ater</i><br /> + 4. <i>B. t. canutus</i><br /> + </td> + <td> + + </td> + <td> + 5. <i>B. t. fuliginatus</i><br /> + 6. <i>B. t. paulus</i><br /> + 7. <i>B. t. subater</i><br /> + 8. <i>B. t. taylori</i><br /> + </td> +</tr> +</table> +</div> +</div> + +<p><span class="pagenum"><a name="Page_632" id="Page_632">[Pg 632]</a></span></p> + +<div class="caption3"><i>Natural History</i></div> + +<p><i>Habitat and numbers.</i>—The habitat occupied by the northern +pygmy mouse ranges from sparse grassy areas along rock walls in +central México (see Davis, 1944:394), and mesquite-cactus associations +in southern Texas (Blair, 1952:242) to heavy stands of +grasses such as <i>Bouteloua</i> sp., <i>Andropogon</i> sp., <i>Hilaria</i> sp., and +sacaton grass intermixed with <i>Yucca glauca</i> in New Mexico, Arizona +(see Hoffmeister 1956:281), and Chihuahua. Baker (1951:213) +reports the species from 2 km. W El Carrizo, Tamaulipas, in dense +grass and weeds at the edge of a cornfield. Hooper (1953:7) recorded +the northern pygmy mouse in a cultivated field overgrown +with herbaceous vegetation at Pano Ayuctle, Tamaulipas. In the +State of Sinaloa, Hooper (1955b:13) obtained specimens in grass +and among shrubs and vines bordering a fallow field. The northern +pygmy mouse, in general, lives in situations more xerophytic and +more grassy than does the southern pygmy mouse.</p> + +<p>The northern pygmy mouse, as the southern pygmy mouse, is +locally abundant in its geographic range. Stickel and Stickel (<i>op. +cit.</i>: 145) pointed out that on the third night of live-trapping in +Bexar County, Texas, there was a sudden increase in unmarked +pygmy mice trapped. This increase in numbers, after the resident +population was seemingly marked, followed a one-half inch rainfall. +Collectors from the University of Kansas, myself included, have had +similar experiences in trapping these mice. In the Mexican states +of Guanajuato, Querétaro, and Jalisco, <i>B. taylori</i> is one of the commonest +small mammals. In New Mexico and Arizona and the Mexican +states of Sonora and Sinaloa, nevertheless, these mice are rare.</p> + +<p>Stickel and Stickel (<i>loc. cit.</i>) thought that the home range normal +for <i>B. taylori</i> in a grassy habitat was less than 100 square feet, but +Blair (1953:10) thought that a complete home range had not been +recorded by Stickel and Stickel.</p> + +<p><i>Behavior.</i>—The northern pygmy mouse is crepuscular to nocturnal +and where I trapped in northern Mexico was one of the first +small rodents to appear in my traps in the evening. Hall and +Villa-R (1949:460) recorded this habit in Michoacán. Observations +of wild-taken <i>B. taylori</i> held in captivity, lend support to its being +crepuscular. Captives were rarely active in bright lights, but in +diffuse or dim lights the same mice were active.</p> + +<p>Blair (1941:381) pointed out that captive <i>B. t. subater</i> were much +more tolerant of one another than mice of the genus <i>Peromyscus</i>. +He pointed out also that males aided in care of young. In one +<span class="pagenum"><a name="Page_633" id="Page_633">[Pg 633]</a></span> +litter born in captivity in the course of my study, the female killed +the male when the young were four days old. In another instance, +the female and two eight-day-old young were killed by the male. +Until that time, the male, female, and young had lived together +peacefully. In other litters born in captivity, adult males did not +harm the other mice.</p> + +<p>I have noted, as Blair (<i>loc. cit.</i>) did, that <i>B. taylori</i> utters high-pitched +squeals in a "singing" posture resembling that of the coyote, +yet remains silent when being handled.</p> + +<p>The northern pygmy mouse makes runways in the grass, in miniature +resembling those of <i>Microtus</i>, and often uses runways constructed +by <i>Sigmodon</i>. A small firm nest of finely shredded plant +material (mostly grasses) is constructed in burrows or under logs, +rocks, or fallen cactus plants. Thomas (1888:447) recorded nests of +fine curly grass and cornsilk. Secondary refuge nests are not uncommon. +Thomas (<i>loc. cit.</i>) states, "If other mice live in the same +place, the individuals of <i>Baiomys</i> watch till others disappear, then +suddenly steal part of the other nest and run to their own with it."</p> + +<p><i>Enemies and food.</i>—Little is recorded of the animals that prey +upon the northern pygmy mouse. Twente and Baker (1951:120) +found remains of <i>B. taylori</i> in 16 per cent of barn owl pellets (<i>Tyto +alba pratincola</i>) collected 21 mi. SW Guadalajara, Jalisco. Presumably +most of the crepuscular and early nocturnal raptorial birds +and carnivorous mammals feed on these mice.</p> + +<p>Food of <i>B. taylori</i> consists in part of grass seeds and leaves, +prickly pear (<i>Opuntia</i> sp.) and the softer exposed parts of roots +of vegetation among which the mice reside.</p> + +<p><i>Reproduction.</i>—The northern pygmy mouse breeds throughout +the year. The only months in which I have not recorded pregnant +females or females with young are June and October. Forty-one +records of embryos or young per litter average 2.48 (less than in +<i>B. musculus</i>), and range from as few as one to as many as four +per litter.</p> + + +<div class="caption3"><a name="Baiomys_taylori_allex" id="Baiomys_taylori_allex"></a> +<b>Baiomys taylori allex</b> (Osgood)</div> + +<div class="species_ref"><i>Peromyscus allex</i> Osgood, Proc. Biol. Soc. Washington, 17:76-77, March +21, 1904; Elliot, Field Columb. Mus. Publ., 105(6):135, July 1, 1905; +Lyon and Osgood, Bull. U. S. Nat. Mus., 62:124, January 15, 1909.</div> + +<div class="species_ref"><i>Baiomys taylori allex</i>, Packard, Proc. Biol. Soc. Washington, 71:17, April +11, 1958; Hall and Kelson, The Mammals of North America, 2:659, +March 31, 1959 (part).</div> + +<div class="species_ref">[<i>Peromyscus</i>] <i>allex</i>, Elliot, Field Columb. Mus. Publ., 95(4):175, July 15, +1904.</div> + +<div class="species_ref"><i>Peromyscus taylori paulus</i>, Osgood, N. Amer. Fauna, 28:255, April 17, +1909 (part).</div> + +<p><span class="pagenum"><a name="Page_634" id="Page_634">[Pg 634]</a></span></p> + +<div class="species_ref"><i>Baiomys taylori paulus</i>, Miller, Bull. U. S. Nat. Mus., 79:137, December +31, 1912 (part); Miller, Bull. U. S. Nat. Mus., 128:317, April 29, 1924 +(part); Ellerman, The Families and Genera of Living Rodents, British +Mus. Nat. Hist., 2:402, March 21, 1941 (part); Poole and Schantz, +Bull. U. S. Nat. Mus., 178:259, March 6, 1942; Goldman, Smith. Miscl. +Coll., 115:373, July 31, 1951 (part); Miller and Kellogg, Bull. U. S. +Nat. Mus., 205:512, March 3, 1955 (part); Hall and Kelson, The Mammals +of North America, 2:659, March 31, 1959 (part).</div> + +<div class="species_ref"><i>Baiomys taylori analogous</i>, Hall and Kelson, Univ. Kansas Publs., Mus. +Nat. Hist., 5:367, December 15, 1952 (part).</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult male, skin and skull; No. 33429/45452 U. S. Nat. Mus. +(Biol. Surv. Coll.); Colima (City), Colima, Republic of México, obtained on +March 7, 1892, by E. W. Nelson, original number 2029.</p> + +<p><i>Range.</i>—Colima, western lowlands of Michoacán and Jalisco, thence north +into southern half of Nayarit, see <a href="#fig11">Figure 11</a>. Zonal range: arid lower tropical, +approximates northern half of the Nayarit-Guerrero Biotic Province of Goldman +and Moore (1945:349). Occurs from near sea level in Nayarit, up to +4000 feet in Jalisco.</p> + +<p><i>Diagnosis.</i>—Size small for the species; dorsal ground color pale grayish-brown, +near Isabella color; mid-dorsal region washed with blackish, individual +guard hairs black to base, other hairs black-tipped with subterminal light +olive bands, Neutral Gray at base; laterally, black-tipped hairs less abundant, +hairs grayish-white to base; venter Pale Gull Gray to whitish, distal half of +individual hairs white, proximal half Neutral Gray; hairs in regions of throat +and chin white to base; facial region colored like dorsum, becoming paler +below eye; in region of mouth, hairs white to base; dorsalmost vibrissae black +to base, others white to base; ears flesh-colored, sparsely haired; tail unicolored, +sparsely haired for the species; dark blotches on tail of some series (particularly +the paratypical series); dorsal and ventral parts of forefeet and hind feet +flesh-colored, whitish to gray in some series. Slightly smaller in most cranial +dimensions. Maxillary part of zygoma forming almost a right angle with +rostrum, rather than tapering at less than a right angle to rostrum; supraoccipital +rounded posteriorly rather than indented on each side of foramen magnum; +cranium, relative to length of rostrum, more nearly square; interparietal large +relative to size of cranium. Average and extreme measurements of five adults +from 2 mi. SSE Autlán are as follows: total length, 100.0 (93-107); length +of tail vertebrae, 40.0 (37-44); length of body, 60.0 (56-63); length of hind +foot, 14.0 (14); length of ear from notch, 10.5 (10-11); occipitonasal length, +17.3 (16.8-17.9); zygomatic breadth, 9.1 (8.7-9.4); postpalatal length, 6.3 +(6.0-6.6); least interorbital breadth, 3.4 (3.3-3.5); length of incisive foramina, +3.9 (3.8-4.0); length of rostrum, 5.5 (5.2-5.8); breadth of braincase, 8.6 (8.0-8.9); +depth of cranium, 6.4 (6.0-6.7); alveolar length of maxillary tooth-row, +3.0 (2.8-3.1); for photographs of skull, see <a href="#plate1">Plate 1<i>i</i></a> +and <a href="#plate4">Plate 4<i>a</i></a>.</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. t. canutus</i>, see account of that subspecies. +From <i>B. t. analogous</i>, <i>B. t. allex</i> differs in: external and cranial dimensions +less; dorsal coloration paler; tail and ears paler and less hairy; dorsum +and belly paler; dorsal and ventral parts of forefeet and hind feet paler; median +parts of incisive foramina less constricted on either side of midline and wider +open laterally; interparietal larger in relation to skull; interorbital breadth greater +relative to occipitonasal length.</p> + +<p><span class="pagenum2"><a name="Page_635" id="Page_635">[Pg 635]</a></span></p> + +<p><i>B. t. allex</i> differs from <i>B. t. paulus</i> as follows: dorsum gray with yellowish-brown +wash rather than fawn to buff; tail unicolored in most series, less hairy; +hind feet flesh-colored to light sooty, rather than whitish; rostrum slightly longer +relative to occipitonasal length; incisive foramina differ from those of <i>paulus</i> +in much the same way as from <i>analogous</i>.</p> +</div> + +<p><i>Remarks.</i>—Osgood (1909:255-256) dismissed as taxonomically unimportant +the differences in color of pelage and size of cranium that +he observed between the specimens from Colima (City), Colima, +representative of <i>allex</i> and those representing <i>paulus</i> and chose to +synonomize <i>allex</i> with <i>paulus</i>. The differences that Osgood (<i>loc. +cit.</i>) deemed "… scarcely worthy of recognition …," are, +in fact, not only worthy of recognition, but also important in an +understanding of the evolution of <i>Baiomys taylori</i> (see speciation +<a href="#Page_659">p. 659</a>). Recently, I (1958b:17-18) studied ten specimens from Colima +(City), Colima, and chose to regard <i>Peromyscus [= Baiomys] +allex</i> as a subspecies. I suggested (<i>loc. cit.</i>) that the geographic +range of <i>B. t. allex</i> might encompass the southern part of Nayarit, +and western Jalisco. Subsequent study of specimens from these +areas reveals that the populations there are referable to <i>allex</i>. Most +of the specimens obtained from these areas, however, merit special +comment.</p> + +<p>In color of pelage, those populations from south of the Río Grande +de Santiago and northwest of Guadalajara (4 mi. SE Ahuacatlán; 1 +mi. E Ixtlán; Etzatlán) show evidence of intergradation with <i>paulus</i> +to the east and south (Magdalena, Tequila, and Tala, Jalisco), and +with populations more closely adjacent to the south bank of that +river. Intergradation is indeed complex in this area. Specimens +from some localities seem to be intergrades between <i>allex</i> and +<i>paulus</i>; from other localities, some specimens are referable to <i>allex</i>, +and the others to <i>paulus</i>; from still other localities, all specimens are +referable to <i>allex</i>.</p> + +<p>A series of 39 specimens from 1 mi. SSE Ameca, 4000 ft., Jalisco, +are uniformly grayish-brown. This series averages grayer than paratypes +of <i>allex</i>. There is little, if any, difference between the series +from 1 mi. SSE Ameca and paratypes of <i>allex</i> in external size of +body, hind foot, length of ear, and size and conformation of the +cranium. Populations from Ameca and vicinity might be expected to +average considerably larger inasmuch as they occur at higher altitudes +(see Bergman's Rule, <a href="#Page_609">p. 609</a>) then the material from the lower +coastal plains to the south in Colima and Michoacán, and at lower +elevations in the west in Jalisco and Nayarit. The means of external +<span class="pagenum"><a name="Page_636" id="Page_636">[Pg 636]</a></span> +and cranial measurements are not significantly different between +the specimens from the highlands and those from the lowlands. In +the area of Ameca where the two species <i>B. musculus</i> and <i>B. taylori</i> +occur together, interspecific competition seems to have limited, perhaps +even reduced, size of external and cranial parts of <i>taylori</i> (see +<a href="#Page_660">p. 660</a>).</p> + +<p>In color, specimens from the northern part of the valley of the +Río Tepalcatepec (10 mi. S, 1 mi. W Apatzingán) in Michoacán +resemble paratypes of <i>allex</i>. Intergradation probably occurs to the +north with <i>analogous</i>.</p> + +<p>In the eight specimens from 13 mi. E and 1 mi. N Talpa de +Allendé, the skull, as reflected in occipitonasal length and zygomatic +breadth relative to length of body, is larger than in other specimens +here assigned to <i>allex</i>. The median part of the belly of the eight +specimens is buff-colored rather than whitish-gray as in typical +<i>allex</i>; the mid-dorsal region also averages darker than in any other +specimens referred to <i>allex</i>. Additional specimens are needed from +this and closely adjacent areas, especially to the west on the coastal +plain, in order to determine more accurately the taxonomic status +of the mice there. At present, it seems best to refer them to <i>allex</i>. +Possibly the population represented by the eight specimens is an +incipient subspecies.</p> + +<p>There is no evidence of hybridization or intergradation of populations +of <i>B. t. allex</i> with any population of <i>B. musculus</i> where the +two species occur together.</p> + +<div class="smaller"> +<a name="FNanchor_1_25" id="FNanchor_1_25"></a> +<a name="FNanchor_2_26" id="FNanchor_2_26"></a> +<a name="FNanchor_3_27" id="FNanchor_3_27"></a> +<a name="FNanchor_4_28" id="FNanchor_4_28"></a> +<p><i>Specimens examined.</i>—Total 233, all from the Republic of México, distributed +as follows: <span class="smcap">Nayarit</span>: 3 mi. SE Mirador, 7; +2 <i>mi. S. Compostela</i>, 2900 ft., 5; 4 <i>mi. N Santa Isabel</i>, 3800 ft., +2<a href="#Footnote_1_25" class="fnanchor">[25]</a>; +<i>2 mi. N Santa Isabel</i>, 3800 ft., 22<a href="#Footnote_1_25" class="fnanchor">[25]</a>; +<i>4 mi SE Ahuacatlán</i>, 5200 ft., 2<a href="#Footnote_2_26" class="fnanchor">[26]</a>; +<i>1 mi. E Ixtlán</i>, 4000 ft., 13<a href="#Footnote_1_25" class="fnanchor">[25]</a>; +1 mi. E Ixtlán del Río, 3700 ft., 1; 2 mi. WNW Valle de Banderas, near sea level, 1. +<span class="smcap">Jalisco</span>: Arroyo de Gavalán, 16<a href="#Footnote_4_28" class="fnanchor">[28]</a>; +Etzatlán, 6<a href="#Footnote_3_27" class="fnanchor">[27]</a>; +<i>Mascota</i>, 3900 ft., 6<a href="#Footnote_3_27" class="fnanchor">[27]</a>; +<i>7 mi W Ameca</i>, 15<a href="#Footnote_1_25" class="fnanchor">[25]</a>; +<i>6 mi. W Ameca</i>, 15<a href="#Footnote_1_25" class="fnanchor">[25]</a>; +<i>3 mi. W Ameca</i>, 5<a href="#Footnote_1_25" class="fnanchor">[25]</a>; +Ameca, 4000 ft., 11<a href="#Footnote_3_27" class="fnanchor">[27]</a>; +<i>1 mi. SSE Ameca</i>, 4000 ft., 38; 2 mi. N Resolana, 1500 ft., +28<a href="#Footnote_1_25" class="fnanchor">[25]</a>; 13 mi. E, +1 mi. N Talpa de Allendé, 8; 2 mi. SSE Autlán, 5; +1 mi. N San Gabriel, 4000 ft., 1<a href="#Footnote_1_25" class="fnanchor">[25]</a>; +Las Canoas, l<a href="#Footnote_4_28" class="fnanchor">[28]</a>. +<span class="smcap">Colima</span>: Type locality, +10<a href="#Footnote_3_27" class="fnanchor">[27]</a> (including the type). +<span class="smcap">Michoacán</span>: 9 mi. S Lombardia, 1500 ft., 1; +<i>3 mi. W Apatzingán</i>, 1000 ft, 1; +Apatzingán, 3<a href="#Footnote_1_25" class="fnanchor">[25]</a>; +10 mi. S, 1 mi. W Apatzingán, 800 ft., 10.</p> + +<p><i>Marginal records.</i>—<span class="smcap">Nayarit</span>: 3 mi. SE Mirador; +1 mi. E Ixtlán del Río. <span class="smcap">Jalisco</span>: Etzatlán; Ameca; +2 mi. N Resolana; Las Canoas. <span class="smcap">Michoacán</span>: 9 mi. +S Lombardia; 10 mi. S, 1 mi. W Apatzingán. <span class="smcap">Colima</span>: +type locality. <span class="smcap">Nayarit</span>: Valle de Banderas.</p> +</div> + +<div class="footnote"><p><a name="Footnote_1_25" id="Footnote_1_25"></a> +<a href="#FNanchor_1_25"><span class="label">[25]</span></a> Univ. Michigan, Museum of Zoology.</p></div> + +<div class="footnote"><p><a name="Footnote_2_26" id="Footnote_2_26"></a> +<a href="#FNanchor_2_26"><span class="label">[26]</span></a> California Academy of Sciences.</p></div> + +<div class="footnote"><p><a name="Footnote_3_27" id="Footnote_3_27"></a> +<a href="#FNanchor_3_27"><span class="label">[27]</span></a> U. S. Nat. Museum (Biol. Surv. Coll.).</p></div> + +<div class="footnote"><p><a name="Footnote_4_28" id="Footnote_4_28"></a> +<a href="#FNanchor_4_28"><span class="label">[28]</span></a> American Museum of Natural History.</p> + +<p><span class="pagenum"><a name="Page_637" id="Page_637">[Pg 637]</a></span></p></div> + + +<div class="caption3"><a name="Baiomys_taylori_analogous" id="Baiomys_taylori_analogous"></a> +<b>Baiomys taylori analogous</b> (Osgood)</div> + +<div class="species_ref"><i>Peromyscus taylori analogous</i> Osgood, N. Amer. Fauna, 28:256, April 17, +1909 (part); Elliott, Check-List Mamm., N. Amer. Cont., West Indies +and Neighboring Seas, Suppl., Amer. Mus. Nat. Hist., p. 44, January +8, 1917.</div> + +<div class="species_ref"><i>Baiomys taylori analogous</i>, Miller, Bull. U. S. Nat. Mus., 79:137, December +31, 1912; Miller, Bull. U. S. Nat. Mus., 128:318, April 29, 1924; Ellerman, +The Families and Genera of Living Rodents, British Mus. Nat. +Hist., 2:402, March 21, 1941; Poole and Schantz, Bull. U. S. Nat. Mus., +178:259, March 6, 1942; Davis, Jour. Mamm., 25:394, December 12, +1944; Hooper, Jour. Mamm., 28:50, February 15, 1947; Hall and Villa-R., +Univ. Kansas Publs., Mus. Nat. Hist., 1:460, December 27, 1949; Hall +and Villa-R., Anal. del Inst. Biol., 21:196, September 28, 1950; Goldman, +Smith. Miscl. Coll., 114:373, July 31, 1951 (part); Hall and +Kelson, Univ. Kansas Publs., Mus. Nat. Hist., 5:367, December 15, +1952 (part); Villa-R., Anal. del Inst. Biol., 23:435, May 20, 1953; Miller +and Kellogg, Bull. U. S. Nat. Mus., 205:512, March 3, 1955; Hooper, +Occas. Papers Mus. Zool. Univ. Michigan, 565:13, March 31, 1955; +Packard, Proc. Biol. Soc. Washington, 71:17, April 11, 1958.</div> + +<div class="species_ref"><i>Peromyscus musculus brunneus</i>, Elliot, Field Columb. Mus. Publ., 115(8):203, +1907 (part).</div> + +<div class="species_ref"><i>Peromyscus musculus</i> [<i>musculus</i>], Osgood, N. Amer. Fauna, 28:258, April +17, 1909 (part).</div> + +<div class="species_ref"><i>Baiomys musculus musculus</i>, Hall and Villa-R., Univ. Kansas Publs., Mus. +Nat. Hist., 1:460, December 27, 1949 (part); Hall and Villa-R., Anal. +del Inst. Biol., 21:196, September 28, 1950 (part).</div> + +<div class="species_ref"><i>Baiomys taylori taylori</i>, Dalquest, Louisiana State Univ. Studies (Biol. Sci. +Ser.), 1:155, December 28, 1953 (part); Hall and Kelson, The Mammals +of North America, 2:660, March 31, 1959 (part).