A New Species of Wood Rat (Neotoma) from Northeastern Mexico

Produced by Chris Curnow, Dianna Adair, Joseph Cooper and
the Online Distributed Proofreading Team at
http://www.pgdp.net









  UNIVERSITY OF KANSAS PUBLICATIONS
  MUSEUM OF NATURAL HISTORY

  Volume 14, No. 11, pp. 139-143
  April 30, 1962

  A New Subspecies of Wood Rat
  (Neotoma) from Northeastern Mexico

  BY

  TICUL ALVAREZ

  UNIVERSITY OF KANSAS
  LAWRENCE
  1962




  UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

  Editors: E. Raymond Hall, Chairman, Henry S. Fitch,
  Theodore H. Eaton, Jr.


  Volume 14, No. 11, pp. 139-143
  Published April 30, 1962


  UNIVERSITY OF KANSAS
  Lawrence, Kansas


  PRINTED BY
  JEAN M. NEIBARGER, STATE PRINTER
  TOPEKA, KANSAS
  1962


  29-2891




A New Subspecies of Wood Rat (Neotoma) from Northeastern Mexico

BY

TICUL ALVAREZ


The White-throated woodrat, _Neotoma albigula_, has been known
previously from the Mexican state of Tamaulipas by only eight
individuals reported by Goldman (N. Amer. Fauna, 31:37, October 19,
1910), which were assigned to _Neotoma albigula leucodon_ (type
locality, city of San Luis Potosí, México). Additional specimens from
southwestern Tamaulipas, obtained in recent years by representatives of
the Museum of Natural History, along with specimens from parts of Nuevo
León and Coahuila, represent an unnamed subspecies, which is named and
described as follows:


=Neotoma albigula subsolana= new subspecies

     _Type._--Male, adult, skin and skull, No. 56950, Museum of Natural
     History, The University of Kansas, from Miquihuana, 6400 ft.,
     Tamaulipas; obtained on July 20, 1953, by Gerd H. Heinrich,
     original number 7553B.

     _Geographic distribution._--Sierra Madre Oriental from southeastern
     Coahuila to southwestern Tamaulipas.

     _Diagnosis._--Over-all size small for species (see measurements),
     but tail, maxillary tooth-row and incisive foramina relatively
     long; upper parts dark (individual hairs banded subterminally with
     cinnamon and tipped with grayish, yielding an over-all color of
     grayish brown); lips gray, especially anteriorly and medially;
     alveoli of incisors narrow (4.8-5.2); posterior