</div> + +<div class="species_ref"><i>Baiomys taylori allex</i>, Hall and Kelson, The Mammals of North America, +2:659, March 31, 1959 (part).</div> + +<div class="species_ref"><i>Baiomys musculus musculus</i>, Hall and Kelson, The Mammals of North +America, 2:661, March 31, 1959 (part).</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult male, skin and skull; No. 120261 U. S. Nat. Mus. (Biol. Surv. +Coll.); Zamora, Michoacán, Republic of México, obtained on January 15, 1903, +by E. W. Nelson, and E. A. Goldman, original number 15764.</p> + +<p><i>Range.</i>—Central and eastern Jalisco south into Michoacán, east through +Guanajuato, Querétaro, thence into Estado México, and Distrito Federal, and +west-central Veracruz, see <a href="#fig11">Figure 11</a>. Zonal range: approximately the Transverse +Volcanic Biotic Province of Moore (1945:218) and of Goldman and +Moore (1945:349). Occurs from 5000 feet, 7 mi. S Ocotlán, Jalisco, up to +8000 feet in Ixtapalapa, Distrito Federal.</p> + +<p><i>Diagnosis.</i>—Size large for the species; dorsum dark Sepia to near blackish +medially in freshly taken specimens (Sepia fading to near Fuscous in prepared +specimens); belly slaty-gray, hairs Deep Neutral Gray near tips and Dusky +Neutral Gray at bases; hairs on back black-tipped with subterminal band of +Ochraceous-Tawny (guard hairs blackish to base); hairs of throat and chin +white-tipped, gray at bases; dorsal vibrissae black, ventral and anteriormost +vibrissae white; hairs on face and sides black-tipped, and Ochraceous-Tawny +at base; ears sparsely haired, individual hairs grayish, blackish, and ochraceous; +<span class="pagenum2"><a name="Page_638" id="Page_638">[Pg 638]</a></span> +tail sooty to blackish dorsally, lighter ventrally; forefeet and hind feet sooty +brown on dorsal and ventral surface. Skull relatively broad interorbitally; +zygoma broad and squared; cranium larger in all dimensions than in most +other subspecies. Average and extreme measurements of 10 adults from 1 mi. +S, 11 mi. W Zamora, 5400 ft., Michoacán, are: total length, 109.4 (102-121); +length of body, 64.3 (58-72); length of tail, 44.9 (39-51); length of hind foot, +14.6 (14-15); occipitonasal length, 18.0 (17.5-18.6); zygomatic breadth, 9.4 +(9.1-9.7); postpalatal length, 6.6 (6.2-7.2); least interorbital breadth, 3.5 +(3.3-3.8); length of incisive foramina, 4.0 (3.8-4.2); length of rostrum, 6.2 +(5.8-6.5); breadth of braincase, 8.7 (8.5-8.9); depth of cranium, 6.6 (6.3-6.9); +alveolar length of maxillary tooth-row, 3.1 (3.0-3.3); for photographs of skull, +see <a href="#plate2">Plate 2<i>a</i></a> and <a href="#plate4">Plate 4<i>b</i></a>.</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. t. allex</i>, <i>B. t. canutus</i>, <i>B. t. paulus</i>, +and <i>B. t. fuliginatus</i>, see accounts of those subspecies. From <i>B. t. taylori</i>, <i>B. t. +analogous</i> differs as follows: sides and dorsum darker, differing most in freshly +prepared specimens; dorsal surface of forefeet and hind feet darker; basal part +of hairs on belly darker gray; frontal bones less constricted, causing less taper +anteriorly in interorbital space; interparietal wider transversely; basioccipital +more expanded laterally, narrowing more abruptly at suture between basioccipital +and basisphenoid.</p> +</div> + +<p><i>Remarks.</i>—The pelage of <i>analogous</i> becomes paler with wear as +pointed out by Osgood (1909:257). A paratype, U. S. Nat. Mus. +120260, and several specimens from 1 mi. S, 11 mi. W Zamora, +Michoacán, are grayish rather than brownish-black. All of these are +old adults having the terminal black parts of the hairs on the dorsum +nearly worn away. Excluding such grayish individuals, <i>B. t. analogous</i>, +like <i>B. t. subater</i> and <i>B. t. fuliginatus</i>, is uniformly brownish-black. +Both <i>analogous</i> and <i>fuliginatus</i> occur in relatively high +mountainous country on dark soils or pedregals, and all three of the +aforementioned subspecies occur in zones of high relative humidity.</p> + +<p><i>B. t. analogous</i> intergrades with <i>B. t. paulus</i> (see account of that +subspecies) and <i>B. t. allex</i> south and west of Lago de Chapala in +Jalisco. Additional specimens are needed from Querétaro and San +Luis Potosí in order to ascertain whether or not <i>B. t. analogous</i> +intergrades with <i>B. t. fuliginatus</i> or <i>B. t. taylori</i>. Specimens from +western Jalisco, in the past referred to <i>B. t. analogous</i>, are referable +to <i>B. t. allex</i> (see account of that subspecies). Specimens obtained +west of, and bordering, the Río del Naranjo in Jalisco show a mixture +of characters of both <i>B. t. allex</i> and <i>B. t. analogous</i>. For example, +specimens from 2 mi. N Ciudad Guzmán resemble <i>analogous</i> +on the dorsum, whereas, on the belly, the individual hairs are white-tipped, +pale gray at the base, and in over-all appearance are whitish-gray, +unlike typical <i>analogous</i> (being like <i>allex</i> instead). The dorsal +surface of the forefeet are sooty to light brownish (as in <i>analogous</i>), +<span class="pagenum"><a name="Page_639" id="Page_639">[Pg 639]</a></span> +whereas, the hind feet are flesh-colored (as in <i>allex</i>). Another +series of specimens from 4 mi. W León, Guanajuato, are intergrades +between <i>B. t. analogous</i> and <i>B. t. paulus</i>. These specimens are +grayish to brownish on the dorsum, have sooty forefeet and hind +feet (more nearly as in <i>analogous</i> than in <i>paulus</i>), are grayish-white +on the venter, and have a distinctly bicolored tail (resembling that +of <i>paulus</i> more than that of <i>analogous</i>). When the average of +cranial characters is considered, both series are best referred to +<i>analogous</i>.</p> + +<p>Hooper (1947:50) pointed out that specimens from the pedregal +San Gerónimo, Distrito Federal, were more nearly black than +topotypes and generally showed less brownish hues typical of +<i>analogous</i>. I have examined this series and several others from this +area (see Specimens examined, <a href="#Page_640">p. 640</a>) and am convinced that +these populations average darker. Actually, the dorsum is more +nearly black and the venter is more buffy than in typical <i>analogous</i>. +The hairs of these individuals average longer than in other populations +of <i>analogous</i>. Skulls of the specimens from the pedregal +are indistinguishable from those of paratypes of <i>analogous</i>. The +populations from the Distrito Federal seem to be incipient subspecies.</p> + +<div class="smaller"> +<a name="FNanchor_1_29" id="FNanchor_1_29"></a> +<a name="FNanchor_2_30" id="FNanchor_2_30"></a> +<a name="FNanchor_3_31" id="FNanchor_3_31"></a> +<a name="FNanchor_4_32" id="FNanchor_4_32"></a> +<a name="FNanchor_5_33" id="FNanchor_5_33"></a> +<a name="FNanchor_6_34" id="FNanchor_6_34"></a> +<a name="FNanchor_7_35" id="FNanchor_7_35"></a> +<a name="FNanchor_8_36" id="FNanchor_8_36"></a> +<a name="FNanchor_9_37" id="FNanchor_9_37"></a> +<a name="FNanchor_10_38" id="FNanchor_10_38"></a> +<p><i>Specimens examined.</i>—Total 696, all from the Republic of México, +distributed as follows: <span class="smcap">San Luis Potosí</span>: +Hacienda Capulín, 5<a href="#Footnote_5_33" class="fnanchor">[33]</a>; +<i>3.3 mi. N Tamazunchale, by-road</i>, 2<a href="#Footnote_6_34" class="fnanchor">[34]</a>; +1 mi. N Tamazunchale, 700 ft., 1<a href="#Footnote_7_35" class="fnanchor">[35]</a>. +<span class="smcap">Veracruz</span>: Acultzingo, 4<a href="#Footnote_1_29" class="fnanchor">[29]</a>, +1<a href="#Footnote_3_31" class="fnanchor">[31]</a>. +<span class="smcap">Jalisco</span>: 1 mi. S Jalostotitlán, 5700 ft., 5; +7 mi. NW Tepatitlán, 3<a href="#Footnote_1_29" class="fnanchor">[29]</a>; +<i>6 mi. N, 4 mi. E Tepatitlán</i>, 6400 ft., 25; <i>2<sup>1</sup>/<sub>2</sub> mi. E Tepatitlán</i>, 6200 ft., 15; +<i>2 mi. S, <sup>1</sup>/<sub>2</sub> mi. W Tepatitlán</i>, 9; <i>near Tepatitlán</i>, 2; +<i>5 mi. SW Arrandas</i>, 6700 ft., 6; <i>2 mi. E Zapotlanejo</i>, 23; +<i>2<sup>1</sup>/<sub>2</sub> mi. E Puente Grande</i> (<i>5<sup>1</sup>/<sub>2</sub> mi. SW Zapotlanejo</i>), 3; +<i>8 mi. S Guadalajara</i>, 10<a href="#Footnote_1_29" class="fnanchor">[29]</a>; +<i>3 mi. ENE Santa Cruz de las Flores</i>, 9; <i>4 mi. NE Ocotlán</i>, 5050 ft., 18; +<i>13 mi. S, 9<sup>1</sup>/<sub>2</sub> mi. W Guadalajara</i>, 1; <i>2 mi. WNW Ocotlán</i>, 5000 ft., 15; +13 mi. S, 15 mi. W Guadalajara, 2; <i>Ocotlán</i>, 5000 ft., +8<a href="#Footnote_2_30" class="fnanchor">[30]</a>; <i>1 mi. S Ocotlán</i>, 5000 ft., 12; +27 mi. S, 12 mi. W Guadalajara, 9; <i>1<sup>1</sup>/<sub>2</sub> mi. N Mazatmitla</i>, +6<a href="#Footnote_1_29" class="fnanchor">[29]</a>; <i><sup>1</sup>/<sub>2</sub> mi. NW Mazatmitla</i>, 4; +<i>3 mi. WSW Mazatmitla</i>, 4; 2 mi. N Ciudad Guzmán, 5000 ft., 18. +<span class="smcap">Guanajuato</span>: 4 mi. N, 5 mi. W León, 7000 ft., 25; +5 mi. S Salamanca, 2<a href="#Footnote_1_29" class="fnanchor">[29]</a>; <i>5 mi. E Celaya</i>, 6000 ft., 6; +<i>1 mi. E Yuriria</i>, 5725 ft., 3; Salvatierra, 5775 ft., 8; <i>NE edge Acambaro</i>, 6050 ft., 10; +<i>Acambaro</i>, 3<a href="#Footnote_2_30" class="fnanchor">[30]</a>. +<span class="smcap">Querétaro</span>: Tolimán, 7<a href="#Footnote_2_30" class="fnanchor">[30]</a>; +6 mi. E Querétaro, 6550 ft., 37. <span class="smcap">Hidalgo</span>: Tula, 2050 m., +1<a href="#Footnote_3_31" class="fnanchor">[31]</a>. <span class="smcap">Michoacán</span>: +<i>2 mi. E La Palma, SE side Lago de Chapala</i>, 7; type locality, 4000 ft., +10<a href="#Footnote_2_30" class="fnanchor">[30]</a> (including the type); +<i>9 mi. E Zamora</i> (<i>Camenaro</i>), 2<a href="#Footnote_1_29" class="fnanchor">[29]</a>; +<i>1 mi. S, 11 mi. W Zamora</i>, 5400 ft., 17; S Cuitzeo, 36<a href="#Footnote_1_29" class="fnanchor">[29]</a>; +<i>Jiquilpan</i>, 4800 ft., 15; <i>11 mi. W Jiquilpan</i>, 6700 ft., 2; <i>1 mi. E Jiquilpan</i>, 7; +<i>1 mi. E Zinapecuaro</i>, 6300 ft., 17; <i>4<sup>1</sup>/<sub>2</sub> mi. NE Tarequato</i> (<i>Tarecuato</i>), 6600 ft, 1; +<i>Tanganciguaro</i> (<i>Tangancicuaro</i>), 5500 ft., 4; <i>2 mi. N Tarecuato</i>, 7200 ft., 1; +<i>2 mi. S Maravatio</i>, 6650 ft, 6; <i>2 mi. SE Zacapu</i>, 6600 ft., 11; +<i>1 mi. N Tinquindin</i> (<i>Tinguindin</i>), 6300 ft., 2; <i>3 mi. E Morelia</i>, 6600 ft., 3; +<i>11 mi. E, 2 mi. S Morelia</i>, 1; 2 mi. SE Hidalgo (Villa Hidalgo), 6; <i>1<sup>1</sup>/<sub>2</sub> mi. N Los Reyes</i>, 1; +<i>E Los Reyes</i>, 18<a href="#Footnote_1_29" class="fnanchor">[29]</a>; +<i>Los Reyes</i>, 8<a href="#Footnote_2_30" class="fnanchor">[30]</a>; +<i>3 mi. W, 1 mi. N Pátzucuaro</i>, 6600 ft., 2; <i>N Pátzucuaro</i>, +2<a href="#Footnote_1_29" class="fnanchor">[29]</a>; <i>Pátzucuaro</i> +9<a href="#Footnote_3_31" class="fnanchor">[31]</a>, 4<a href="#Footnote_2_30" class="fnanchor">[30]</a>, +4<a href="#Footnote_1_29" class="fnanchor">[29]</a>; +Uruapan, 1<a href="#Footnote_1_29" class="fnanchor">[29]</a>; <i>E Uruapan</i>, 12; +<i>2<sup>1</sup>/<sub>2</sub> mi. E Uruapan</i> (<i>La Presca</i>), 2<a href="#Footnote_1_29" class="fnanchor">[29]</a>; +2 mi. SW Zitacuaro, 1; 1 mi. E, 6 mi. S Tacámbaro, 4000 ft., +11<a href="#Footnote_9_37" class="fnanchor">[37]</a>; <i>La Huacana</i>, +1<a href="#Footnote_2_30" class="fnanchor">[30]</a>. <span class="smcap">Mexico</span>: +Templo del Sol, Pyramídes de San Juan, +<span class="pagenum2"><a name="Page_640" id="Page_640">[Pg 640]</a></span> +Teotihuacán, 8000 ft., 1; <i>31 km. E México City</i>, 7500 ft., +11<a href="#Footnote_8_36" class="fnanchor">[36]</a>; <i>17 km. E México City</i>, 7500 ft, +1<a href="#Footnote_8_36" class="fnanchor">[36]</a>; <i>Cerro La Caldera, 11 mi. ESE México</i>, 2350 m., 5; +4 km. ENE Tlalmanalco, 2290 m., 9; <i>Hacienda Córdoba</i> (<i>Córdova</i>), 6. +<span class="smcap">Mexico</span>, D. F.: <i>Cerro de la Estrella, Ixtapalapa</i>, 2450 m., 1; +<i><sup>3</sup>/<sub>4</sub> mi. S, 1 mi. E Churubusco</i>, 2400 m., 2; <i>5 km. S México City, South of Cd. +Universitaria</i>, l<a href="#Footnote_4_32" class="fnanchor">[32]</a>; +<i>Pedregal San Angel</i>, <i>2.6 mi. S Monumento a Obregón, 2</i>; +<i>El Pedregal, 1 km. S San Angel</i>, 2260 m., 1; <i>Falda SW Cerro Zacatepec, +3.9 mi. SW Monumento a Obregón</i>, 1; <i>2 mi. N Tlalpan, Zacayuca</i>, 2380 m., 5; +<i>Tlalpan</i> (<i>Pedregal</i>), 2400 m., 21<a href="#Footnote_3_31" class="fnanchor">[31]</a>; +<i>San Gerónimo</i>, 37<a href="#Footnote_1_29" class="fnanchor">[29]</a>, +6<a href="#Footnote_10_38" class="fnanchor">[38]</a>; <i>Santa Rosa</i>, 2700 m., +1<a href="#Footnote_4_32" class="fnanchor">[32]</a>; <i>Tlalpan</i>, 8; +<i><sup>3</sup>/<sub>4</sub> mi. SW Las Fuentes, Tlalpan</i>, 2450 m., 25<a href="#Footnote_2_30" class="fnanchor">[30]</a>; +<i>Tepepán</i>, 6<a href="#Footnote_1_29" class="fnanchor">[29]</a>; <i>Rancho La Noria, 1 mi. W +Xochimilco</i>, 2270 m., 4; <i>500 meters N Xochitepec</i>, 2250 m., 7; +200 m. N San Mateo Xalpa (Jalpa), 2390 m., 2.</p> + +<p><i>Marginal records.</i>—<span class="smcap">San Luis Potosí</span>: Hacienda Capulín; +1 mi. N Tamazunchale. <span class="smcap">Hidalgo</span>: Tula, 2050 m. +<span class="smcap">Mexico</span>: Templo del Sol, Pyramídes de San Juan, Teotihuacán. +<span class="smcap">Veracruz</span>: Acultzingo. <span class="smcap">Mexico</span>: +4 km. ENE Tlalmanalco. <span class="smcap">Mexico, D. F.</span>: 200 m. N San Mateo Xalpa (Jalpa), 2390 m. +<span class="smcap">Michoacán</span>: 2 mi. SW Zitacuaro; 1 mi. E, 6 mi. S Tacámbaro; Uruapan. +<span class="smcap">Jalisco</span>: 2 mi. N Ciudad Guzmán; 27 mi. S, 12 mi. W Guadalajara; 13 mi. +S, 15 mi. W Guadalajara; 7 mi. NW Tepatitlán; 1 mi. S Jalostotitlán, 5700 ft. +<span class="smcap">Guanajuato</span>: 4 mi. N, 5 mi. W León. <span class="smcap">Querétaro</span>: +6 mi. E Querétaro, 6550 ft.; Tolimán.</p> +</div> + +<div class="footnote"><p><a name="Footnote_1_29" id="Footnote_1_29"></a> +<a href="#FNanchor_1_29"><span class="label">[29]</span></a> Univ. Michigan, Museum of Zoology.</p></div> + +<div class="footnote"><p><a name="Footnote_2_30" id="Footnote_2_30"></a> +<a href="#FNanchor_2_30"><span class="label">[30]</span></a> U. S. Nat. Museum (Biol. Surv. Coll.).</p></div> + +<div class="footnote"><p><a name="Footnote_3_31" id="Footnote_3_31"></a> +<a href="#FNanchor_3_31"><span class="label">[31]</span></a> Chicago Natural History Museum.</p></div> + +<div class="footnote"><p><a name="Footnote_4_32" id="Footnote_4_32"></a> +<a href="#FNanchor_4_32"><span class="label">[32]</span></a> American Museum of Natural History.</p></div> + +<div class="footnote"><p><a name="Footnote_5_33" id="Footnote_5_33"></a> +<a href="#FNanchor_5_33"><span class="label">[33]</span></a> Museum of Natural History, Louisiana State University.</p></div> + +<div class="footnote"><p><a name="Footnote_6_34" id="Footnote_6_34"></a> +<a href="#FNanchor_6_34"><span class="label">[34]</span></a> Univ. Illinois, Mus. Nat. History.</p></div> + +<div class="footnote"><p><a name="Footnote_7_35" id="Footnote_7_35"></a> +<a href="#FNanchor_7_35"><span class="label">[35]</span></a> The Museum, Michigan State Univ.</p></div> + +<div class="footnote"><p><a name="Footnote_8_36" id="Footnote_8_36"></a> +<a href="#FNanchor_8_36"><span class="label">[36]</span></a> Texas A & M, Cooperative Wildlife Research Collection.</p></div> + +<div class="footnote"><p><a name="Footnote_9_37" id="Footnote_9_37"></a> +<a href="#FNanchor_9_37"><span class="label">[37]</span></a> Univ. California, Mus. Vert. Zoology.</p></div> + +<div class="footnote"><p><a name="Footnote_10_38" id="Footnote_10_38"></a> +<a href="#FNanchor_10_38"><span class="label">[38]</span></a> University of Florida Collections.</p></div> + + +<div class="caption3"><a name="Baiomys_taylori_ater" id="Baiomys_taylori_ater"></a> +<b>Baiomys taylori ater</b> (Blossom and Burt)</div> + +<div class="species_ref"><i>Baiomys taylori ater</i> Blossom and Burt, Occas. Papers Mus. Zool., Univ. +Michigan, 465:2, October 8, 1942; Blair and Blossom, Contrib. Lab. +Vert. Biol., Univ. Michigan, 40:1, March, 1948; Hoffmeister and Goodpaster, +Ill. Biol. Monogr., 24(1):115, December 31, 1954; Miller and +Kellogg, Bull. U. S. Nat. Mus., 205:511, March 3, 1955; Hoffmeister, +Amer. Midland Nat., 55:281, April, 1956; Packard, Jour. Mamm., 40:146, +February 20, 1959; Hall and Kelson, The Mammals of North America, +2:659, March 31, 1959 (part).</div> + +<div class="species_ref"><i>Peromyscus taylori paulus</i>, Osgood, N. Amer. Fauna, 28:256, April 17, +1909 (part).</div> + +<div class="species_ref"><i>Baiomys taylori</i> [<i>ater</i>], Justice, Jour. Mamm., 38:520, November 20, 1957.</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult male, skin and skull; No. 85425, University of Michigan, +Museum of Zoology; 7 mi. W Hereford, Cochise County, Arizona, obtained +on March 25, 1941, by Philip M. Blossom, original number 2195.</p> + +<p><i>Range.</i>—Southeastern Arizona, north to Graham County, thence east to +the Animas Valley, Hidalgo County, New Mexico; south to northern Chihuahua +and northwest to the southern border of Cochise County, Arizona, +see <a href="#fig11">Figure 11</a>. Zonal range: largely lower Sonoran (Apachian Biotic Province +of Dice, 1943:56). Occurs from 4300 feet in Chihuahua up to 6200 feet in +New Mexico.</p> + +<p><i>Diagnosis.</i>—Size medium for the species; dorsum between Mummy Brown +and Prouts Brown; individual tips of hairs intermixture of black and Ochraceous-Tawny, +bases of all hairs slate-gray; sides of body and face, Buffy +Brown to Cinnamon Brown; belly Cinnamon Buff, proximal half of individual +hairs Deep Neutral Gray, distal half white; in region of throat, proximal +<span class="pagenum2"><a name="Page_641" id="Page_641">[Pg 641]</a></span> +fourth of individual hairs gray, distal three-fourths white; dorsal vibrissae +black to base, ventral vibrissae white to base; tail brownish above, gray below; +dorsal and ventral surface of forefeet and hind feet buffy to gray; interparietal +somewhat compressed anteroposteriorly. Average and extreme cranial +measurements of 15 adults from 9<sup>1</sup>/<sub>2</sub> mi. W New Mexico State Line, 5<sup>1</sup>/<sub>2</sub> mi. N +Mexican border, Cochise County, Arizona, are as follows: occipitonasal +length, 18.0 (17.5-18.6); zygomatic breadth, 9.5 (9.2-9.9); postpalatal length, +6.6 (6.0-7.1); least interorbital breadth, 3.6 (3.4-3.8); length of incisive +foramina, 4.0 (3.8-4.2); length of rostrum, 6.1 (5.7-6.4); breadth of braincase, +8.6 (8.4-9.1); depth of cranium, 6.5 (6.3-6.9); alveolar length of maxillary +tooth-row, 3.2 (3.1-3.4). Average and extreme external measurements for +six adults from 9 mi. W Hereford, Cochise County, are as follows: total +length, 106.3 (98-115); length of tail vertebrae, 42.3 (39-46); length of body, +64 (59-69); length of hind foot, 13.6 (13-14.2); length of ear from notch, +11.1 (10.5-11.5); for photographs of skull, see <a href="#plate2">Plate 2<i>b</i></a>, +and <a href="#plate4">Plate 4<i>c</i></a>.</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. t. canutus</i>, see account of that +subspecies. From <i>B. t. paulus</i>, the subspecies to the southeast, <i>B. t. ater</i> +differs in: dorsum darker brown; tail less strikingly bicolored; belly buffy +rather than whitish to white-gray; forefeet and hind feet darker dorsally and +ventrally; posterior margin of basioccipital bowed anteriorly in a broad U-shape +with a secondary small median anteriorly directed U-shaped curve, rather +than bowed anteriorly in a simple U-shape; interparietal more compressed +anteroposteriorly; coronoid process of mandible so acutely recurved that tip +of coronoid points posteroventrally and appears sickle-shaped.</p> +</div> + +<p><i>Remarks.</i>—Blossom and Burt (1942:1) described <i>B. t. ater</i> as the +darkest of the known subspecies. It is dark, but specimens from +some parts of the ranges of <i>B. t. analogous</i>, <i>B. t. fuliginatus</i>, and +<i>B. t. subater</i> exceed in melanins the darkest individuals of <i>ater</i>. +Blair and Blossom (1948:5) also concluded by the use of an Ives +tint photometer that <i>B. t. subater</i> was significantly darker than <i>B. t. +ater</i>.</p> + +<p>When paratypes of <i>ater</i> and specimens of <i>B. t. paulus</i> are compared, +the darkest individuals of <i>ater</i> exceed but slightly the darkest +of <i>paulus</i>. The darkest specimens of <i>paulus</i> occur in southern +Zacatecas, and northern Jalisco, and the palest of the series are in +northern Durango and southern Chihuahua. When paratypes of +<i>ater</i> and <i>paulus</i> are compared, the difference in color is readily +distinguishable. Specimens from 1<sup>1</sup>/<sub>2</sub> mi. N San Francisco, in northern +Chihuahua, appear to be intermediate in color between <i>ater</i> +and <i>paulus</i> except for a faint tinge of buff ventrally. In characters +of the crania, these specimens resemble <i>ater</i> and are referred to +that subspecies. A slightly different pattern of color is present +in pygmy mice from the Peloncillo Mountains and the Animas +Valley of New Mexico; the upper parts resemble those of paratypes +of <i>ater</i>, but the venter has only the faintest suggestion of the +<span class="pagenum"><a name="Page_642" id="Page_642">[Pg 642]</a></span> +buffy wash. Crania of these specimens from New Mexico are +inseparable from those of paratypes of <i>ater</i>, and the specimens +are, therefore, referred to <i>ater</i>.</p> + +<p>When specimens are arranged by localities from Arizona east +into southern New Mexico, thence south into Chihuahua and +Durango, gradual intergradation in color is evident from dark +in the north to pale browns in the south, whereas, size and shape +of interparietal and size and shape of coronoid process of the lower +jaw divide quite distinctly into two morphological types in central +Chihuahua.</p> + +<p>Cranial variation in size and proportion among adults is slight +throughout the range of <i>ater</i> compared to variation detected in +other subspecies of <i>Baiomys taylori</i>. Perhaps such a relatively +stable pattern of characters of the crania reflects the homogeneity +of the gene pool, with respect to these characters, of the populations +sampled. The fact that the color of the pelage of this subspecies +varies considerable throughout its known range and that the +crania do not is perhaps a clue to the mode of inheritance of +characters in these mice. Seemingly, color of pelage is inherited +independently of characters of the cranium. The relative lack of +variability in the crania of <i>ater</i> may result from uniform environmental +conditions, which have served to select for uniform characters +in the populations. All of the other wide-ranging subspecies +of <i>B. taylori</i> occupy more diverse habitats than <i>ater</i>. Secondly, +the rather abrupt change in the cline of measured characters of +the crania between <i>ater</i> and <i>paulus</i> in central Chihuahua suggests +a secondary zone of intergradation. The probable cessation of +gene flow in the past between these two subspecies, allowing <i>ater</i> +to be isolated for a time, may also, in part, account for the relative +lack of variability in the crania of <i>ater</i>.</p> + +<div class="smaller"> +<a name="FNanchor_1_39" id="FNanchor_1_39"></a> +<a name="FNanchor_2_40" id="FNanchor_2_40"></a> +<a name="FNanchor_3_41" id="FNanchor_3_41"></a> +<a name="FNanchor_4_42" id="FNanchor_4_42"></a> +<a name="FNanchor_5_43" id="FNanchor_5_43"></a> +<p><i>Specimens examined.</i>—Total 58, distributed as follows: +<span class="smcap">Arizona</span>: <i>Graham County</i>: 1<sup>1</sup>/<sub>2</sub> mi. SW Ft. Grant, Graham Mts., +1<a href="#Footnote_1_39" class="fnanchor">[39]</a>; <i>Pima County</i>: 1<sup>1</sup>/<sub>2</sub> mi. ENE +Greaterville, Thurber Ranch, 2<a href="#Footnote_1_39" class="fnanchor">[39]</a>; +<i>Santa Cruz County</i>: Patagonia, 3<a href="#Footnote_1_39" class="fnanchor">[39]</a>; +<i>Cochise County</i>: <i>9 mi. W Hereford</i>, 10<a href="#Footnote_5_43" class="fnanchor">[43]</a>; +type locality, 2<a href="#Footnote_5_43" class="fnanchor">[43]</a> (including the type); +<i>5 mi. W Hereford</i>, 5<a href="#Footnote_5_43" class="fnanchor">[43]</a>; +9<sup>1</sup>/<sub>2</sub> mi. W New Mexico State Line, 5<sup>1</sup>/<sub>2</sub> mi. N Mexican border, +20<a href="#Footnote_4_42" class="fnanchor">[42]</a>; <i>3 mi. E, 1 mi. N Chiricahua</i>, +1<a href="#Footnote_4_42" class="fnanchor">[42]</a>. <span class="smcap">New Mexico</span>: +<i>Hidalgo County</i>: 18 mi. S, 2 mi. W Animas, 2; <i>22 mi. S, 2 mi. W Rodeo</i>, 6000 ft., +1<a href="#Footnote_2_40" class="fnanchor">[40]</a>; <i>22 mi. S, 2 mi. E Rodeo</i>, 6000 ft., +3<a href="#Footnote_2_40" class="fnanchor">[40]</a>; 25<sup>1</sup>/<sub>2</sub> mi. S Animas, 6200 ft. (in Big Bill Canyon), +1<a href="#Footnote_2_40" class="fnanchor">[40]</a>. <span class="smcap">Chihuahua</span>: +<i>5<sup>1</sup>/<sub>2</sub> mi. N, 2 mi. W San Francisco</i>, 5100 ft., 1; <i>2<sup>1</sup>/<sub>2</sub> mi. N, 3 mi. W San Francisco</i>, +5200 ft., 1; 1<sup>1</sup>/<sub>2</sub> mi. N San Francisco, 5100 ft., 4; Casas Grandes, 4300 ft., +1<a href="#Footnote_3_41" class="fnanchor">[41]</a>.</p> + +<p><i>Marginal records></i>—<span class="smcap">Arizona</span>: 1<sup>1</sup>/<sub>2</sub> mi. SW Ft. Grant, Graham Mts. +<span class="smcap">New Mexico</span>: 18 mi. S, 2 mi. W Animas; 25<sup>1</sup>/<sub>2</sub> mi. S Animas (in Big Bill Canyon). +<span class="smcap">Chihuahua</span>: 1<sup>1</sup>/<sub>2</sub> mi. N San Francisco; Casas Grandes. +<span class="smcap">Arizona</span>: Patagonia; 1<sup>1</sup>/<sub>2</sub> mi. ENE Greaterville, Thurber Ranch.</p> +</div> + +<div class="footnote"><p><a name="Footnote_1_39" id="Footnote_1_39"></a> +<a href="#FNanchor_1_39"><span class="label">[39]</span></a> University of Illinois, Museum of Natural History.</p></div> + +<div class="footnote"><p><a name="Footnote_2_40" id="Footnote_2_40"></a> +<a href="#FNanchor_2_40"><span class="label">[40]</span></a> University of New Mexico.</p></div> + +<div class="footnote"><p><a name="Footnote_3_41" id="Footnote_3_41"></a> +<a href="#FNanchor_3_41"><span class="label">[41]</span></a> U. S. Nat. Museum (Biol. Surv. Coll.).</p></div> + +<div class="footnote"><p><a name="Footnote_4_42" id="Footnote_4_42"></a> +<a href="#FNanchor_4_42"><span class="label">[42]</span></a> University of Arizona.</p></div> + +<div class="footnote"><p><a name="Footnote_5_43" id="Footnote_5_43"></a> +<a href="#FNanchor_5_43"><span class="label">[43]</span></a> Univ. Michigan, Museum of Zoology.</p> + +<p><span class="pagenum"><a name="Page_643" id="Page_643">[Pg 643]</a></span></p></div> + + +<div class="caption3"><a name="Baiomys_taylori_canutus" id="Baiomys_taylori_canutus"></a> +<b>Baiomys taylori canutus</b>, new subspecies</div> + +<div class="species_ref"><i>Peromyscus taylori paulus</i>, Osgood, N. Amer. Fauna, 28:255, April 17, 1909 +(part).</div> + +<div class="species_ref"><i>Peromyscus musculus</i> [<i>musculus</i>], Osgood, N. Amer. Fauna, 28:256, April +17, 1909 (part).</div> + +<div class="species_ref"><i>Baiomys taylori paulus</i>, Miller, Bull. U. S. Nat. Mus., 79:137, December 31, +1912 (part); Miller, Bull. U. S. Nat. Mus., 128:317, April 29, 1924 +(part); Burt, Miscl. Publ., Mus. Zool., Univ. Michigan, 39:54, February +14, 1938; Goldman, Smith. Miscl. Coll., 115:373, July 31, 1951 (part); +Miller and Kellogg, Bull. U. S. Nat. Mus., 205:512, March 3, 1955 (part); +Hooper, Occas. Papers Mus. Zool., Univ. Michigan, 565:13, March 31, +1955; Hall and Kelson, The Mammals of North America, 2:659, March +31, 1959 (part).</div> + +<div class="species_ref"><i>Baiomys musculus musculus</i>, Goldman, Smith. Miscl. Coll., 115:336, July +31, 1951 (part).</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult male, skin and skull; No. 62075, University of Kansas, +Museum of Natural History; 1 mi. S Pericos, Sinaloa, Republic of México; +obtained on June 14, 1954, by A. A. Alcorn, original number 1754.</p> + +<p><i>Range.</i>—Central Nayarit northward through western Sinaloa, to as far +north as south-central Sonora, see <a href="#fig11">Figure 11</a>. Zonal range: Lower arid +tropical, closely approximating the Sinaloan Biotic Province of Goldman and +Moore (1945:349). Occurs from near sea level at Escuinapa (43 feet), +Sinaloa, to 3200 feet at a place 2 mi. WNW Tepic, Nayarit.</p> + +<p><i>Diagnosis.</i>—Dorsal ground color Buffy Brown (some specimens near Olive +Brown); proximal fourth of individual guard hairs of dorsum black-tipped, +distal three-fourths dark grayish; dorsal underfur black-tipped having subterminal +band of Buffy Brown; hair around eyes buffy to base; belly Pallid +Neutral Gray with overtones of buff; individual hairs in region of chin whitish-gray +to bases; vibrissae blackish to bases except ventralmost, those being +white to base; tail Dark Olive above, slightly paler below. Average and +extreme external measurements of 13 adults from 15 mi. N Rosario, Chelé, +Sinaloa, 300 ft., are as follows: Total length, 109.6 (99-120); length of +tail, 43.4 (38-49); length of body, 66.2 (58-75); length of hind foot, 11.2 +(10-12). Average and extreme cranial measurements of 19 adults from the +same place are as follows: occipitonasal length, 18.2 (17.7-18.9); zygomatic +breadth, 9.6 (9.2-10.1); postpalatal length, 6.9 (6.5-7.3); least interorbital +breadth, 3.6 (3.4-3.8); length of incisive foramina, 3.9 (3.5-4.2); length of +rostrum, 5.9 (5.5-6.6); breadth of braincase, 8.7 (8.3-8.9); depth of cranium, +6.5 (6.2-6.7); alveolar length of maxillary tooth-row, 3.1 (3.0-3.2); breadth +of zygomatic plate, 1.8 (1.6-2.0); for photographs of skull, see <a href="#plate2">Plate 2<i>c</i></a>, and +<a href="#plate4">Plate 4<i>d</i></a>.</p> + +<p><i>Comparisons.</i>—From <i>B. t. ater</i>, <i>B. t. canutus</i> differs in: dorsum slightly +grayer; belly whitish to pale-gray with only faint tones of buff, rather than +cinnamon-buff to buff-gray; forefeet and hind feet flesh-colored to grayish +above instead of whitish to flesh-colored; tail paler above, less hairy, scales +more evident; interparietal relatively larger from anteriormost to posteriormost +points; incisive foramina tapering less abruptly posteriorly, not constricted +towards midline; over-all size of body and cranium somewhat larger.</p> + +<p>From <i>B. t. paulus</i>, <i>B. t. canutus</i> differs in: dorsum grayish-brown rather +than fawn-colored (not differing appreciably from extremes of darker brown +specimens of <i>paulus</i>); forefeet and hind feet flesh-colored to grayish above +<span class="pagenum2"><a name="Page_644" id="Page_644">[Pg 644]</a></span> +rather than white above; tail less hairy, unicolored to faintly bicolored rather +than distinctly bicolored; braincase slightly larger; alveolar length of maxillary +tooth-row slightly less.</p> + +<p>From <i>B. t. analogous</i>, <i>B. t. canutus</i> differs in: dorsum paler, less of dark +brown hues; belly paler; forefeet and hind feet slightly paler, less sooty +above; tail less hairy, paler and having scales evident; jugal of zygoma extending +ventrally to a point immediately above, instead of below, level of alveolus +of upper molars; nasals more nearly truncate anteriorly; infraorbital foramina +less deeply notched toward midline of skull; body and skull averaging smaller +throughout.</p> + +<p>From <i>B. t. allex</i>, <i>B. t. canutus</i> differs in: dorsal ground color grayish rather +than fawn color having grayish overtones; underfur on dorsum darker gray; +dorsal surface of forefeet and hind feet flesh-colored to grayish rather than +flesh-colored; incisive foramina tapering to a point posteriorly rather than +rounded posteriorly; interparietal relatively smaller; body and skull averaging +larger throughout.</p> +</div> + +<p><i>Remarks.</i>—Burt (1938:54) reluctantly assigned specimens from +Ciudad Obregón to <i>B. t. paulus</i>, probably being influenced by the +resemblance in size. He suggested that, perhaps, a distinct subspecies +occurs in the State of Sonora. Study of larger series of +specimens than were available to Burt reveals that populations of +pygmy mice inhabiting the northwest coastal plains of México are +indeed distinct.</p> + +<p>The darkest of the material assigned to <i>canutus</i> is from Nayarit +(for specific localities see specimens examined). According to +Tamayo (1949:Carta de Suelos), color of soil changes from chestnut +in northern Sinaloa to black in southern Sinaloa and northern +Nayarit. There seems, therefore, to be a close correlation between +color of pelage and color of soil in this area. In Nayarit, particularly +in the central and southern parts, the mice are intermediate in color +between the paler, grayer population to the north and the more +brownish samples, representative of <i>allex</i> to the south. The coastal +vegetation changes from the arid tropical thorn forests of the north +and central parts of Sinaloa to a savannah in Nayarit, thence to a +tropical deciduous forest farther south (see Leopold, 1950:508).</p> + +<p>In size and color, specimens from 3 mi. SE Tepic and 2 mi. SW +Rosa Morada are intermediate between the larger, grayer <i>canutus</i> +and the smaller, light-brownish <i>allex</i>. In size of cranium, these +specimens are more nearly like <i>canutus</i>, and are referred to that +subspecies. Mice from the western coastal plain are relatively +homogeneous as regards size of body and skull, except that those +from 13.5 mi. S Acaponéta, Nayarit, average somewhat larger.</p> + +<p><i>B. t. canutus</i>, like <i>B. t. subater</i>, is predominantly a lowland or +coastal subspecies. The pallor of the former, that lives on generally +paler soils, presumably is of adaptive value.</p> + +<p><span class="pagenum"><a name="Page_645" id="Page_645">[Pg 645]</a></span></p> + +<p>Pygmy mice are seemingly rare in the northern part of the range +of this subspecies. J. Raymond Alcorn and Albert Alcorn were +successful in collecting only two specimens from the type locality +after three successive nights of trapping with 100 traps set each +night. Only six specimens are known from Sonora. These were +obtained in the irrigated regions of Ciudad, Obregón, and Navajoa. +Charles Sibley obtained one specimen 10.6 mi. SE Ciudad Obregón +in a "maguey field." I obtained one specimen 1 mi. NNW Navajoa +in a sparse grassway, 20 feet wide, bordering an open sewer, which +coursed northward into the Río Mayo. Irrigated wheat fields bordered +the grassway and ditch.</p> + +<div class="smaller"> +<a name="FNanchor_1_44" id="FNanchor_1_44"></a> +<a name="FNanchor_2_45" id="FNanchor_2_45"></a> +<a name="FNanchor_3_46" id="FNanchor_3_46"></a> +<a name="FNanchor_4_47" id="FNanchor_4_47"></a> +<a name="FNanchor_5_48" id="FNanchor_5_48"></a> +<a name="FNanchor_6_49" id="FNanchor_6_49"></a> +<p><i>Specimens examined.</i>—Total 70 all from the Republic of México and distributed +as follows: <span class="smcap">Sonora</span>: [Ciudad] Obregón, +4<a href="#Footnote_1_44" class="fnanchor">[44]</a>; 10.6 mi. SE [Ciudad] +Obregón, 1<a href="#Footnote_2_45" class="fnanchor">[45]</a>; 1 mi. NNW Navajoa, 1. +<span class="smcap">Sinaloa</span>: type locality, 2 (including the type); +Culiacán, 175 ft., 2<a href="#Footnote_3_46" class="fnanchor">[46]</a>; +Mazatlán, 1<a href="#Footnote_5_48" class="fnanchor">[48]</a>; <i>15 mi. N Rosario, Chelé</i>, 300 ft., +35<a href="#Footnote_4_47" class="fnanchor">[47]</a>; +Rosario, 3<a href="#Footnote_3_46" class="fnanchor">[46]</a>; +Escuinapa, 5<a href="#Footnote_5_48" class="fnanchor">[48]</a>; +<i>Railroad Station Escuinapa</i>, 43 ft., 2<a href="#Footnote_2_45" class="fnanchor">[45]</a>. +<span class="smcap">Nayarit</span>: Acaponéta, 4<a href="#Footnote_3_46" class="fnanchor">[46]</a>; +<i>13.5 mi. S Acaponéta Junction</i>, 6<a href="#Footnote_6_49" class="fnanchor">[49]</a>; +2 mi. SW Rosa Morada, 2; <i>2 mi. WNW Tepic</i>, 3200 ft., 1; 3 mi. SE Tepic, 1.</p> + +<p><i>Marginal records.</i>—<span class="smcap">Sonora</span> [Ciudad] Obregón. <span class="smcap">Sinaloa</span>: type locality; +Escuinapa. <span class="smcap">Nayarit</span>: Acaponéta; 3 mi. SE Tepic. <span class="smcap">Sinaloa</span>: Mazatlán.</p> +</div> + +<div class="footnote"><p><a name="Footnote_1_44" id="Footnote_1_44"></a> +<a href="#FNanchor_1_44"><span class="label">[44]</span></a> Coll. Univ. California, Los Angeles.</p></div> + +<div class="footnote"><p><a name="Footnote_2_45" id="Footnote_2_45"></a> +<a href="#FNanchor_2_45"><span class="label">[45]</span></a> Univ. California, Mus. Vert. Zoology.</p></div> + +<div class="footnote"><p><a name="Footnote_3_46" id="Footnote_3_46"></a> +<a href="#FNanchor_3_46"><span class="label">[46]</span></a> U. S. Nat. Museum (Biol. Surv. Coll.).</p></div> + +<div class="footnote"><p><a name="Footnote_4_47" id="Footnote_4_47"></a> +<a href="#FNanchor_4_47"><span class="label">[47]</span></a> Univ. Michigan, Museum of Zoology.</p></div> + +<div class="footnote"><p><a name="Footnote_5_48" id="Footnote_5_48"></a> +<a href="#FNanchor_5_48"><span class="label">[48]</span></a> American Museum of Natural History.</p></div> + +<div class="footnote"><p><a name="Footnote_6_49" id="Footnote_6_49"></a> +<a href="#FNanchor_6_49"><span class="label">[49]</span></a> Univ. Illinois, Mus. Nat. History.</p></div> + + +<div class="caption3"><a name="Baiomys_taylori_fuliginatus" id="Baiomys_taylori_fuliginatus"></a> +<b>Baiomys taylori fuliginatus</b>, new subspecies</div> + +<div class="species_ref"><i>Baiomys taylori taylori</i>, Dalquest, Louisiana State Univ. Studies (Biol. +Sci. Ser.) 1:155, December 28, 1953 (part).</div> + +<div class="species_ref"><i>Baiomys taylori taylori</i>, Booth, Walla Walla Publs. Dept. Biol. Sci., 20:15, +July 10, 1957 (part).</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult male, skin and skull; No. 36765, University of Kansas, +Museum of Natural History; 10 mi. E, 2 mi. N Ciudad del Maíz, 4000 ft., San +Luis Potosí, Republic of México; obtained on January 17, 1950, by J. R. +Alcorn, original number 10400.</p> + +<p><i>Range.</i>—Occurs in the Sierra Madre Oriental of the northeastern third of +San Luis Potosí. Zonal range: Upper Tropical (see Dalquest, 1953:10); +approximates a part of the Sierra Madre Oriental Biotic Province of Goldman +and Moore (1945:349, 356). Occurs from 2000 feet at El Salto up to 4000 +feet at Ciudad del Maíz.</p> + +<p><i>Diagnosis.</i>—Size large for the species; ground color of dorsum Chaetura +Drab; individual guard hairs of dorsum black to base, distal fourth of hairs +of underfur in posterior half of dorsum tipped with grayish-brown, proximal +three-fourths Dark Neutral Gray; in anterior region of dorsum, posterior to +ears, distal third of hairs grayish-brown and proximal two-thirds Dark Neutral +Gray to base; sides slightly paler than dorsum; ground color of belly Neutral +Gray, individual hairs of belly and throat tipped with Pallid Neutral Gray, +basally Deep Neutral Gray to Dark Neutral Gray; tips of individual hairs of +face Ochraceous-Tawny; lateral vibrissae whitish, dorsal and ventral vibrissae +black to base; forefeet and hind feet sooty above and below, thigh bearing +<span class="pagenum2"><a name="Page_646" id="Page_646">[Pg 646]</a></span> +some white-tipped hairs; tail near Chaetura Drab above, Pale Neutral Gray +below; anterior part of jugal projecting slightly ventrally and forming small +protuberance at point of articulation with maxillary part of zygoma; jugal +extending anteriorly nearly to lacrimal. In most cranial measurements averaging +as large as <i>B. t. analogous</i>. Average and extreme measurements of the type +and three additional paratypes, all adults, are: total length, 105.5 (101-109); +length of tail, 39.8 (35-42); length of body, 65.8 (63-68); length of hind +foot, 14.3 (14-15); length of ear from notch, 11 (11); occipitonasal length, +18.1 (18.1-18.8); zygomatic breadth, 9.6 (9.3-9.8); postpalatal length, 6.5 +(6.0-6.7); least interorbital breadth, 3.4 (3.3-3.6); length of incisive foramina, +4.0 (3.8-4.2); length of rostrum, 6.3 (6.1-6.4); breadth of braincase, 8.8 +(8.6-8.9); depth of cranium, 6.7 (6.5-6.8); alveolar length of maxillary tooth-row, +3.2 (3.1-3.3); for photograph of skull, see <a href="#plate2">Plate 2<i>d</i></a>, +and <a href="#plate4">Plate 4<i>e</i></a>.</p> + +<p><i>Comparisons.</i>—From <i>B. t. taylori</i>, <i>B. t. fuliginatus</i> differs in: dorsum +slightly darker than in darkest <i>taylori</i>; tail densely haired, bicolored rather +than unicolored; belly sooty to grayish rather than grayish to whitish; forefeet +and hind feet sooty to grayish rather than flesh-colored; incisive foramina +less bowed laterally, more nearly straight; interparietal compressed anteroposteriorly, +less diamond-shaped.</p> + +<p>From <i>B. t. paulus</i>, <i>B. t. fuliginatus</i> differs in: dorsum dusky to blackish +rather than fawn color; belly sooty to grayish rather than buffy to whitish-gray; +forefeet and hind feet sooty to grayish rather than whitish; zygoma +more nearly forming a right angle with rostrum or skull, less tapered anteriorly; +anterior part of jugal possessing ventral projection; jugal extending nearly to +lacrimal on posterior surface of maxillary part of zygoma.</p> + +<p>From <i>B. t. analogous</i>, <i>B. t. fuliginatus</i> differs in: mid-dorsal region blacker, +less brownish; tail distinctly bicolored rather than unicolored to faintly bicolored; +incisive foramina not constricted medially; presphenoid broader (at +narrowest point); jugal differs much the same as it does from <i>paulus</i>; nasals +anteriorly truncate instead of rounded.</p> +</div> + +<p><i>Remarks.</i>—Dalquest (1953:155-157) and Booth (1957:15) assigned +all of the pygmy mice that they examined from the state of +San Luis Potosí to <i>B. t. taylori</i>. Examination of all of the material +that was available to Dalquest, plus additional specimens at the +University of Kansas Museum of Natural History, reveals that +there are three subspecies in San Luis Potosí. <i>B. t. taylori</i> occurs +in the eastern part of the State at lower altitudes; <i>B. t. analogous</i> +occurs to the southeast at higher altitudes; <i>B. t. fuliginatus</i> occurs +in the northeastern part of the State in the Sierra Madre Oriental.</p> + +<p>Specimens obtained from Ebano, Pujal, and Tamuín, representative +of <i>B. t. taylori</i>, are much paler on the belly and on the ventral +surface of the forefeet and hind feet than are specimens from Ciudad +del Maíz, representative of <i>B. t. fuliginatus</i>. The tail in <i>B. t. +taylori</i> is nearly unicolored and less hairy than in the paratypical +series of <i>fuliginatus</i>. Specimens from 4 km. NE Ciudad Valles are +nearly intermediate in color of the belly, dorsum, forefeet and hind +<span class="pagenum"><a name="Page_647" id="Page_647">[Pg 647]</a></span> +feet, and tail, between the palest mice from the coastal plain and +the darker mice in the mountains of the northeastern part of the +State (specimens from El Salto average paler, however, than the +type and paratypes). These specimens seem to be intergrades +between <i>B. t. taylori</i> to the east on the coastal plain and <i>fuliginatus</i> +to the northwest in the mountains. It seems best to refer the mice +from 4 km. N Ciudad Valles to <i>B. t. taylori</i> on the basis of the +average of external and cranial characters. Specimens from 6 mi. +SW San Gerónimo, Coahuila, also referred to <i>B. t. taylori</i>, resemble +in color the mice from 4 km. N Ciudad Valles. When more +specimens are obtained from the front range of the Sierra Madre +Oriental, at lower altitudes, the manner in which these two subspecies +intergrade with one another will be better understood. At +present, populations from higher altitudes in the mountains seem +to represent a dark subspecies; populations from the coastal plain +represent a pale subspecies, and those from the lower slopes and +high valleys seemingly are intergrades. <i>B. t. fuliginatus</i> occurs in a +somewhat limited strip of chernozem soil (or suelos negros of +Tamayo, 1949: Carta de Suelos). The populations occurring at +lower altitudes on the coastal plain are on generally paler soils.</p> + +<div class="smaller"> +<p><i>Specimens examined.</i>—Total 39, all from the Republic of México, as follows: +<span class="smcap">San Luis Potosí</span>: El Salto, 24 Mus. Nat. Hist., Louisiana State Univ., 7 Amer. +Mus. Nat. Hist.; type locality, 8 (including the type).</p> + +<p><i>Marginal records.</i>—See specimens examined.</p> +</div> + + +<div class="caption3"><a name="Baiomys_taylori_paulus" id="Baiomys_taylori_paulus"></a> +<b>Baiomys taylori paulus</b> (J. A. Allen)</div> + +<div class="species_ref"><i>Peromyscus paulus</i>, J. A. Allen, Bull. Amer. Mus. Nat. Hist., 19:598, +November 12, 1903; Elliot, Field Columb. Mus. Publ., 105(6): 136, +July 1, 1905.</div> + +<div class="species_ref"><i>Baiomys taylori paulus</i>, Miller, Bull. U. S. Nat. Mus., 79:137, December 31, +1912 (part); Miller, Bull. U. S. Nat. Mus., 128:317, April 29, 1924 +(part); Ellerman, The Families and Genera of Living Rodents, 2:402, +March 21, 1941 (part); Goldman, Smith, Miscl. Coll., 115:373, July 31, +1951 (part); Hall and Kelson, Univ. Kansas Publs., Mus. Nat. Hist., +26:367, December 15, 1952; Goodwin, Bull. Amer. Mus. Nat. Hist., +102:318, August 31, 1953; Miller and Kellogg, Bull. U. S. Nat. Mus., +205:511, March 3, 1955 (part); Packard, Proc. Biol. Soc. Washington, +71:17, April 11, 1958; Packard, Jour. Mamm., 40:146, February 20, +1959; Hall and Kelson, The Mammals of North America, 2:659, March +31, 1959 (part).</div> + +<div class="species_ref">[<i>Peromyscus</i>] <i>paulus</i>, Elliot, Field Columb, Mus. Publ., 95(4):136, July +15, 1904.</div> + +<div class="species_ref"><i>Peromyscus taylori paulus</i>, Osgood, N. Amer. Fauna, 28:255, April 17, +1909 (part).</div> + +<div class="species_ref"><i>Peromyscus musculus</i> [<i>musculus</i>], Osgood, N. Amer. Fauna, 28:256, April +17, 1909 (part).</div> + +<div class="species_ref"><i>Baiomys taylori</i> [= <i>paulus</i>], Twente and Baker, Jour. Mamm., 32:121, +February 15, 1951.</div> + +<p><span class="pagenum"><a name="Page_648" id="Page_648">[Pg 648]</a></span></p> + +<div class="species_ref"><i>Baiomys musculus musculus</i>, Goldman, Smith. Miscl. Coll., 115:336, July +31, 1951 (part).</div> + +<div class="species_ref"><i>Baiomys taylori allex</i>, Hall and Kelson, The Mammals of North America, +2:659, March 31, 1959 (part).</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult male, skin and skull; No. 21165, American Museum of Natural +History; Río Sestín, Durango, Republic of México; obtained on April 15, 1903, +by J. H. Batty, original number 455.</p> + +<p><i>Range.</i>—Central Chihuahua south through Durango (west to eastern edge +of Sierra Madre Occidental), to Zacatecas and Aguascalientes, thence west +into northern and northwestern Jalisco, see <a href="#fig11">Figure 11</a>. Zonal range: Lower +Sonoran, approximately the Chihuahua Desert Biotic Province of Goldman +and Moore (1945:349). Occurs from 4000 feet 2 mi. ESE Tequila, Jalisco, +up to 6700 feet 2 mi. W Miñaca, Chihuahua.</p> + +<p><i>Diagnosis.</i>—Size medium to small for the species; dorsum Buffy Brown to +fawn color; dorsal ground color of unworn pelage of adults varying from +Buffy Brown in darkest series (especially those from higher altitudes) to +Avellaneous with grayish overtones in palest series; worn pelage in mid-dorsal +region of adults fawn to grayish; terminal parts of individual hairs buffy, gray +basally; guard hairs on dorsum black-tipped, grayish basally; belly Light Gull +Gray, distal half of hairs white, proximal half Neutral Gray; hairs in region +of throat and chin white to base (some specimens with faint buffy overtones); +forefeet dusky below, whitish above; hind feet whitish above, ventral surface +whitish to dusky; dorsal and lateral vibrissae black, other vibrissae white. +Average and extreme measurements of six adults from the type locality are as +follows: total length, 109 (106-117); length of tail, 44.5 (43-48); length of +body, 63 (57-69); length of hind foot, 13.1 (12.7-14.0); occipitonasal length, +17.5 (17.4-18.0); zygomatic breadth, 9.3 (9.1-9.5); postpalatal length, 6.6 +(6.2-6.9); least interorbital breadth, 3.5 (3.4-3.6); length of incisive foramina, +3.8 (3.6-4.1); length of rostrum, 5.9 (5.7-6.0); breadth of braincase, 8.6 +(8.5-8.8); depth of cranium, 6.6 (6.2-6.9); alveolar length of maxillary tooth-row, +3.2 (3.1-3.4); for photographs of the skull, see <a href="#plate2">Plate 2<i>e</i></a> +and <a href="#plate4">Plate 4<i>f</i></a>.</p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. t. allex</i>, <i>B. t. canutus</i>, <i>B. t. ater</i>, and +<i>B. t. taylori</i>, see accounts of those subspecies. From <i>B. t. analogous</i>, <i>B. t. paulus</i> +differs as follows: dorsal color paler having more reddish-brown than blackish-brown +tones; venter whitish to buffy, instead of gray to light-gray; tail +bicolored (not unicolored), usually having more hairs; hind feet white (not +sooty) above. Cranially, <i>B. t. paulus</i> differs from <i>B. t. analogous</i> in: skull +slightly smaller in all dimensions; maxillary part of zygoma narrowing and +forming oblique angle rather than a near right angle with rostrum; anterior +incisive foramina constricted posteriorly; tips of nasals truncate (less rounded).</p> +</div> + +<p><i>Remarks.</i>—J. A. Allen (1903:599) correctly pointed out that +young specimens, in first pelage, were gray brown; young adults +were darker and more varied with some blackish; adults and old +adults were buffy to grayish. The change in color of pelage with +increasing age is more pronounced in <i>paulus</i> than in other subspecies +of <i>B. taylori</i>. Of two males collected on April 12, 1949, one, +an adult, is buffy brown, and the other, an old adult with worn +pelage, is grayish-brown. In mice in the earlier stages of adulthood, +<span class="pagenum"><a name="Page_649" id="Page_649">[Pg 649]</a></span> +underfur of the dorsum is buffy at the tips and gray basally. With +increased wear, the buffy tip is lost. Consequently, mice in the +later stages of adulthood are grayish.</p> + +<p><i>B. t. paulus</i> intergrades with <i>ater</i> to the north in Chihuahua (see +account of that subspecies), with <i>analogous</i> to the south in Jalisco, +and with <i>allex</i> (see account of that subspecies) to the southwest in +Nayarit and Jalisco. The zone of intergradation between <i>paulus</i> +and <i>analogous</i> in Jalisco approximately borders the Río Grande de +Santiago from the western part of the State to the northwest shore +of Lago de Chapala. Nineteen specimens from 2 mi. WNW Lagos +de Moreno in northwest Jalisco seem to be intermediate between +<i>paulus</i> and <i>analogous</i> in color, averaging slightly grayer than typical +<i>paulus</i>. The series of 19 is referable to <i>paulus</i> on the basis of cranial +characters.</p> + +<p>A series of 34 specimens from 3 mi. W La Venta, Jalisco (referable +to <i>paulus</i>), is indistinguishable in color of pelage from two series +of <i>paulus</i> from 5 mi. N Durango, and from 8 mi. NE of Durango, +except that the antiplantar surfaces of the hind feet are sooty as in +<i>analogous</i>. Seemingly, features of color mentioned above as diagnostic +of the two subspecies are either present or absent and there +is no tendency toward intermediacy in color in the population from +3 mi. W La Venta.</p> + +<p>The Río Grande de Santiago may have acted in the past as a +physical barrier reducing gene flow between <i>allex</i> and <i>paulus</i> and +in separating completely the two populations for limited periods.</p> + +<div class="smaller"> +<a name="FNanchor_1_50" id="FNanchor_1_50"></a> +<a name="FNanchor_2_51" id="FNanchor_2_51"></a> +<a name="FNanchor_3_52" id="FNanchor_3_52"></a> +<a name="FNanchor_4_53" id="FNanchor_4_53"></a> +<a name="FNanchor_5_54" id="FNanchor_5_54"></a> +<p><i>Specimens examined.</i>—Total 176, all from the Republic of México and distributed +as follows: <span class="smcap">Chihuahua</span>: Rancho Sanignacio, 4 mi. S, 1 mi. W Santo +Tomás, 1; El Rosario, 6700 ft., 1; 2 mi. W Miñaca, 6900 ft., 11; +Balleza, 1<a href="#Footnote_1_50" class="fnanchor">[50]</a>. +<span class="smcap">Durango</span>: Rosario, 1<a href="#Footnote_2_51" class="fnanchor">[51]</a>; +type locality, 14<a href="#Footnote_2_51" class="fnanchor">[51]</a> (including the type); +<i>San Gabriel</i>, 2<a href="#Footnote_2_51" class="fnanchor">[51]</a>; +<i>Rancho Santuario</i>, 2<a href="#Footnote_2_51" class="fnanchor">[51]</a>; +1 mi. N Chorro, 6450 ft., 1; <i>8 mi. NE Durango</i>, 6200 ft., 2; 5 mi. N Durango, 6400 ft., 2. +<span class="smcap">Zacatecas</span>: Valparaíso, 6500 ft., 10<a href="#Footnote_1_50" class="fnanchor">[50]</a>. +<span class="smcap">Aguascalientes</span>: <i>18 mi. W, 2 mi. S Aguascalientes</i>, 6000 ft., 1; +16 mi. S Aguascalientes, 5<a href="#Footnote_3_52" class="fnanchor">[52]</a>. +<span class="smcap">Jalisco</span>: 1 mi. NE Villa Hidalgo, 6500 ft., 1; +2 mi. WNW Lagos de Moreno, 6370 ft., 19; <i>2 mi. ESE Tequila</i>, 4000 ft., 11; +<i>3 mi. W La Venta</i>, 33, 1<a href="#Footnote_4_53" class="fnanchor">[53]</a>; +<i>12 mi. W Guadalajara</i>, 3<a href="#Footnote_5_54" class="fnanchor">[54]</a>; +<i>Atemajac</i>, 12<a href="#Footnote_1_50" class="fnanchor">[50]</a>; +4 mi. W Guadalajara, 5100 ft., 3; <i>2 mi. N, <sup>1</sup>/<sub>2</sub> mi. W Guadalajara</i>, 11; 2 mi. +NW Magdalena, 4500 ft., 7<a href="#Footnote_1_50" class="fnanchor">[50]</a>; +<i>1 mi. N Tala</i>, 4400 ft., 3; 3 mi. W Tala, 4300 ft., 18.</p> + +<p><i>Marginal records.</i>—<span class="smcap">Chihuahua</span>: Rancho Sanignacio, 4 mi. S, 1 mi. W +Santo Tomás; El Rosario; Balleza. <span class="smcap">Durango</span>: Rosario, 6700 ft.; 1 mi. E Zarca +(Blossom and Burt, 1942:1); 1 mi. N Chorro, 6450 ft. <span class="smcap">Zacatecas</span>: Valparaíso, +6500 ft. <span class="smcap">Aguascalientes</span>: 1 mi. N Chicalote (Blossom and Burt, +1942:4). <span class="smcap">Jalisco</span>: 2 mi. WNW Lagos de Moreno, 6370 ft.; 4 mi. W Guadalajara, +5100 ft.; 3 mi. W Tala, 4300 ft.; 2 mi. NW Magdalena, 4500 ft. +<span class="smcap">Durango</span>: 5 mi. N Durango, 6400 ft.; type locality. <span class="smcap">Chihuahua</span>: 2 mi. W +Miñaca, 6900 ft.</p> +</div> + +<div class="footnote"><p><a name="Footnote_1_50" id="Footnote_1_50"></a> +<a href="#FNanchor_1_50"><span class="label">[50]</span></a> United States National Museum (Biol. Surv. Collections).</p></div> + +<div class="footnote"><p><a name="Footnote_2_51" id="Footnote_2_51"></a> +<a href="#FNanchor_2_51"><span class="label">[51]</span></a> American Museum of Natural History.</p></div> + +<div class="footnote"><p><a name="Footnote_3_52" id="Footnote_3_52"></a> +<a href="#FNanchor_3_52"><span class="label">[52]</span></a> Univ. Illinois, Mus. Nat. History.</p></div> + +<div class="footnote"><p><a name="Footnote_4_53" id="Footnote_4_53"></a> +<a href="#FNanchor_4_53"><span class="label">[53]</span></a> The Museum, Michigan State Univ.</p></div> + +<div class="footnote"><p><a name="Footnote_5_54" id="Footnote_5_54"></a> +<a href="#FNanchor_5_54"><span class="label">[54]</span></a> Univ. Michigan, Museum of Zoology.</p> + +<p><span class="pagenum"><a name="Page_650" id="Page_650">[Pg 650]</a></span></p></div> + + +<div class="caption3"><a name="Baiomys_taylori_subater" id="Baiomys_taylori_subater"></a> +<b>Baiomys taylori subater</b> (V. Bailey)</div> + +<div class="species_ref"><i>Peromyscus taylori subater</i>, V. Bailey, N. Amer. Fauna, 25:102, October 24, +1905; Lyon and Osgood, Bull. U. S. Nat. Mus., 62:139, January 15, +1909; Osgood, N. Amer. Fauna, 28:255, April 17, 1909; Elliot, Check-List +Mamm. N. Amer. Continent, West Indies and Neighboring Seas, +Suppl., Amer. Mus. Nat. Hist, p. 44, January 8, 1917.</div> + +<div class="species_ref"><i>Baiomys taylori subater</i>, Miller, Bull. U. S. Nat. Mus., 79:136, December +31, 1912; Miller, Bull. U. S. Nat. Mus., 128:317, April 29, 1924; Anthony, +Field Book of North American Mammals, p. 348, 1928; Baker, Jour. +Mamm., 21:223, May 14, 1940; Ellerman, The Families and Genera of +Living Rodents, 2:402, March 21, 1941; Blair, Jour. Mamm., 22:378, +November 14, 1941; Poole and Schantz, Bull. U. S. Nat. Mus., 178:259, +March 6, 1942; Blair, Jour. Mamm., 23:196, May 14, 1942; Blair and +Blossom, Contrib. Lab. Vert. Biol., Univ. Michigan, 40:1, March, 1948; +Miller and Kellogg, Bull. U. S. Nat. Mus., 205:511, March 3, 1955; Hall +and Kelson, The Mammals of North America, 2:659, March 31, 1959.</div> + +<div class="species_ref"><i>Baiomys taylori</i> [= <i>subater</i>], Taylor and Davis, Texas Game, Fish and +Oyster Comm. Bull., 27:56, August, 1947 (part).</div> + +<div class="smaller"> +<p><i>Type.</i>—Subadult female, skin and skull; No. 32616/44539 U. S. Nat. Mus. +(Biol. Surv. Coll.); Bernard Creek, near Columbia, Brazoria County, Texas; +obtained on February 25, 1892, by W. Lloyd, original number 1122.</p> + +<p><i>Range.</i>—Southeastern Texas, north of Matagorda Bay west to Lavaca +County, north to Brazos and Walker counties thence east to Jefferson County, +see <a href="#fig11">Figure 11</a>. Occurs from near sea level in Brazoria and Galveston counties, +up to 500 feet in western part of range. Zonal range: Humid division of +lower Austral (the western part of the Austroriparian Biotic Province of Dice, +1943:18-21).</p> + +<p><i>Diagnosis.</i>—Size medium to large for the species; mid-dorsal region Clove +Brown (sooty in freshly captured specimens); some parts of mid-dorsal region +all blackish; individual guard hairs of dorsum black-tipped, Deep Neutral +Gray basally; underfur black-tipped with subterminal band of light buff, +Neutral Gray at base; belly grayish-white, laterally Isabella Color; distal three-fourths +of hairs in region of throat and chin white, proximal fourth light gray; +in median region of belly distal half of individual hairs white, proximal half +dark gray; vibrissae in most specimens black to base. Average and extreme +cranial measurements of six adults from 7 mi. S La Belle are as follows: +occipitonasal length, 18.9 (17.5-19.4); zygomatic breadth, 9.6 (9.1-9.9); postpalatal +length, 6.8 (6.2-7.2); least interorbital breadth, 3.7 (3.4-3.9); length +of incisive foramina, 4.0 (3.6-4.2); length of rostrum, 6.5 (6.1-6.8); breadth +of braincase, 8.7 (8.3-8.9); depth of cranium, 6.7 (6.6-6.8); alveolar length +of maxillary tooth-row, 3.1 (2.9-3.2). Average and extreme external measurements +of four adults from Richmond are as follows: total length, 111.5 +(108-118); length of tail vertebrae, 43.5 (41-47); length of body, 68 (67-71); +length of hind foot, 14 (13-15); for photographs of the skull, +see <a href="#plate2">Plate 2<i>f</i></a>, and <a href="#plate4">Plate 4<i>g</i></a>.</p> + +<p><i>Comparisons.</i>—Because <i>B. t. subater</i> intergrades only with <i>B. t. taylori</i> to +the south and west, <i>subater</i> is compared only with <i>taylori</i>. Young adults of +both subspecies in unworn pelage show best the colors that differentiate the +two subspecies. Old adults of <i>subater</i> in worn pelage appear grayish, resembling +<i>taylori</i>, and at that age, only certain cranial characters are of +taxonomic use. Cranially, <i>subater</i> differs from <i>taylori</i> in: presphenoid not +shaped like an hour-glass; parapterygoid processes thicker medially; interparietal +diamond-shaped instead of elongated and compressed. Skull slightly larger +in most measurements.</p> +</div> +<br /> +<br /> + +<div class="caption1">PLATE 1</div> +<br /> +<div class="fig_center" style="width: 444px;"> +<a name="plate1" id="plate1"></a> +<img src="images/plate_1.png" width="444" height="692" alt="" /> +</div> +<br /> +Photographs of skulls in dorsal view of <i>Baiomys</i>. × 2.<br /> +<br /> +<table summary="list"> +<tr><td class="text_lf"><i>a.</i> <i>B. m. brunneus</i>, ♀ ad., 10834, AMNH, Jalapa, Veracruz.<br /> +<i>b.</i> <i>B. m. grisescens</i>, ♀ ad., 257080, USNM, Comayabuela, Honduras.<br /> +<i>c.</i> <i>B. m. handleyi</i>, ♀ ad., 275597, USNM, Sacapulas, Guatemala.<br /> +<i>d.</i> <i>B. m. infernatis</i>, ♀ ad., 91499, MZUM, Teotitlán, Oaxaca.<br /> +<i>e.</i> <i>B. m. musculus</i>, ♀ ad., 45462, USNM, Colima, Colima.<br /> +<i>f.</i> <i>B. m. nigrescens</i>, ♂ ad., 76834, USNM, Comitán, Chiapas.<br /> +<i>g.</i> <i>B. m. pallidus</i>, ♀ ad., 4802, Texas A & M, Axochiapán, Morelos.<br /> +<i>h.</i> <i>B. m. pullus</i>, ♀ ad., 71608, KU, 8 mi. S Condega, Nicaragua.<br /> +<i>i.</i> <i>B. t. allex</i>, ♀ ad., 45453, USNM, Colima, Colima.<br /> +</td> +</tr> +</table> +<br /> +<br /> + +<div class="caption1">PLATE 2</div> +<br /> +<div class="fig_center" style="width: 437px;"> +<a name="plate2" id="plate2"></a> +<img src="images/plate_2.png" width="437" height="670" alt="" /> +</div> +<br /> +Photographs of skulls (<i>a-g</i>) in dorsal view of <i>Baiomys</i>. × 2.<br /> +<br /> +<table summary="list"> +<tr><td class="text_lf"><i>a.</i> <i>B. t. analogous</i>, ♀ ad., 120265, USNM, Zamora, Michoacán.<br /> +<i>b.</i> <i>B. t. ater</i>, ♀ ad., 15056, UI, 1<sup>1</sup>/<sub>2</sub> mi. ENE Greaterville, Arizona.<br /> +<i>c.</i> <i>B. t. canutus</i>, ♀ ad., 62076, KU, 1 mi. S Pericos, Sinaloa.<br /> +<i>d.</i> <i>B. t. fuliginatus</i>, ♀ ad., 36771, KU, type locality.<br /> +<i>e.</i> <i>B. t. paulus</i>, ♀ ad., 40032, KU, 18 mi. W, 2 mi. S Aguascalientes.<br /> +<i>f.</i> <i>B. t. subater</i>, ♀ ad., 44543, USNM, type locality.<br /> +<i>g.</i> <i>B. t. taylori</i>, ♀ ad., 57944, KU, 5 mi. E San Antonio, Texas.<br /> +<i>h.</i> Photo. of captive ♂ <i>B. t. taylori</i>, 25 mi. E Austin, Texas. × 1.<br /> +</td> +</tr> +</table> +<br /> +<br /> + +<div class="caption1">PLATE 3</div> +<br /> +<div class="fig_center" style="width: 433px;"> +<a name="plate3" id="plate3"></a> +<img src="images/plate_3.png" width="433" height="673" alt="" /> +</div> +<br /> +Photographs of skulls in ventral view of <i>Baiomys</i>. × 2.<br /> +<br /> +<table summary="list"> +<tr><td class="text_lf"><i>a.</i> <i>B. m. brunneus</i>, ♀ ad., 10834, AMNH, Jalapa, Veracruz.<br /> +<i>b.</i> <i>B. m. grisescens</i>, ♀ ad., 257080, USNM, Comayabuela, Honduras.<br /> +<i>c.</i> <i>B. m. handleyi</i>, ♀ ad., 275597, USNM, Sacapulas, Guatemala.<br /> +<i>d.</i> <i>B. m. infernatis</i>, ♀ ad., 91499, MZUM, Teotitlán, Oaxaca.<br /> +<i>e.</i> <i>B. m. musculus</i>, ♀ ad., 45462, USNM, Colima, Colima.<br /> +<i>f.</i> <i>B. m. nigrescens</i>, ♂ ad., 76834, USNM, Comitán, Chiapas.<br /> +<i>g.</i> <i>B. m. pallidus</i>, ♀ ad., 4802, Texas A & M, Axochiapán, Morelos.<br /> +<i>h.</i> <i>B. m. pullus</i>, ♀ ad., 71608, KU, 8 mi. S Condega, Nicaragua.<br /> +</td> +</tr> +</table> +<br /> +<br /> + +<div class="caption1">PLATE 4</div> +<br /> +<div class="fig_center" style="width: 450px;"> +<a name="plate4" id="plate4"></a> +<img src="images/plate_4.png" width="450" height="687" alt="" /> +</div> +<br /> +Photographs of skulls in ventral view of <i>Baiomys</i>. × 2.<br /> +<br /> +<table summary="list"> +<tr><td class="text_lf"> +<i>a.</i> <i>B. t. allex</i>, ♀ ad., 45453, USNM, Colima, Colima.<br /> +<i>b.</i> <i>B. t. analogous</i>, ♀ ad., 120265, USNM, Zamora, Michoacán.<br /> +<i>c.</i> <i>B. t. ater</i>, ♀ ad., 15056, UI, 1 mi. ENE Greaterville, Arizona.<br /> +<i>d.</i> <i>B. t. canutus</i>, ♀ ad., 62076, KU, 1 mi. S Pericos, Sinaloa<br /> +<i>e.</i> <i>B. t. fuliginatus</i>, ♀ ad., 36771, KU, type locality.<br /> +<i>f.</i> <i>B. t. paulus</i>, ♀ ad., 40032, KU, 18 mi. W, 2 mi. S Aguascalientes.<br /> +<i>g.</i> <i>B. t. subater</i>, ♀ ad., 44543, USNM, type locality.<br /> +<i>h.</i> <i>B. t. taylori</i>, ♀ ad., 57944, KU, 5 mi. E San Antonio, Texas.<br /> +</td> +</tr> +</table> +<br /> +<br /> + +<p><span class="pagenum"><a name="Page_651" id="Page_651">[Pg 651]</a></span></p> + +<p><i>Remarks.</i>—This subspecies retains its chief diagnostic character, +blackish mid-dorsal region, throughout nearly all parts of its range. +Specimens from the general area of Matagorda Bay and Lavaca +County grade into <i>taylori</i> in characters of color and crania. The +Colorado and Brazos rivers seemingly serve as barriers reducing +gene flow between <i>taylori</i> and <i>subater</i>. These rivers may well have +been important factors in the origin and the limitation of these two +seemingly closely-related subspecies.</p> + +<p><i>Baiomys taylori subater</i> is not differentiated in color of pelage +and characters of crania from <i>B. t. taylori</i> to the same degree that +<i>B. t. paulus</i> is differentiated from <i>B. t. analogous</i>, or that <i>B. t. taylori</i> +is differentiated from several of the other subspecies of <i>Baiomys +taylori</i>. <i>B. t. subater</i> probably is a more recent occupant of the +area in which it now lives than is the case with any other one of +the subspecies of <i>taylori</i>. Sufficient time probably has not elapsed +to allow for formation of more distinctive phenotypic patterns.</p> + +<div class="smaller"> +<a name="FNanchor_1_55" id="FNanchor_1_55"></a> +<a name="FNanchor_2_56" id="FNanchor_2_56"></a> +<a name="FNanchor_3_57" id="FNanchor_3_57"></a> +<a name="FNanchor_4_58" id="FNanchor_4_58"></a> +<a name="FNanchor_5_59" id="FNanchor_5_59"></a> +<p><i>Specimens examined.</i>—Total 65, all from <span class="smcap">Texas</span> +and distributed as follows: <i>Brazos County</i>: <sup>1</sup>/<sub>2</sub> mi. NW College Station, +1<a href="#Footnote_1_55" class="fnanchor">[55]</a>; <i>3 mi. W College Station</i>, +<i>1 mi. W Easterwood Airport</i>, 1<a href="#Footnote_1_55" class="fnanchor">[55]</a>; +<i>College Station</i>, 1<a href="#Footnote_1_55" class="fnanchor">[55]</a>. +<i>Walker County</i>: Huntsville, 1<a href="#Footnote_1_55" class="fnanchor">[55]</a>. +<i>Hardin County</i>: Sour Lake, 1<a href="#Footnote_3_57" class="fnanchor">[57]</a>. +<i>Jefferson County</i>: 7 mi. S Labelle, 10. <i>Harris County</i>: 6 mi. NE Crosby, +1<a href="#Footnote_2_56" class="fnanchor">[56]</a>. <i>Colorado County</i>: <i>10 mi. N Eagle Lake</i>, +1<a href="#Footnote_1_55" class="fnanchor">[55]</a>; <i>9 mi. N Eagle Lake</i>, +1<a href="#Footnote_1_55" class="fnanchor">[55]</a>; 2 mi. W Eagle Lake, 1; +<i>Eagle Lake</i>, 1<a href="#Footnote_1_55" class="fnanchor">[55]</a>, 5. +<i>Fort Bend County</i>: Richmond, 4<a href="#Footnote_3_57" class="fnanchor">[57]</a>. +<i>Galveston County</i>: <i>Texas City</i>, 6<a href="#Footnote_4_58" class="fnanchor">[58]</a>; +Virginia Point, 1<a href="#Footnote_3_57" class="fnanchor">[57]</a>. +<i>Brazoria County</i>: <i>Austin Bayou near Alvin</i>, 2<a href="#Footnote_3_57" class="fnanchor">[57]</a>; +14 mi. SSE Alvin, 2<a href="#Footnote_5_59" class="fnanchor">[59]</a>; +type locality, 7<a href="#Footnote_3_57" class="fnanchor">[57]</a> (including the type). +<i>Lavaca County</i>: 4 mi. W Hallettsville, 1<a href="#Footnote_1_55" class="fnanchor">[55]</a>; +<i>1 mi. SW Hallettsville</i>, 3<a href="#Footnote_1_55" class="fnanchor">[55]</a>; +<i>13.7 mi. SW Hallettsville</i>, 2<a href="#Footnote_1_55" class="fnanchor">[55]</a>; +4 mi. NE Yoakum, 11.</p> + +<p><i>Marginal records.</i>—<span class="smcap">Texas</span>: Huntsville; Sour Lake; 7 mi. S La Belle; +Virginia Point; 14 mi. SSE Alvin; type locality; 4 mi. NE Yoakum; 4 mi. W +Hallettsville; <sup>1</sup>/<sub>2</sub> mi. NW College Station.</p> +</div> + +<div class="footnote"><p><a name="Footnote_1_55" id="Footnote_1_55"></a> +<a href="#FNanchor_1_55"><span class="label">[55]</span></a> Texas A & M, Cooperative Wildlife Research Collection.</p></div> + +<div class="footnote"><p><a name="Footnote_2_56" id="Footnote_2_56"></a> +<a href="#FNanchor_2_56"><span class="label">[56]</span></a> Carnegie Museum.</p></div> + +<div class="footnote"><p><a name="Footnote_3_57" id="Footnote_3_57"></a> +<a href="#FNanchor_3_57"><span class="label">[57]</span></a> U. S. Nat. Museum (Biol. Surv. Coll.).</p></div> + +<div class="footnote"><p><a name="Footnote_4_58" id="Footnote_4_58"></a> +<a href="#FNanchor_4_58"><span class="label">[58]</span></a> Los Angeles County Museum.</p></div> + +<div class="footnote"><p><a name="Footnote_5_59" id="Footnote_5_59"></a> +<a href="#FNanchor_5_59"><span class="label">[59]</span></a> American Museum of Natural History.</p></div> + + +<div class="caption3"><a name="Baiomys_taylori_taylori" id="Baiomys_taylori_taylori"></a> +<b>Baiomys taylori taylori</b> (Thomas)</div> + +<div class="species_ref"><i>Hesperomys</i> (<i>Vesperimus</i>) <i>taylori</i> Thomas, Ann. Mag. Nat. Hist., ser. 5, +19:66, January, 1887.</div> + +<div class="species_ref"><i>Baiomys taylori</i> [<i>taylori</i>], Mearns, Bull. U. S. Nat. Mus., 56:381, April 13, +1907; Stickel and Stickel, Jour. Mamm., 30:141, May 23, 1949.</div> + +<div class="species_ref">Baiomys taylori taylori, Miller, Bull. U. S. Nat. Mus., 79:136, December 31, +1912; Miller, Bull. U. S. Nat. Mus., 128:317, April 29, 1924; Anthony, +Field Book of North American Mammals, p. 327, 1928; Ellerman, The +Families and Genera of Living Rodents, 2:402, March 21, 1941; Taylor +and Davis, Texas Game, Fish and Oyster Comm. Bull., 27:56, August, +1947 (part); Blair, Texas Jour. Sci., 2:104, March 31, 1950; Goldman, +<span class="pagenum2"><a name="Page_652" id="Page_652">[Pg 652]</a></span> +Smith. Miscl. Coll., 115:373, 426, July 31, 1951; Baker, Univ. Kansas +Publs., Mus. Nat. Hist., 5:212, December 15, 1951; Blair, Texas Jour. +Sci., 4:242, June 30, 1952; Hooper, Occas. Papers, Univ. Michigan, Mus. +Zool., 544:7, March 25, 1953; Dalquest, Louisiana State Univ. Studies +(Biol. Sci. Ser.), 1:155, December 28, 1953 (part); Blair, Adv. in +Genetics, 5:10, January 27, 1954; Miller and Kellogg, Bull. U. S. Nat. +Mus., 205:511, March 3, 1955; Baker, Univ. Kansas Publs., Mus. Nat. +Hist., 9:273, June 15, 1956; Packard, Proc. Biol. Soc. Washington, 71:17, +April 11, 1958; Hall and Kelson, The Mammals of North America, 2:659, +March 31, 1959 (part).</div> + +<div class="species_ref"><i>Cricetus</i> (<i>Vesperimus</i>) <i>taylori</i>, Thomas, Proc. Zool. Soc. London, 68:446, +November 20, 1888.</div> + +<div class="species_ref"><i>Sitomys taylori</i>, Merriam, Proc. Biol. Soc. Washington, 7:170, September +29, 1892.</div> + +<div class="species_ref"><i>Sitomys</i> (<i>Baiomys</i>) <i>taylori</i>, True, Proc. U. S. Nat. Mus., 16(972):758, +February 7, 1894; J. A. Allen, Bull. Amer. Mus. Nat. Hist., 6:181, May +31, 1894.</div> + +<div class="species_ref"><i>S.</i> [<i>itomys</i>] <i>taylori</i>, Rhoads, Proc. Acad. Nat. Sci. Philadelphia, 46:256, +October, 1894.</div> + +<div class="species_ref"><i>Peromyscus</i> (<i>Baiomys</i>) <i>taylori</i>, J. A. Allen, Bull. Amer. Mus. Nat. Hist., +8:65, April 22, 1896.</div> + +<div class="species_ref">[<i>Peromyscus</i>] <i>taylori</i>, Trouessart, Cat. Mamm., 1:517, 1898.</div> + +<div class="species_ref"><i>Peromyscus taylori</i> [<i>taylori</i>], Elliot, Field Columb. Mus. Publ., 105(4):135, +July 1, 1905; V. Bailey, N. Amer. Fauna, 25:101, October 24, 1905; Elliot, +Field Columb. Mus. Publ., 115(8):203, 1907; Osgood, N. Amer. Fauna, +28:253, April 17, 1909.</div> + +<div class="smaller"> +<p><i>Type.</i>—Adult male, skin and skull; No. 87.11.24.1, British Museum, Natural +History; San Diego, Duval County, Texas; obtained by William Taylor.</p> + +<p><i>Range.</i>—North-central to southeastern Texas, excluding the coastal plain +north of the region of Matagorda Bay, thence south into the southern part of +Tamaulipas and west into Coahuila and Nuevo León, see <a href="#fig11">Figure 11</a>. Occurs +from near sea level in Texas up to 1500 feet in Coahuila. Zonal range: mostly +Lower Austral (in México and southeastern half of Texas, the Tamaulipas +Biotic Province of Goldman and Moore, 1945:349, and Blair, 1952:230).</p> + +<p><i>Diagnosis.</i>—Size medium for the species; dorsum grayish in freshly taken +specimens to Hair Brown in preserved specimens; individual guard hairs of +dorsum black-tipped, grayish basally, underfur black-tipped with a subterminal +band of olive-buff; sides of body pale-grayish near venter, individual hairs +buffy proximally, grayish basally; belly pale grayish, individual hairs white-tipped, +Pale Neutral Gray basally; throat and chin colored as is belly; forefeet +and hind feet sooty-gray dorsally, sparsely-haired ventrally, thus appearing +flesh-colored; tail unicolored gray to sooty-gray. Average and extreme cranial +measurements of 22 adults from 6 mi. SW San Gerónimo, Coahuila, are as +follows: occipitonasal length, 18.0 (17.4-19.0); zygomatic breadth, 9.6 +(9.2-10.2); postpalatal length, 6.5 (5.9-7.1); least interorbital breadth, 3.6 +(3.3-3.8); length of incisive foramina, 4.0 (3.6-4.3); length of rostrum, 6.1 +(5.7-6.7); breadth of brain case, 8.8 (8.5-9.1); depth of cranium, 6.5 (6.0-7.0); +alveolar length of maxillary tooth-row, 3.1 (3.0-3.3). Average and extreme +external measurements of 19 adults from 6 mi. SW San Gerónimo are as follows: +total length, 102.2 (95-115); length of tail vertebrae, 39.4 (21-46); +length of body, 62.8 (53-76); length of hind foot, 14.0 (12-15); length of +ear from notch, 10.7 (10-12); for photographs of skull, +see <a href="#plate2">Plate 2<i>g</i></a>, and <a href="#plate4">Plate 4<i>h</i></a>.</p> + +<p><span class="pagenum2"><a name="Page_653" id="Page_653">[Pg 653]</a></span></p> + +<p><i>Comparisons.</i>—For comparisons with <i>B. t. subater</i>, <i>B. t. analogous</i>, and <i>B. t. +fuliginatus</i>, see accounts of those subspecies. From <i>B. t. paulus</i>, found to the +southwest, <i>B. t. taylori</i> differs as follows: dorsum grayish rather than fawn-colored; +hairs on dorsal parts of forefeet and hind feet sooty-gray (not white +to white-brown); venter gray to Light Drab-Gray, rather than whitish with +gray overtones; tail unicolored instead of bicolored; skull averaging slightly +larger over-all; maxillary part of zygoma forms right angle with rostrum +rather than obtuse angle; incisive foramina extending posteriorly to anterior +plane of first upper molars instead of to a transverse plane at middle of right +and left first upper molars; bullae less inflated; interorbital region broader +relative to length of skull; rostrum sloping gently from frontonasal suture to +anterior tip of nasals rather than declining abruptly from frontonasal suture +to anterior tip of nasals.</p> +</div> + +<p><i>Remarks.</i>—The geographic range of <i>taylori</i> is relatively large, +and the subspecies is locally variable. Nevertheless, none of the +external and cranial measurements of specimens assigned to this +subspecies differs significantly from the corresponding measurements +of material from the type locality and adjacent areas in +southeastern Texas. In southeastern Texas, south of the Guadalupe +River, south to the coastal plain of Tamaulipas, this subspecies +differs in color (being paler) from <i>B. t. subater</i> with which <i>taylori</i> +might be confused. The foothills of the Sierra Madre Oriental in +western Tamaulipas, north through Nuevo León and Coahuila, +seem to mark the southwestern limit of the range assignable to +<i>taylori</i>.</p> + +<p>On December 27, 1958, a specimen, KU 81552, was obtained 3 mi. +N Bowie, Montague County, Texas. This record station extends +the known range of <i>B. taylori</i> 65 miles northward from the previous +northernmost locality, listed by Hunsaker, Raun, and Swindells +(1959:447). Two specimens, KU 81553 and 81554, were collected +by the author 2 mi. NE Cedar Hill, Dallas County, Texas, on October +31, 1958. These two specimens, plus the single specimen from +Bowie County are all paler with more buffy bellies than either +<i>B. t. taylori</i> or <i>B. t. subater</i>. They may represent an incipient subspecies. +I tentatively assign them to <i>B. t. taylori</i> because of the +pale rather than dark (like <i>B. t. subater</i>) pelage. Additional specimens +are needed from these areas and from the hiatus between the +ranges of <i>B. t. taylori</i> and <i>B. t. subater</i> the better to understand +the manner in which these two subspecies intergrade.</p> + +<p>Among named subspecies of <i>Baiomys taylori</i>, <i>B. t. taylori</i> most +closely resembles <i>B. t. subater</i> to the north in Texas. Nine specimens +examined from Yoakum are intergrades between <i>taylori</i> and <i>subater</i>. +These specimens have the sooty dorsal color of <i>subater</i>, but ventrally +are inseparable from topotypes of <i>taylori</i>. In length of body and +<span class="pagenum"><a name="Page_654" id="Page_654">[Pg 654]</a></span> +tail, specimens from Yoakum are like <i>subater</i>, but in length of hind +foot, they are intermediate between the two subspecies. Cranially, +they are like <i>subater</i>. When all characters are considered, the specimens +are best referred to <i>subater</i>. Bailey (1905:103) suggested +that specimens from the southern part of the range, which he ascribed +to <i>subater</i>, tended to a more grayish color than topotypes of +<i>subater</i>, therefore, grading into <i>taylori</i>. The zone of intergradation +runs from Matagorda Bay northwest through Lavaca County, thence +north to the Colorado River, and closely follows the boundary between +the Lower Austral and Humid Division of Lower Austral +Life-zone as plotted by Bailey (<i>loc. cit.</i>). Findley (1955:44) pointed +out that where two life-zones meet, the resulting populations of +shrews are mostly intergrades. Such is the case between these two +subspecies of <i>Baiomys taylori</i> in an area where life-zones might seem +less important than in the mountainous west.</p> + +<p>In the southern part of the range of <i>taylori</i>, intergradation occurs +between <i>B. t. taylori</i> in western Tamaulipas and <i>B. t. fuliginatus</i> in +the mountains of San Luis Potosí.</p> + +<p>Dalquest (1953:156) found no indication of intergradation between +the two species, <i>B. taylori</i> and <i>B. musculus</i>, in San Luis Potosí. +After examination of specimens from San Luis Potosí, I am in agreement +that they are all referable to the species <i>taylori</i>.</p> + +<div class="smaller"> +<a name="FNanchor_1_60" id="FNanchor_1_60"></a> +<a name="FNanchor_2_61" id="FNanchor_2_61"></a> +<a name="FNanchor_3_62" id="FNanchor_3_62"></a> +<a name="FNanchor_4_63" id="FNanchor_4_63"></a> +<a name="FNanchor_5_64" id="FNanchor_5_64"></a> +<a name="FNanchor_6_65" id="FNanchor_6_65"></a> +<a name="FNanchor_7_66" id="FNanchor_7_66"></a> +<a name="FNanchor_8_67" id="FNanchor_8_67"></a> +<a name="FNanchor_9_68" id="FNanchor_9_68"></a> +<p><i>Specimens examined.</i>—Total 435. <span class="smcap">Texas</span>: +<i>Montague County</i>: 3 mi. N Bowie, 1. <i>Dallas County</i>: 2 mi. NE Cedar Hill, 2. +<i>Travis County</i>: 8 mi. NW Austin, 2<a href="#Footnote_1_60" class="fnanchor">[60]</a>; +<i>Austin</i>, 2<a href="#Footnote_1_60" class="fnanchor">[60]</a>; +<i>4 mi. E Austin</i>, 4<a href="#Footnote_1_60" class="fnanchor">[60]</a>; +<i>5 mi. E Austin</i>, 3<a href="#Footnote_1_60" class="fnanchor">[60]</a>; +<i>6 mi. E Austin</i>, 16<a href="#Footnote_1_60" class="fnanchor">[60]</a>, 1; +<i>7 mi. E Austin</i>, 1<a href="#Footnote_1_60" class="fnanchor">[60]</a>; +<i>15 mi. E Austin</i>, 1<a href="#Footnote_1_60" class="fnanchor">[60]</a>; +<i>4 mi. S Austin</i>, 1<a href="#Footnote_1_60" class="fnanchor">[60]</a>. +<i>Bastrop County</i>: 25 mi. E Austin, 2. <i>Kendall County</i>: +Boerne, 1<a href="#Footnote_2_61" class="fnanchor">[61]</a>. +<i>Bexar County</i>: <i>1 mi. N Randolph Field</i>, 3<a href="#Footnote_5_64" class="fnanchor">[64]</a>; +<i>5 mi. ENE</i> (<i>on U. S. Highway 81</i>) <i>San Antonio</i>, 1; +<i>3 mi. NE San Antonio</i>, 1; San Antonio, 26<a href="#Footnote_2_61" class="fnanchor">[61]</a>, +11<a href="#Footnote_3_62" class="fnanchor">[62]</a>, 1<a href="#Footnote_4_63" class="fnanchor">[63]</a>; +<i>5 mi. E San Antonio</i>, 11; <i>4<sup>1</sup>/<sub>2</sub> mi. E Sayers</i>, 3. +<i>Gonzales County</i>: 7 mi. S Luling, 2<a href="#Footnote_1_60" class="fnanchor">[60]</a>. +<i>Wilson County: 4 mi. W LaVernia</i>, 3; 12 mi. W Floresville, 1. +<i>Atascosa County</i>: 9 mi. SW Somerset, 1. <i>Goliad County</i>: 8 mi. NE Goliad, +1<a href="#Footnote_1_60" class="fnanchor">[60]</a>. +<i>Bee County</i>: Beeville, 1<a href="#Footnote_2_61" class="fnanchor">[61]</a>. +<i>Aransas County</i>: Aransas (Wildlife) Refuge, 1<a href="#Footnote_6_65" class="fnanchor">[65]</a>; +<i>5 mi. E Copana Bay</i>, 1<a href="#Footnote_6_65" class="fnanchor">[65]</a>; +<i>4.6 mi. NE Rockport</i>, 5<a href="#Footnote_1_60" class="fnanchor">[60]</a>; +<i>4.5 mi. NW Rockport</i>, 2<a href="#Footnote_1_60" class="fnanchor">[60]</a>; +3 mi. N, 2 mi. E Rockport, 4; <i>Rockport</i>, 1<a href="#Footnote_1_60" class="fnanchor">[60]</a>, +1<a href="#Footnote_2_61" class="fnanchor">[61]</a>, 1<a href="#Footnote_4_63" class="fnanchor">[63]</a>; +<i>1<sup>1</sup>/<sub>2</sub> mi. SW Rockport</i>, 1<a href="#Footnote_1_60" class="fnanchor">[60]</a>; +<i>2 mi. SW Rockport</i>, 2<a href="#Footnote_1_60" class="fnanchor">[60]</a>; +<i>13.4 mi. SW Rockport</i>, 1<a href="#Footnote_1_60" class="fnanchor">[60]</a>; +<i>14 mi. SW Rockport</i>, 1. <i>San Patricio County</i>: Welder Wildlife Refuge, 7. +<i>Duval County</i>: type locality, 2<a href="#Footnote_2_61" class="fnanchor">[61]</a>, +1<a href="#Footnote_7_66" class="fnanchor">[66]</a>. +<i>Nueces County</i>: Corpus Christi (south Nueces Bay), 1<a href="#Footnote_5_64" class="fnanchor">[64]</a> +(Cleveland Mus. Coll.). <i>Kleberg County:</i> 2 mi. S Riviera, +3<a href="#Footnote_6_65" class="fnanchor">[65]</a>. <i>Brooks County</i>: 3 mi. S Falfurrias, +2<a href="#Footnote_6_65" class="fnanchor">[65]</a>. <i>Hidalgo County</i>: +6 mi. S McAllen, 17<a href="#Footnote_1_60" class="fnanchor">[60]</a>. +<i>Willacy County</i>: 28 mi. E Raymondville, 10<a href="#Footnote_6_65" class="fnanchor">[65]</a>. +<i>Cameron County</i>: Brownsville, 31<a href="#Footnote_2_61" class="fnanchor">[61]</a>, +23<a href="#Footnote_3_62" class="fnanchor">[62]</a>, 5<a href="#Footnote_5_64" class="fnanchor">[64]</a>. +<span class="smcap">Coahuila</span>: 6 mi. SW San Gerónimo, 32. +<span class="smcap">Nuevo León</span>: Santa Catarina, 1<a href="#Footnote_2_61" class="fnanchor">[61]</a>; +14 mi. N Monterrey, 1950 ft., 2<a href="#Footnote_8_67" class="fnanchor">[67]</a>; +Monterrey, 1<a href="#Footnote_2_61" class="fnanchor">[61]</a>; +20 km. N General Terán, 3<a href="#Footnote_5_64" class="fnanchor">[64]</a>. +<span class="smcap">Tamaulipas</span>: <i>Near Headwaters Río Sabinas, 8 km. W, 10 km. N El Encino</i>, +400 ft., 1; Camargo, 5<a href="#Footnote_2_61" class="fnanchor">[61]</a>; +Charco Escondido, 20 mi. S Reynosa, 3<a href="#Footnote_8_67" class="fnanchor">[67]</a>; +Matomoras, 5<a href="#Footnote_2_61" class="fnanchor">[61]</a>; <i>Ejido Santa Isabel, +2 km. W Inter-American Highway</i>, 2000 ft., 7; Hidaglo, 7<a href="#Footnote_2_61" class="fnanchor">[61]</a>; +<i>Hda. Station Engracia</i>, 4<a href="#Footnote_4_63" class="fnanchor">[63]</a>; +4 mi. N La Pesca, 1; 29 mi. N Ciudad Victoria, 1<a href="#Footnote_8_67" class="fnanchor">[67]</a>; +Ciudad Victoria, 6<a href="#Footnote_2_61" class="fnanchor">[61]</a>, 3; +Jaumavé, 2400 ft., 6<a href="#Footnote_5_64" class="fnanchor">[64]</a>, 10; +Sierra de Tamaulipas, 3<a href="#Footnote_5_64" class="fnanchor">[64]</a>; <i>25 mi. N El Manté, +3 km. W Inter-American Highway</i> (<i>on Rancho Pano Ayuctle</i>), 300 ft., 4; +<i>6 mi. N Gomez Farias</i> (<i>on Rancho Pano Ayuctle</i>), 1; <i>5 mi. NE Gomez Farias</i>, +12<a href="#Footnote_5_64" class="fnanchor">[64]</a>, +1<a href="#Footnote_3_62" class="fnanchor">[62]</a>; 70 km. (by highway) +<span class="pagenum"><a name="Page_655" id="Page_655">[Pg 655]</a></span> +S Ciudad Victoria, 2 km. W El Carrizo, 5<a href="#Footnote_3_62" class="fnanchor">[62]</a>, 2; +Antigua Morelos, 5<a href="#Footnote_5_64" class="fnanchor">[64]</a>; <i>6 mi. N, 6 mi. W Altamira</i>, 31; +<i>5 mi. N, 5 mi. W Altamira</i>, 4; <i>Alta Mira</i> (<i>Altamira</i>), +2<a href="#Footnote_2_61" class="fnanchor">[61]</a>; 1 mi. S Altamira, 6; <i>10 mi. NW Tampico</i>, 1. +<span class="smcap">San Luis Potosí</span>: Ebano, 5<a href="#Footnote_9_68" class="fnanchor">[68]</a>; +<i>4 km. NE Ciudad Valles</i>, 1; Ciudad Valles, 1; <i>3 km. W Tamuín</i>, +1<a href="#Footnote_9_68" class="fnanchor">[68]</a>; <i>Tamuín</i>, +6<a href="#Footnote_9_68" class="fnanchor">[68]</a>; +<i>Pujal</i>, 300 m., 1<a href="#Footnote_5_64" class="fnanchor">[64]</a>. +<span class="smcap">Veracruz</span>: Tampico Alto, 50 ft., 1; Potrero Llano, 350 ft., 1; +Ozulama, 2; Cerro Azul, 350 ft., 1.</p> + +<p><i>Marginal Records.</i>—<span class="smcap">Texas</span>: 3 mi. N Bowie; 2 mi. NE Cedar Hill; +25 mi. E Austin; 7 mi. S Luling; 8 mi. NE Goliad; Aransas (Wildlife) Refuge; +3 mi. N, 2 mi. E Rockport; Corpus Christi (South Nueces Bay); 2 mi. S Riviera; +28 mi. E Raymondville; Brownsville. <span class="smcap">Tamaulipas</span>: Matomores; +4 mi. N La Pesca; 1 mi. S Altamira. <span class="smcap">Veracruz</span>: Tampico Alto; Ozulama; +Cerro Azul; Potrero Llano. <span class="smcap">San Luis Potosí</span>: Ciudad Valles. +<span class="smcap">Tamaulipas</span>: Antigua Morelos; 70 km. S Ciudad Victoria, 2 km. W El Carrizo; +Jaumavé; Hidalgo. <span class="smcap">Nuevo León</span>: 20 km. N General Terán; Santa Catarina. +<span class="smcap">Coahuila</span>: 6 mi. SW San Gerónimo. +<span class="smcap">Texas</span>: 9 mi. SW Somerset; Boerne; 8 mi. NW Austin.</p> +</div> + +<div class="footnote"><p><a name="Footnote_1_60" id="Footnote_1_60"></a> +<a href="#FNanchor_1_60"><span class="label">[60]</span></a> Coll. University of Texas.</p></div> + +<div class="footnote"><p><a name="Footnote_2_61" id="Footnote_2_61"></a> +<a href="#FNanchor_2_61"><span class="label">[61]</span></a> U. S. Nat. Museum (Biol. Surv. Coll.).</p></div> + +<div class="footnote"><p><a name="Footnote_3_62" id="Footnote_3_62"></a> +<a href="#FNanchor_3_62"><span class="label">[62]</span></a> American Museum of Natural History.</p></div> + +<div class="footnote"><p><a name="Footnote_4_63" id="Footnote_4_63"></a> +<a href="#FNanchor_4_63"><span class="label">[63]</span></a> Chicago Natural History Museum.</p></div> + +<div class="footnote"><p><a name="Footnote_5_64" id="Footnote_5_64"></a> +<a href="#FNanchor_5_64"><span class="label">[64]</span></a> Univ. Michigan, Museum of Zoology.</p></div> + +<div class="footnote"><p><a name="Footnote_6_65" id="Footnote_6_65"></a> +<a href="#FNanchor_6_65"><span class="label">[65]</span></a> Texas A & M Coop. Wildlife Res. Coll</p></div>. + +<div class="footnote"><p><a name="Footnote_7_66" id="Footnote_7_66"></a> +<a href="#FNanchor_7_66"><span class="label">[66]</span></a> Carnegie Museum.</p></div> + +<div class="footnote"><p><a name="Footnote_8_67" id="Footnote_8_67"></a> +<a href="#FNanchor_8_67"><span class="label">[67]</span></a> Univ. California, Mus. Vert. Zool.</p></div> + +<div class="footnote"><p><a name="Footnote_9_68" id="Footnote_9_68"></a> +<a href="#FNanchor_9_68"><span class="label">[68]</span></a> Museum of Natural History, Louisiana State University.</p></div> + + +<div class="caption2"><a name="EVOLUTION_AND_SPECIATION" id="EVOLUTION_AND_SPECIATION"></a> +EVOLUTION AND SPECIATION</div> + +<p>The history of the genus dates back to the early late Pliocene, +but morphological change since then has been slight insofar as can +be judged from lower jaws. <i>Baiomys</i> seems to have been relatively +conservative also in types of habitat occupied.</p> + +<p>According to Wilson (1937:59), the late Pliocene was a time of +decided expansion of myomorph rodents, more particularly cricetines. +Furthermore, at this time, the climate in the interior basin +of southwestern North America presumably was becoming arid, if +we can judge from the spread of elements of the Madro-Tertiary +flora. Axelrod (1950:266) points out that the drier, continental +climate initiated in the early Tertiary probably had its culmination +in middle Pliocene time. Some floras of early late Pliocene of the +southwestern United States reflect a climate slightly cooler and +more moist than the climates of the middle Pliocene. However, +late Pliocene times reflect an arid climate. The flora of the southwestern +interior basin of North America in early late to late Pliocene +was intermediate between the previous grassland floras of the +middle Pliocene and the savannah flora of upper Pliocene. Axelrod +(<i>loc. cit.</i>) suggests that this intermediate flora of the interior basin +of southwestern North America resulted from the folding of the +Cascades and uplifting of the Sierra Nevada and Peninsular ranges +to the south. The development of these mountains produced +greater aridity to the lee of the mountains, thus accounting for the +grassland-savannah flora. Pygmy mice probably originated in that +time, I judge in México, and moved northward and southward in +<span class="pagenum"><a name="Page_656" id="Page_656">[Pg 656]</a></span> +a grassland-savannah habitat that seemingly existed as far north +as what is now Meade County, Kansas (where the Sawrock fauna +lived). Further evidence for occupancy of a grassland-savannah +habitat by ancestral pygmy mice stems from the distribution of +the living species, <i>B. taylori</i>, that at present occupies territory +adjacent to parts of the Sonoran and Chihuahuan deserts. <i>B. +taylori</i> seems to be morphologically more specialized for life in an +arid grassland than was <i>B. sawrockensis</i>.</p> + +<p>The geographic range of ancestral pygmy mice possibly extended +farther south in late Pliocene time than the range of <i>B. musculus</i> +does now. Anyhow, <i>B. sawrockensis</i> of the early late Pliocene +dwelt in a more mesic type of habitat than <i>B. musculus</i> does, and +such habitat may have existed from the Pacific lowlands of Central +America to the Caribbean lowlands of northern South America (see +Duellman, 1958:136, and Dunn, 1940:156) during late Pliocene +times. An ancestral stock of hesperomine mice, not greatly different +from <i>Baiomys</i>, may have emigrated from the North American +continent into South America across the continuous land connection, +which Simpson (1950:395) suggests was formed in the +Chapadmalalan age (= Blancan age of North American terminology). +The length of time of interchange of genes between northern +and southern populations of mice across the Central American land +connection probably was brief. Duellman (<i>op. cit.</i>:129) pointed +out that once the Panamanian portal was closed, the warm counter +equatorial current, El Niño, combined with the uplifting of the +Andes, began to produce heavy rain forests in Central America and +northern South America in late Pliocene or early Pleistocene times. +These forests presumably isolated the stock in North America from +that in South America where the latter probably evolved rapidly +into kinds that differed from one another and from <i>Baiomys</i> in +shape of body, type of pelage, and shape of skull. Internal structures +such as hyoid apparatus, auditory ossicles, and baculum remained +almost unchanged, as for example in <i>Calomys</i> now living in South +America. The present resemblance in internal morphological +features between it and <i>Baiomys</i>, I judge, reflects taxonomic relationships +more accurately than do shape and conformation of +body and skull that seem to respond more rapidly to external environmental +changes. The cranial characters distinguishing <i>Baiomys +musculus</i> from <i>Calomys laucha</i> are as follows: posterior +lacerate foramina between second, rather than first, upper molars; +parapterygoid fossa shallower; mesopterygoid fossa as wide or +<span class="pagenum"><a name="Page_657" id="Page_657">[Pg 657]</a></span> +wider, instead of narrower, than parapterygoid processes; burr for +attachment of superficial masseter muscle hypertrophied instead +of well-developed. In other cranial characters studied, the two +genera closely resemble each other. Such similarities of crania +between <i>Calomys</i> and <i>Baiomys</i> may reflect convergence, but the +total of internal and external morphological characters shared, I +think reflects true relationships.</p> + +<p><i>Peromyscus</i> has a large number of living and extinct species and +exhibits a wide range of morphological variation, whereas <i>Baiomys</i> +has a small number (7) of species and exhibits a narrow range of +morphological variation. The small number of known species of +pygmy mice suggests their conservatism in elaboration of morphological +characters. Possibly this is because the habitat, or even +the ecological niche, occupied in geological time by these mice +was restricted, geographically and in kind. If the habitat of the +pygmy mice oscillated between savannah and arid grassland, then +an hypothesis can be made possibly accounting for the origin of +species of these mice. My idea is that the geographical distribution +of <i>Baiomys</i> today reflects a predilection on the part of these +mice for a relatively uniform warm climate. Therefore, in the +past, in times of warmer continental climate, these mice moved +toward favorable habitat northward from an area in central and +northern México. In cooler periods, the mice moved southward +as habitats to the north became unfavorable.</p> + +<p>Dr. W. B. Davis (<i>in. litt.</i>) informs me that <i>B. taylori</i> was uncommon +in Brazos County, Texas, approximately 15 years ago, and +suggests that the abundance there now of this mouse and my taking +it in 1958 northward nearly to the southern border of Oklahoma +reflects a definite movement northward. Movement in the same +direction in late years has been suggested for the nine-banded armadillo +and the hispid cotton rat (Hall, 1959:373) that are associated +with warm climates to the south. These movements possibly reflect +only minor fluctuations of climate, but in a long period of +warmth movements northward would be expected to be pronounced +and extensive.</p> + +<p>Extinct species of <i>Baiomys</i> may have originated as a result of +extension northward of the geographical range and subsequent +retreat southward of the northern populations, as follows: (1) the +range of the genus moved northward in a warm period; (2) in +cooler times, most of the mice in the north disappeared and only +isolated colonies remained in small patches of remaining habitat +<span class="pagenum"><a name="Page_658" id="Page_658">[Pg 658]</a></span> +still favorable to the mice; (3) the small populations of isolated +pygmy mice after a time changed through mutations, recombinations +and subsequent selection to a degree that prevented crossbreeding +once populations from the south again moved northward +and came in contact with previously isolated stocks; (4) then +competition caused further divergence in morphological characters. +Such an hypothesis would account for the morphological differences +between the extinct <i>B. kolbi</i> and <i>B. rexroadi</i>. The extinct +<i>B. brachygnathus</i>, presumably a dweller of a xerophytic grassland, +may have had its origin from a <i>B. minimus</i>-like stock in the manner +outlined.</p> + + +<div class="caption3"><a name="FORMATION_OF_THE_RECENT_SPECIES" id="FORMATION_OF_THE_RECENT_SPECIES"></a> +FORMATION OF THE RECENT SPECIES</div> + +<p>The morphological difference between the extinct <i>B. minimus</i> +and the living <i>B. musculus</i> is not great, and musculus seems to be +the product of the <i>B. sawrockensis-B. minimus</i> line of development. +Morphological characters of the parental stock of the two living +species, <i>musculus</i> and <i>taylori</i>, may have been intermediate between +those of <i>B. minimus</i> and those of <i>B. musculus</i>. The principal part +of the range of <i>Baiomys</i> today is in México, and probably was there +through much of Pleistocene time. Extension northward of the species +and retreat southward of those northern populations of pygmy +mice would not only have left isolated populations in the north, +but would have allowed the mice that retreated south to share a +common gene pool. Therefore, populations of pygmy mice occurring +to the south in central México might be expected to maintain +a relatively high degree of heterozygosity in morphological and +behavioral characters. The occurrence of any physical or biotic +barrier that would have separated this homogeneous group would +be conducive to speciation. There is evidence that a barrier occurred +in the Pleistocene in central México sufficient to separate the +supposed interbreeding, relatively homogeneous populations of +pygmy mice. According to Sears (1955:529) and De Terra <i>et al</i>. +(1949:51), parts of the higher regions in the Valley of México, and +the transverse volcanic zone in central México were glaciated. On +the mountain Ixtaccihuatl, De Terra (<i>op. cit.</i>:52) found evidence of +four marked advances of ice, from oldest to youngest, as follows: +Salto, ice advanced to 3100 meters; Xopano, ice at 3200-3300 meters; +Trancas, ice to 3400 meters; Ayolotepito, ice to 4350 meters. The +Salto advance is correlated by De Terra (<i>loc. cit.</i>) with the Iowan +glacial period. The advance of ice down the mountain sides in +the transverse volcanic zone was accompanied by cool moist climates +<span class="pagenum"><a name="Page_659" id="Page_659">[Pg 659]</a></span> +or pluvial periods. Such climates probably altered habitat +formerly suitable for <i>Baiomys</i>. There is no record of <i>Baiomys</i> +known to me exceeding 8000 feet in elevation, although the lower +edge of the ice on Ixtaccihuatl is at approximately 15,300 feet (4600 +meters, Sears, <i>loc. cit.</i>). Presumably, the advance of ice down the +mountains forced the pygmy mice to move to lower altitudes. +Pluvial conditions possibly rendered the habitat even at lower +altitudes uninhabitable for the mice, with the result that none continued +to live in the transverse volcanic zone, but only north and +south thereof. Long-continued separation of these northern and +southern segments allowed species formation to occur. As climatic +and habitat conditions became more favorable in central México, +the two species moved back toward each other, and eventually their +geographic ranges overlapped.</p> + +<p>An analysis of external and cranial characters of pygmy mice +(see <a href="#fig12">Figure 12</a>) reveals that both species are essentially largest to +the north and smallest to the south. There are exceptions to this +cline in both species. For example, <i>B. taylori analogous</i> is a large +subspecies; it lives allopatrically in the southern part of the range +of the species. <i>B. musculus pallidus</i> is not the largest subspecies; +it lives allopatrically in the northern part of the range of the species. +In west-central México, where the two species are sympatric, +<i>B. taylori</i> is smaller than elsewhere and <i>B. musculus</i> is larger than +elsewhere. <i>B. t. analogous</i> lives in the mountains of the transverse +volcanic zone in central México. Its large size may be a result of +the cooler climate in the mountains. <i>B. t. allex</i>, the smallest subspecies, +lives sympatrically with <i>B. musculus musculus</i> at lower +elevations in west-central México. The small size of <i>allex</i> could be +a result of the warmer climate of the lower elevations. <i>B. m. pallidus</i>, +at lower elevations in southern Oaxaca, is smaller than other +subspecies of <i>musculus</i> to the south at higher elevations. <i>B. m. +musculus</i> lives at low elevations along the coast of west-central +México. Unlike <i>B. m. pallidus</i>, <i>B. m. musculus</i> is large at lower +elevations. It occurs sympatrically with <i>B. t. allex</i>. It is my idea +that during the period of separation, when the two species were +evolving, larger subspecies evolved to the north or at higher altitudes +where climates were cooler; smaller subspecies evolved to +the south or at lower elevations; the two cognate species, <i>musculus</i> +and <i>taylori</i>, made contact at lower elevations where individuals of +<i>taylori</i> may have been smallest, but individuals of <i>musculus</i> were +not the largest of the species. The differences, therefore, between +the two species in their initial contact probably were slight. Hybrids, +<span class="pagenum"><a name="Page_660" id="Page_660">[Pg 660]</a></span> +if they occurred, were probably inviable, sterile, or ill-suited +for occupancy of the habitat of either of the parental stocks. The +occurrence of hybrids, therefore, would result in what geneticists +call "gamete wastage," and any further divergence in the parental +stock, either in external characters (size and shape of body and +head), or behavior, useful in recognition of species, would be favored +by natural selection (see Dobzhansky, 1951:225; and Koopman, +1950:147). The two species seem to have diverged more in +external characters where they occur together than in areas where +they live separately (see <a href="#fig12">Figure 12</a>). The two species could be +confused if a sample of adults of <i>taylori</i> from 7 mi. S La Belle, Jefferson +County, Texas, were compared to a sample of adults of +<i>musculus</i> from Tehuantepec, Oaxaca (see <a href="#fig12">Figure 12</a>). No confusion +in species identity would arise, however, if a sample of adults +was taken from the area where the two species live together (see +<a href="#fig12">Figure 12</a>). Brown and Wilson (1956:49) pointed out that where +two closely related species occur together, characters (morphological, +ecological, physiological, or behavioral) of each species +are easily distinguished. However, where the two species are allopatric, +the two closely related species so resemble one another +that the species are not easily distinguished. This phenomenon has +been called "character displacement" by Brown and Wilson (<i>loc. +cit.</i>).</p> + +<p>In the area where the two species of pygmy mice occur together, +there seems to be a disparity in numbers between them. Hooper +(1952a:91) has recorded the collection of both <i>B. musculus</i> and +<i>B. taylori</i> in a single trap line. A series of pygmy mice collected +from San Gabriel, Jalisco, contained one <i>taylori</i> and 33 <i>musculus</i>; +another sample from La Resolana, Jalisco, had a ratio of 25 <i>taylori</i> +to 6 <i>musculus</i>. The disparity in numbers where the two species +occur together has been further substantiated by collections of the +University of Kansas. Possibly this disparity in numbers is a result +of interspecific competition. Hooper (<i>op. cit.</i>:90) pointed out +that where the range of <i>B. musculus</i> (typical of arid tropical lowlands) +meets that of <i>B. taylori</i> (typical of arid temperate highlands), +the two geographic ranges interdigitate with parts of +the range of <i>musculus</i> extending into the highlands and parts of +the range of <i>taylori</i> extending into the lowlands. In the lowlands, +<i>musculus</i> may be better adapted to environmental conditions and, +therefore, more successful in competition with <i>taylori</i> for available +habitat. The reverse situation may exist in the highlands. Also, +the fact that <i>musculus</i> is more of a diurnal animal than is <i>taylori</i> +<span class="pagenum"><a name="Page_661" id="Page_661">[Pg 661]</a></span> +may account for the difference in numbers of individuals of the +two species taken in trap lines. Many collectors set their traps in +late afternoon or evening and retrieve them in early morning. +Such a schedule might not yield many <i>musculus</i>. If interspecific +competition does occur in the area where the two species occur, +any change in habits or microhabitat by either species that would +reduce this competition would be favored by natural selection +(see Mayr, 1949:518; Lack, 1944:262-263; and Brown, 1958:154-155). +Brown (<i>op. cit.</i>:154), as I understand him, pointed out +(taking account of Gause's principle) that when two species having +similar ecological valences move into the same niche in the same +locality, one of three things must eventually happen: (<i>a</i>) the +two species occupy different geographic ranges; (<i>b</i>) they compete +and one is eventually eliminated; (<i>c</i>) the two species, because +of differentiation or specialization, exploit different aspects of the +niche. In <i>Baiomys</i>, (<i>c</i>) seems to apply. Natural selection probably +would favor a continuation of diurnal activity in <i>musculus</i> and +nocturnal activity in <i>taylori</i>, thereby preventing frequent meeting of +the two species.</p> + + +<div class="caption3"><a name="AREAS_OF_PRESENT_DIFFERENTIATION" id="AREAS_OF_PRESENT_DIFFERENTIATION"></a> +AREAS OF PRESENT DIFFERENTIATION</div> + +<p>In both species of <i>Baiomys</i>, the most distinct subspecies, <i>B. t. +allex</i> and <i>B. m. musculus</i>, occur in the area where the two species +are sympatric. Seven subspecies, or 44 per cent, occur either in +or adjacent to the transverse volcanic zone. This area is the +major area of active differentiation. Incipient subspecies are also +evident in these areas. A secondary area of differentiation is indicated +within the range of <i>B. musculus</i> in Guatemala, El Salvador +and Honduras. Three subspecies occur in this area (<i>grisescens, +handleyi</i> and <i>nigrescens</i>) and incipient subspeciation is in evidence +there.</p> + + +<div class="caption3"><a name="ZOOGEOGRAPHIC_POSITION" id="ZOOGEOGRAPHIC_POSITION"></a> +ZOOGEOGRAPHIC POSITION</div> + +<p>Hooper (1949:25) regards <i>Baiomys</i> as a member of the rodent +fauna of the arid, western Sonoran region, whereas Hershkovitz +(1958:609) suggests that <i>Baiomys</i> is a nearctic-neotropical varicant +(a kind that occurs in contiguous zoogeographic regions without +our knowing in which region the taxon originated). The findings +from my study do not contradict either of the above suggestions. +Because of the close resemblance of <i>Baiomys</i> to certain hesperomine +mice of South America, it is postulated that <i>Baiomys</i>, in more +primitive form than now, occurred farther south in past times +than it does now. Fossils show that primitive stocks of the genus +<span class="pagenum"><a name="Page_662" id="Page_662">[Pg 662]</a></span> +in late Pliocene or early Pleistocene times occurred also north +of the present range of the genus. The belt in west-central México +between nearctic and neotropical regions is the current center of +distribution of the genus and probably has been for a considerable +time.</p> + +<p><span class="pagenum"><a name="Page_663" id="Page_663">[Pg 663]</a></span></p> +<div class="fig_center"> +<a name="fig12" id="fig12"></a> +<img src="images/fig_12.png" width="718" height="502" alt="" /> +</div> + +<div class="fig_caption"><span class="smcap">Fig. 12.</span> Averages of the occipitonasal lengths of skulls of adults at 19 localities of occurrence (solid symbols) of +<i>Baiomys taylori</i>, and at 17 localities of occurrence (open symbols) of <i>Baiomys musculus</i>. Note that the occipitonasal +length decreases from north to south in each of the two species, and that in the region where the two +species occur together, west-central México, <i>B. taylori</i> is smallest and <i>B. musculus</i> is largest. Average, extremes, +number of specimens averaged (in italic type), and name of locality, from north to south for each species, are +as follows:</div> + +<table summary="species"> +<tr> +<td class="vtop"> +<div class="center"> +<i>Baiomys taylori</i><br /> +<br /> +<table summary="physical data"> +<tr><td align="left">18.0 (17.5-18.6) <i>15</i>, 9<sup>1</sup>/<sub>2</sub> mi. W New Mexico state line, Ariz.</td> +</tr> +<tr><td align="left">18.9 (18.2-19.4) <i>6</i>, 7 mi. S. La Belle, Jefferson Co., Texas.</td> +</tr> +<tr><td align="left">18.2 (17.8-18.5) <i>10</i>, San Antonio, Bexar Co., Texas.</td> +</tr> +<tr><td align="left">18.2 (18.0-18.5) <i>5</i>, 2 mi. W Miñaca, Chihuahua.</td> +</tr> +<tr><td align="left">18.0 (17.6-19.0) <i>22</i>, 6 mi. SW San Gerónimo, Coahuila.</td> +</tr> +<tr><td align="left">18.2 (18.1-18.3) <i>3</i>, Ciudad Obregón, Sonora.</td> +</tr> +<tr><td align="left">18.1 (17.4-18.5) <i>5</i>, vic. (see <a href="#Page_649">p. 649</a>) Durango, Durango.</td> +</tr> +<tr><td align="left">18.1 (17.5-18.5) <i>9</i>, Jaumavé, Tamaulipas.</td> +</tr> +<tr><td align="left">18.2 (17.7-18.9) <i>19</i>, 15 mi. N Rosario Chelé, Sinaloa.</td> +</tr> +<tr><td align="left">17.9 (17.4-18.3) <i>27</i>, vic. (see <a href="#Page_655">p. 655</a>) Altamira, Tamaulipas.</td> +</tr> +<tr><td align="left">18.3 (17.9-18.7) <i>9</i>, Valparaíso, Zacatecas.</td> +</tr> +<tr><td align="left">18.1 (18.1-18.2) <i>4</i>, Ciudad del Maíz, San Luis Potosí.</td> +</tr> +<tr><td align="left">18.6 (18.3-18.9) <i>8</i>, Tepic, Nayarit.</td> +</tr> +<tr><td align="left">18.0 (17.7-18.4) <i>18</i>, 4 mi. N, 5 mi. W León, Guanajuato.</td> +</tr> +<tr><td align="left">18.1 (17.5-18.9) <i>28</i>, 6 mi. E Querétaro, Querétaro.</td> +</tr> +<tr><td align="left">17.7 (17.1-18.1) <i>17</i>, 1 mi. SSE Ameca, Jalisco.</td> +</tr> +<tr><td align="left">17.3 (16.8-17.9) <i>10</i>, 2 mi. SSE Autlán, Jalisco.</td> +</tr> +<tr><td align="left">18.0 (17.5-18.6) <i>10</i>, 1 mi. S, 11 mi. W Zamora, Michoacán.</td> +</tr> +<tr><td align="left">17.6 (17.4-18.2) <i>8</i>, Colima, Colima.</td> +</tr> +</table></div> +</td> +<td> </td> +<td class="vtop"> +<div class="center"> +<i>Baiomys musculus</i><br /> +<br /> +<table summary="physical data"> +<tr><td align="left">20.2 (19.9-20.3) <i>6</i>, vic. (see <a href="#Page_622">p. 622</a>) Ameca, Jalisco.</td> +</tr> +<tr><td align="left">20.2 (19.9-20.3) <i>6</i>, 2 mi. SSE Autlán, Jalisco.</td> +</tr> +<tr><td align="left">19.6 (19.2-20.1) <i>6</i>, Jalapa, Veracruz.</td> +</tr> +<tr><td align="left">20.3 (19.7-20.9) <i>9</i>, Colima, Colima.</td> +</tr> +<tr><td align="left">19.5 (19.0-20.0) <i>10</i>, Cerro Gordo, Veracruz.</td> +</tr> +<tr><td align="left">19.8 (19.4-20.3) <i>6</i>, 6 mi. S Izucár de Matemores, Puebla.</td> +</tr> +<tr><td align="left">20.0 (18.8-20.5) <i>7</i>, Teotitlán, Oaxaca.</td> +</tr> +<tr><td align="left">20.1 (19.7-20.7) <i>7</i>, 1 km. NW Chapa, Guerrero.</td> +</tr> +<tr><td align="left">19.9 (19.4-20.4) <i>8</i>, 5 mi. ESE Tecpán, Guerrero.</td> +</tr> +<tr><td align="left">19.5 (19.1-20.1) <i>22</i>, 3 mi. ESE Oaxaca, Oaxaca.</td> +</tr> +<tr><td align="left">19.5 (19.1-19.9) <i>11</i>, Valley of Comitán, Chiapas.</td> +</tr> +<tr><td align="left">18.9 (18.2-20.1) <i>17</i>, Tehuantepec, Oaxaca.</td> +</tr> +<tr><td align="left">18.9 (18.4-19.7) <i>15</i>, 6 mi. NW Tonalá, Chiapas.</td> +</tr> +<tr><td align="left">19.1 (18.8-20.4) <i>10</i>, 1 mi. S Rabinal, Guatemala.</td> +</tr> +<tr><td align="left">19.7 (18.8-20.4) <i>10</i>, Lake Amatitlán, Guatemala.</td> +</tr> +<tr><td align="left">19.2 (18.4-19.8) <i>26</i>, vic. (see <a href="#Page_625">p. 625</a>) San Salvador, El Salvador.</td> +</tr> +<tr><td align="left">19.3 (18.9-19.9) <i>24</i>, 8 mi. S Condega, Estelí, Nicaragua.</td> +</tr> +</table></div> +</td> +</tr> +</table> + + +<p><span class="pagenum"><a name="Page_664" id="Page_664">[Pg 664]</a></span></p> + + +<div class="caption2"><a name="CONCLUSIONS" id="CONCLUSIONS"></a>CONCLUSIONS</div> + + +<p>1. Two Recent species, each polytypic with eight subspecies, and +five fossil species are recognized.</p> + +<p>2. The phyletic trends in the genus <i>Baiomys</i> have been from an +ancestral stock that possessed relatively brachydont teeth having +raised cingular ridges and orthodont to proödont incisors, to species +having hypsodont teeth with reduced cingular ridges and retrodont +incisors.</p> + +<p>3. Reduction of cingular ridges in pygmy mice is associated with +an existence in open grassland (more xeric than mesic), whereas, +the presence of cingular ridges is associated with an existence in a +savannah habitat (more mesic than xeric).</p> + +<p>4. Shifts of geographical range of populations of pygmy mice +at and near the periphery of their geographic range may account +for the differentiation of the extinct species.</p> + +<p>5. The two living species, <i>B. musculus</i> and <i>B. taylori</i>, are seemingly +derived from a common ancestor that in morphological structure +was intermediate between <i>B. minimus</i> and <i>B. musculus</i>.</p> + +<p>6. The living species of pygmy mice resulted from a geographic +separation, perhaps occurring in the Iowan glacial period (See De +Terra, 1949:51) in the transverse volcanic zone of central México.</p> + +<p>7. The two species are now sympatric in west central México, +where morphological characters (size and shape of body and length +of skull) differ most. Where the two species are allopatric, these +same morphological characters differ least.</p> + +<p>8. This is a documented instance of character displacement in +mammals.</p> + +<p>9. On the basis of internal morphological characters studied +(auditory ossicles, hyoid apparatus, and baculum), <i>Baiomys</i> seems +to be more closely related to a South American hesperomine, perhaps +<i>Calomys</i>, than to any North American cricetine.</p> + +<p>10. Pygmy mice were more widely distributed in the past than +they are at present. Part of the ancestral stock of the pygmy mice +may have emigrated from North America into South America in a +brief period in the Pliocene; if so, it is easy to understand why +certain South American hesperomines resemble <i>Baiomys</i>.</p> + +<p><span class="pagenum"><a name="Page_665" id="Page_665">[Pg 665]</a></span></p> + +<p>11. The combination of morphological and behavioral characters +in the living pygmy mice warrants generic status for them. If +<i>Baiomys</i> were treated as a subgenus of the genus <i>Peromyscus</i>, there +would be adequate justification for including in the genus <i>Peromyscus</i> +a number of other genera, some of them occurring in South +America. Such lumping of genera would reduce our understanding +of the natural relationships among this group of cricetine rodents.</p> +<br /> +<br /> + + +<div class="caption2"><a name="LITERATURE_CITED" id="LITERATURE_CITED"></a> +LITERATURE CITED</div> + + +<div class="smcap">Allen, J. 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Michigan, 105:1-24, 1 fig., 24 pls., 1 table, December +29.</div> +<br /> + +<div><span class="smcap">Hunsaker, D.</span>, <span class="smcap">Raun, G. G.</span>, and <span class="smcap">Swindells, J. E.</span></div> + +<div class="references">1959. Range expansion of <i>Baiomys taylori</i> in Texas. Jour. Mamm., +40:477-478, August 20.</div> +<br /> + +<span class="smcap">Koopman, K. F.</span> + +<div class="references">1950. Natural selection for reproductive isolation between <i>Drosophila +pseudoobscura</i> and <i>Drosophila persimilis</i>. Evolution, 4:135-148, +3 figs., 7 tables, June.</div> +<br /> + +<span class="smcap">Lack, D.</span> + +<div class="references">1944. Ecological aspects of species formation in passerine birds. Ibis, +86:260-286, July.</div> +<br /> + +<p><span class="pagenum"><a name="Page_669" id="Page_669">[Pg 669]</a></span></p> + +<span class="smcap">Layne, James N.</span> + +<div class="references">1959. Growth and development of the eastern harvest mouse, <i>Reithrodontomys +humulis</i>. Bull. Florida State Mus., 4:61-82, 5 figs., +April 27.</div> +<br /> + +<span class="smcap">Leopold, A. S.</span> + +<div class="references">1950. Vegetation zones of México. Ecol., 31:507-518, 1 fig., 1 table, +October.</div> +<br /> + +<div><span class="smcap">Lowery, G. H.</span>, and <span class="smcap">Dalquest, W. W.</span></div> + +<div class="references">1951. Birds from the state of Veracruz, México. Univ. Kansas Publ., +Mus. Nat. Hist., 3:531-649, 7 figs., 2 tables, October 10.</div> +<br /> + +<span class="smcap">Lukens, P. W., Jr.</span> + +<div class="references">1955. The mammals of the Chilpancingo area of the Mexican state of +Guerrero. Unpublished Master's dissertation, Texas Agricultural +and Mechanical College of Texas. 209 pp.</div> +<br /> + +<span class="smcap">Mayr, E.</span> + +<div class="references">1949. Speciation and selection. Proc. Amer. Phil. Soc., 93:514-519, +December.</div> +<br /> + +<span class="smcap">Mearns, E. A.</span> + +<div class="references">1907. Mammals of the Mexican boundary of the United States … Pt. +1, Families Didelphidae to Muridae. Bull. U. S. Nat. Mus., +56:xv + 530, 13 pls., 126 figs., numerous tables, April 13.</div> +<br /> + +<span class="smcap">Merriam, C. Hart</span> + +<div class="references">1892. Descriptions of new mammals collected by E. W. Nelson in the +states of Colima and Jalisco, México. Proc. Biol. Soc. Washington, +7:164-174, September 29.</div> +<br /> + +<span class="smcap">Moore, R. T.</span> + +<div class="references">1945. The transverse volcanic biotic province of central México and its +relationship to adjacent provinces. Trans. San Diego Soc. Nat. +Hist., 10:217-236, 1 map, 4 tables, August 31.</div> +<br /> + +<span class="smcap">Osgood, W. H.</span> + +<div class="references">1909. Revision of the mice of the American Genus <i>Peromyscus</i>. N. Amer. +Fauna, 28:1-285, 8 pls., 12 figs., several tables, April 17.</div> +<br /> + +<span class="smcap">Packard, R. L.</span> + +<div class="references">1958a. New subspecies of the rodent <i>Baiomys</i> from Central America. +Univ. Kansas Publ., Mus. Nat. Hist., 9:397-404, 2 tables, December 19.</div> + +<div class="references">1958b. The taxonomic status of <i>Peromyscus allex</i> Osgood. Proc. Biol. +Soc. Washington, 71:17-20, April 11.</div> +<br /> + +<span class="smcap">Ridgway, R.</span> + +<div class="references">1912. Color standards and color nomenclature. Published by the author, +Washington, D. C., iii + 43 pp., 53 pls.</div> +<br /> + +<span class="smcap">Rinker, G. C.</span> + +<div class="references">1954. The comparative myology of the mammalian genera <i>Sigmodon</i>, +<i>Oryzomys</i>, <i>Neotoma</i>, and <i>Peromyscus</i> (Cricetinae), with remarks +on their intergeneric relationships. Miscl. Publ. Mus. Zool., Univ. +Michigan, 83:1-124, 18 figs., 2 tables, June 4</div>. +<br /> + +<span class="smcap">Russell, R. J., Jr.</span> + +<div class="references">1952. A new subspecies of pygmy mouse, <i>Baiomys musculus</i>, from +Morelos, México. Proc. Biol. Soc. Washington, 65:21-22, January 29.</div> +<br /> + +<p><span class="pagenum"><a name="Page_670" id="Page_670">[Pg 670]</a></span></p> + +<span class="smcap">Sears, P. B.</span> + +<div class="references">1955. Palynology in southern North America, Part 4: Pleistocene Climate +in México. Bull. Geol. Soc. America, 66:521-530, 6 figs., 1 pl., +1 table, May.</div> +<br /> + +<span class="smcap">Simpson, G. G.</span> + +<div class="references">1945. The principles of classification and a classification of mammals. +Bull. Amer. Mus. Nat. Hist., 85:xvi + 350, October 5.</div> + +<div class="references">1950. History of the fauna of Latin America. Amer. Sci., 38(3):361-389, +10 figs.</div> +<br /> + +<span class="smcap">Smith, H. M.</span> + +<div class="references">1949. Herpetogeny in México and Guatemala. Ann. Association Amer. +Geogr., 39:219-238, 1 fig., 1 table, September.</div> +<br /> + +<span class="smcap">Sprague, J. M.</span> + +<div class="references">1941. A study of the hyoid apparatus of the cricetinae. Jour. Mamm., +22:296-310, 5 figs., August 14.</div> +<br /> + +<div><span class="smcap">Stickel, L. F.</span>, and <span class="smcap">Stickel, W. H.</span></div> + +<div class="references">1949. A <i>Sigmodon</i> and <i>Baiomys</i> population in ungrazed and unburned +Texas prairie. Jour. Mamm., 30:141-150, 3 tables, May 23.</div> +<br /> + +<span class="smcap">Stuart, L. C.</span> + +<div class="references">1954. A description of a subhumid corridor across northern central +America, with comments on its herpetofaunal indicators. Contrib. +Lab. Vert. Biol., Univ. Michigan, 65:1-26, 6 maps, 6 pls., March.</div> +<br /> + +<span class="smcap">Tamayo, Jorge L.</span> + +<div class="references">1949. Atlas Geografico general de México, con cartas fisicas, biologicas, +demograficas, sociales, economicas, y cartogramas, Mexico, 24 +maps, December 12.</div> +<br /> + +<span class="smcap">Thomas, O.</span> + +<div class="references">1888. On the small mammals of Duval County, Texas. Proc. Zool. +Soc. London, pp. 443-450.</div> +<br /> + +<span class="smcap">True, F. W.</span> + +<div class="references">1894. On the relationships of Taylor's Mouse, <i>Sitomys taylori</i>. Proc. +U. S. Nat. Mus., 16:757-758, February 7.</div> +<br /> + +<div><span class="smcap">Twente, J. H.</span>, and <span class="smcap">Baker, R. H.</span></div> + +<div class="references">1951. New records of mammals from Jalisco, México, from barn owl +pellets. Jour. Mamm., 32:120-121, 1 table, February 15.</div> +<br /> + +<span class="smcap">Van Gelder, R. G.</span> + +<div class="references">1959. A taxonomic revision of the spotted skunks (Genus <i>Spilogale</i>). +Bull. Amer. Mus. Nat. Hist., 117(5):229-392, 47 figs., 32 tables, +June 15.</div> +<br /> + +<span class="smcap">White, J. A.</span> + +<div class="references">1951. A practical method for mounting the bacula of small mammals. +Jour. Mamm., 32:125, February 15.</div> + +<div class="references">1953. The baculum in the chipmunks of western North America. Univ. +Kansas Publ., Mus. Nat. Hist., 5:611-631, 19 figs., December 1.</div> +<br /> + +<span class="smcap">Wilson, R. W.</span> + +<div class="references">1937. Pliocene rodents of western North America. Carnegie Inst. Washington, +Publ. 487:21-73, 2 figs., July 23.</div> +<br /> + +<div><span class="smcap">Wood, A. E.</span>, and <span class="smcap">Wilson, R. W.</span></div> + +<div class="references">1936. A suggested nomenclature for the cusps of the cheek teeth of +rodents. Jour. Paleon., 10:388-391, 2 figs.</div> +<br /> +<br /> + +<p><i>Transmitted March 4, 1960.</i></p> +<br /> +<br /> + +<div class="fig_center"> +<img src="images/square.png" width="16" height="17" alt="" /><br /> +28-3030<br /> +<br /> +<br /> +</div> + +<p><span class="pagenum"><a name="Page_i" id="Page_i">[Pg i]</a></span></p> + +<div class="caption2"><a name="PUBLICATIONS" id="PUBLICATIONS"></a> +UNIVERSITY OF KANSAS PUBLICATIONS</div> + +<div class="caption2">MUSEUM OF NATURAL HISTORY</div> + + +<p>Institutional libraries interested in publications exchange may obtain this +series by addressing the Exchange Librarian, University of Kansas Library, +Lawrence, Kansas. Copies for individuals, persons working in a particular +field of study, may be obtained by addressing instead the Museum of Natural +History, University of Kansas, Lawrence, Kansas. There is no provision for +sale of this series by the University Library, which meets institutional requests, +or by the Museum of Natural History, which meets the requests of individuals. +However, when individuals request copies from the Museum, 25 cents should +be included, for each separate number that is 100 pages or more in length, for +the purpose of defraying the costs of wrapping and mailing.</p> + +<p>* An asterisk designates those numbers of which the Museum's supply (not the Library's +supply) is exhausted. Numbers published to date, in this series, are as follows:</p> + +<table summary="Publications"> +<tr><td class="vtop"> Vol. 1.</td> + <td class="text_lf" colspan="2">Nos. 1-26 and index. Pp. 1-638, 1946-1950.</td> +</tr> + +<tr> + <td class="vtop">*Vol. 2.</td> + <td colspan="2">(Complete) Mammals of Washington. By Walter W. Dalquest. Pp. 1-444, 140 + figures in text. April 9, 1948.</td> +</tr> +<tr> + <td class="vtop"> Vol. 3.</td> + <td class="text_rt vtop">*1.</td> + <td>The avifauna of Micronesia, its origin, evolution, and distribution. By Rollin + H. Baker, Pp. 1-359, 16 figures in text. June 12, 1951.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">*2.</td> + <td>A quantitative study of the nocturnal migration of birds. By George H. + Lowery, Jr. Pp. 361-472, 47 figures in text. June 29, 1951.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">3.</td> + <td>Phylogeny of the waxwings and allied birds. By M. Dale Arvey. Pp. 473-530, + 49 figures in text, 13 tables. October 10, 1951.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">4.</td> + <td>Birds from the state of Veracruz, Mexico. By George H. Lowery, Jr., and + Walter W. Dalquest. Pp. 531-649, 7 figures in text, 2 tables. October 10, 1951.</td> +</tr> +<tr> + <td> </td> + <td class="text_lf" colspan="2">Index. Pp. 651-681.</td> +</tr> +<tr> + <td class="vtop">*Vol. 4.</td> + <td colspan="2">(Complete) American weasels. By E. Raymond Hall. Pp. 1-466, 41 plates, 31 + figures in text. December 27, 1951.</td> +</tr> +<tr> + <td class="vtop"> Vol. 5.</td> + <td colspan="2">Nos. 1-37 and index. Pp. 1-676, 1951-1953.</td> +</tr> +<tr> + <td class="vtop">*Vol. 6.</td> + <td colspan="2">(Complete) Mammals of Utah, <i>taxonomy and distribution</i>. By Stephen D. + Durrant. Pp. 1-549, 91 figures in text, 30 tables. August 10, 1952.</td> +</tr> +<tr> + <td class="vtop"> Vol. 7.</td> + <td class="text_rt vtop">*1.</td> + <td>Mammals of Kansas. By E. Lendell Cockrum. Pp. 1-303. 73 figures in + text, 37 tables. August 25, 1952.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">2.</td> + <td>Ecology of the opossum on a natural area in northeastern Kansas. By Henry + S. Fitch and Lewis L. Sandidge. Pp. 305-338, 5 figures in text. August + 24, 1953.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">3.</td> + <td>The silky pocket mice (Perognathus flavus) of Mexico. By Rollin H. Baker. + Pp. 339-347, 1 figure in text, February 15, 1954.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">4.</td> + <td>North American jumping mice (Genus Zapus). By Philip H. Krutzch. Pp. + 349-472, 47 figures in text, 4 tables. April 21, 1954.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">5.</td> + <td>Mammals from Southeastern Alaska. By Rollin H. Baker and James S. + Findley. Pp. 473-477. April 21, 1954.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">6.</td> + <td>Distribution of Some Nebraskan Mammals. By J. Knox Jones, Jr. Pp. 479-487. + April 21, 1954.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">7.</td> + <td>Subspeciation in the montane meadow mouse. Microtus montanus, in Wyoming + and Colorado. By Sydney Anderson. Pp. 489-506, 2 figures in text. + July 23, 1954.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">8.</td> + <td>A new subspecies of bat (Myotis velifer) from southeastern California and + Arizona. By Terry A. Vaughan. Pp. 507-512. July 23, 1954.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">9.</td> + <td>Mammals of the San Gabriel mountains of California. By Terry A. Vaughan. + Pp. 513-582. 1 figure in text, 12 tables. November 15, 1954.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">10.</td> + <td>A new bat (Genus Pipistrellus) from northeastern Mexico. By Rollin H. + Baker. Pp. 583-586. November 15, 1954.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">11.</td> + <td>A new subspecies of pocket mouse from Kansas. By E. Raymond Hall. Pp. + 587-590. November 15, 1954.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">12.</td> + <td>Geographic variation in the pocket gopher, Cratogeomys castanops, in Coahuila, + Mexico. By Robert J. Russell and Rollin H. Baker. Pp. 591-608. + March 15, 1955.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">13.</td> + <td>A new cottontail (Sylvilagus floridanus) from northeastern Mexico. By Rollin + H. Baker. Pp. 609-612. April 8, 1955.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">14.</td> + <td>Taxonomy and distribution of some American shrews. By James S. Findley. + Pp. 613-618. June 10, 1955.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">15.</td> + <td>The pigmy woodrat, Neotoma goldmani, its distribution and systematic position. + By Dennis G. Rainey and Rollin H. Baker. Pp. 619-624, 2 figures in + text. June 10, 1955.</td> +</tr> +<tr> + <td> </td> + <td class="text_lf" colspan="2">Index. Pp. 625-651.</td> +</tr> +<tr> + <td class="vtop"> Vol. 8.</td> + <td class="text_rt vtop">1.</td> + <td>Life history and ecology of the five-lined skink, Eumeces fasciatus. By Henry + S. Fitch. Pp. 1-156, 26 figures in text. September 1, 1954.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">2.</td> + <td>Myology end serology of the Avian Family Fringillidae, a taxonomic study. + By William B. Stallcup. Pp. 157-211, 23 figures in text, 4 tables. November + 15, 1954.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">3.</td> + <td>An ecological study of the collared lizard (Crotaphytus collaris). By Henry + S. Fitch. Pp. 213-274, 10 figures to text. February 10, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">4.</td> + <td>A field study of the Kansas ant-eating frog, Gastrophryne olivacea. By Henry + S. Fitch. Pp. 275-306, 9 figures in text. February 10, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">5.</td> + <td>Check-list of the birds of Kansas. By Harrison E. Tordoff. Pp. 307-359, 1 + figure in text. March 10, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">6.</td> + <td>A population study of the prairie vole (Microtus ochrogaster) in northeastern + Kansas. By Edwin P. Martin. Pp. 361-416, 19 figures in text. April 2, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">7.</td> + <td>Temperature responses in free-living amphibians and reptiles of northeastern + Kansas. By Henry S. Fitch. Pp. 417-476, 10 figures in text, 6 tables. June + 1, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">8.</td> + <td>Food of the crow, Corvus brachyrhynchos Brehm, in south-central Kansas. By + Dwight Platt. Pp. 477-498. 4 tables. June 8, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">9.</td> + <td>Ecological observations on the woodrat, Neotoma floridana. By Henry S. + Fitch and Dennis G. Rainey. Pp. 499-533, 3 figures in text. June 12, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">10.</td> + <td>Eastern woodrat, Neotoma floridana: Life history and ecology. By Dennis + G. Rainey. Pp. 535-646, 12 plates, 13 figures in text. August 15, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_lf" colspan="2">Index. Pp. 647-675.</td> +</tr> +<tr> + <td class="vtop"> Vol. 9.</td> + <td class="text_rt vtop">1.</td> + <td>Speciation of the wandering shrew. By James S. Findley. Pp. 1-68, 18 figures + in text. December 10, 1955.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">2.</td> + <td>Additional records and extensions of ranges of mammals from Utah. By + Stephen D. Durrant, M. Raymond Lee, and Richard M. Hansen. Pp. 69-80. + December 10, 1955.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">3.</td> + <td>A new long-eared myotis (Myotis evotis) from northeastern Mexico. By Rollin + H. Baker and Howard J. Stains. Pp. 81-84. December 10, 1955.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">4.</td> + <td>Subspeciation in the meadow mouse, Microtus pennsylvanicus, in Wyoming. + By Sydney Anderson. Pp. 85-104, 2 figures in text. May 10, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">5.</td> + <td>The condylarth genus Ellipsodon. By Robert W. Wilson. Pp. 105-116, 6 + figures In text. May 19, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">6.</td> + <td>Additional remains of the multituberculate genus Eucosmodon. By Robert + W. Wilson. Pp. 117-123, 10 figures in text. May 19, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">7.</td> + <td>Mammals of Coahuila, Mexico. By Rollin H. Baker. Pp. 125-335, 75 figures + in text. June 15, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">8.</td> + <td>Comments on the taxonomic status of Apodemus peninsulae, with description + of a new subspecies from North China. By J. Knox Jones, Jr. Pp. 337-346, + 1 figure in text, 1 table. August 15, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">9.</td> + <td>Extensions of known ranges of Mexican bats. By Sydney Anderson. Pp. + 347-351. August 15, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">10.</td> + <td>A new bat (Genus Leptonycteris) from Coahuila. By Howard J. Stains. + Pp. 353-356. January 21, 1957.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">11.</td> + <td>A new species of pocket gopher (Genus Pappogeomys) from Jalisco, Mexico. + By Robert J. Russell. Pp. 357-361. January 21, 1957.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">12.</td> + <td>Geographic variation in the pocket gopher, Thomomys bottae, in Colorado. + By Phillip M. Youngman. Pp. 363-385, 7, figures in text. February 21, 1958.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">13.</td> + <td>New bog lemming (genus Synaptomys) from Nebraska. By J. Knox Jones, + Jr. Pp. 385-388. May 12, 1958.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">14.</td> + <td>Pleistocene bats from San Josecito Cave, Nuevo León, México. By J. Knox + Jones, Jr. Pp. 389-396. December 19, 1958.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">15.</td> + <td>New Subspecies of the rodent Baiomys from Central America. By Robert L. + Packard. Pp. 397-404. December 19, 1958.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">16.</td> + <td>Mammals of the Grand Mesa, Colorado. By Sydney Anderson. Pp, 405-414, + 1 figure in text. May 20, 1959.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">17.</td> + <td>Distribution, variation, and relationships of the montane vole, Microtus montanus. + By Emil K. Urban. Pp. 415-511. 12 figures in text, 2 tables. + August 1, 1959.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">18.</td> + <td>Conspecificity of two pocket mice, Perognathus goldmani and P. artus. By + E. Raymond Hall and Marilyn Bailey Ogilvie. Pp. 513-518, 1 map. + January 14, 1960.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">19.</td> + <td>Records of harvest mice, Reithrodontomys, from Central America, with + description of a new subspecies from Nicaragua. By Sydney Anderson and + J. Knox Jones, Jr. Pp. 519-529. January 14, 1960.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">20.</td> + <td>Small carnivores from San Josecito Cave (Pleistocene), Nuevo León, México. + By E. Raymond Hall. Pp. 531-538, 1 figure in text. January 14, 1960.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">21.</td> + <td>Pleistocene pocket gophers from San Josecito Cave, Nuevo León, México. + By Robert J. Russell. Pp. 539-548, 1 figure in text. January 14, 1960.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">22.</td> + <td>Review of the insectivores of Korea. By J. Knox Jones, Jr., and David + H. Johnson. Pp. 549-578. February 23, 1960.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">23.</td> + <td>Speciation and evolution of the pygmy mice, genus Baiomys. By Robert + L. Packard. Pp. 579-670, 4 plates, 12 figures in text. June 16, 1960.</td> +</tr> +<tr> + <td> </td> + <td class="text_lf" colspan="2">Index will follow.</td> +</tr> +<tr> + <td class="vtop">Vol. 10.</td> + <td class="text_rt vtop">1.</td> + <td>Studies of birds killed in nocturnal migration. By Harrison B. Tordoff and + Robert M. Mengel. Pp. 1-44, 6 figures in text, 2 tables. September 12, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">2.</td> + <td>Comparative breeding behavior of Ammospiza caudacuta and A. maritime. + By Glen E. Woolfenden. Pp. 45-75, 6 plates, 1 figure. December 20, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">3.</td> + <td>The forest habitat of the University of Kansas Natural History Reservation. + By Henry S. Fitch and Ronald R. McGregor. Pp. 77-127, 2 plates, 7 figures + in text, 4 tables. December 31, 1956.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">4.</td> + <td>Aspects of reproduction and development in the prairie vole (Microtus ochrogaster). + By Henry S. Fitch, Pp. 129-161, 8 figures in text, 4 tables. December 19, 1957.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">5.</td> + <td>Birds found on the Arctic slope of northern Alaska. By James W. Bee. + Pp. 163-211, pls. 9-10, 1 figure in text. March 12, 1958.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">6.</td> + <td>The wood rats of Colorado; distribution and ecology. By Robert B. Finley, + Jr. Pp. 213-552, 34 plates, 8 figures in text, 35 tables. November 7, 1958.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">7.</td> + <td>Home ranges and movements of the eastern cottontail in Kansas. By Donald + W. Janes. Pp. 553-572, 4 plates, 3 figures in text. May 4, 1959.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">8.</td> + <td>Natural history of the salamander, Aneides hardyi. By Richard F. Johnston + and Schad Gerhard. Pp. 573-585. October 8, 1959.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">9.</td> + <td>A new subspecies of lizard, Cnemidophorus sacki, from Michoacán, México. + By William E. Duellman. Pp. 587-598, 2 figures in text. May 2, 1960.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">10.</td> + <td>A taxonomic study of the Middle American Snake, Pituophis deppei. By + William E. Duellman. Pp. 599-612, 1 plate, 1 figure in text. May 2, 1960.</td> +</tr> +<tr> + <td> </td> + <td class="text_lf" colspan="2">Index will follow.</td> +</tr> +<tr> + <td class="vtop"> Vol. 11.</td> + <td class="text_rt vtop">1.</td> + <td>The systematic status of the colubrid snake, Leptodeira discolor Günther. + By William E. Duellman. Pp. 1-9, 4 figs. July 14, 1958.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">2.</td> + <td>Natural history of the six-lined racerunner, Cnemidophorus sexlineatus. By + Henry S. Fitch. Pp. 11-62, 9 figs., 9 tables. September 19, 1958.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">3.</td> + <td>Home ranges, territories, and seasonal movements of vertebrates of the + Natural History Reservation. By Henry S. Fitch, Pp. 68-326, 6 plates, 24 + figures in text, 8 tables. December 12, 1958.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">4.</td> + <td>A new snake of the genus Geophis from Chihuahua, Mexico. By John M. + Legler. Pp. 327-334, 2 figures in text. January 28, 1959.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">5.</td> + <td>A new tortoise, genus Gopherus, from north-central Mexico. By John M. + Legler. Pp. 335-343. April 24, 1959.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">6.</td> + <td>Fishes of Chautauqua, Cowley and Elk counties, Kansas. By Artie L. + Metcalf. Pp. 345-400, 2 plates, 2 figures in text, 10 tables. May 6, 1959.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">7.</td> + <td>Fishes of the Big Blue River Basin, Kansas. By W. L. Minckley. Pp. 401-442, + 2 plates, 4 figures in text, 5 tables. May 8, 1959.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">8.</td> + <td>Birds from Coahuila, México. By Emll K. Urban. Pp. 443-516. August 1, 1959.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">9.</td> + <td>Description of a new softshell turtle from the southeastern United States. + By Robert G. Webb. Pp. 517-525, 2 pls., 1 figure in text, August 14, 1959.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">10.</td> + <td>Natural history of the ornate box turtle, Terrapene ornata ornata Agassiz. By + John M. Legler. Pp. 527-669, 16 pls., 29 figures in text. March 7, 1960.</td> +</tr> +<tr> + <td> </td> + <td class="text_lf" colspan="2">Index will follow.</td> +</tr> +<tr> + <td class="vtop"> Vol. 12.</td> + <td class="text_rt vtop">1.</td> + <td>Functional morphology of three bats: Eumops, Myotis, Macrotus. By Terry + A. Vaughan. Pp. 1-153, 4 plates, 24 figures in text. July 8, 1959.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">2.</td> + <td>The ancestry of modern Amphibia: a review of the evidence. By Theodore + H. Eaton, Jr. Pp. 155-180, 10 figures in text. July 10, 1959.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">3.</td> + <td>The baculum in microtine rodents. By Sydney Anderson. Pp. 181-216, 49 + figures in text. February 19, 1960.</td> +</tr> +<tr> + <td> </td> + <td class="text_rt vtop">4.</td> + <td>A new order of fishlike Amphibia from the Pennsylvanian of Kansas. By + Theodore H. Eaton, Jr., and Peggy Lou Stewart. Pp. 217-240, 12 figures inv + text. May 2, 1960.</td> +</tr> +<tr> + <td> </td> + <td class="text_lf" colspan="2">More numbers will appear In volume 12.</td> +</tr> +</table> +<br /> +<br /> + +<div class="trans_notes"> +<div class="caption2"><a name="Transcribers_Notes" id="Transcribers_Notes"></a> +Transcriber's Notes</div> + +<p>The text presented is that of the original printed version except for +the revisions below and a few assumed typesetting errors. The subsection +headers under "<a href="#VARIATION_WITH_AGE">VARIATION WITH AGE</a>" were +converted to italic only to match the rest. All other section title +formatting retained as printed. The words Miscellaneous and Monograph +were abbreviated as Miscl. and Mongr. respectively. Except for the two +variant spellings of one word (Mexico/México) which were retained, the +most prevalent form of accented words was used.</p> + +<p>Both decimal and whole and fractional part of numbers (i.e., 9<sup>1</sup>/<sub>2</sub>) +were retained as printed. Where a relative size as +indicated for illustrations (i.e., × 3), they may not be correct for the +displayed images as resolution of monitors vary. Each set of footnotes were +placed at the end of each species account. The list of KU Publications were +compiled after the article's text.</p> + + +<div class="caption2">Typographical Corrections</div> + +<table summary="typos"> +<tr> + <td class="brdbt2">Page</td> + <td> </td> + <td class="brdbt2">Correction</td> +</tr> +<tr> + <td>591</td> + <td> </td> + <td>proödent ⇒ proödont</td> +</tr> +<tr> + <td>694</td> + <td> </td> + <td>hesperomyines ⇒ hesperomines</td> +</tr> +</table> +<br /> +</div> +<br /> +<br /> +</div><!-- End Book --> + + + + + + + +<pre> + + + + + +End of the Project Gutenberg EBook of Speciation and Evolution of the Pygmy +Mice, Genus Baiomys, by Robert L. 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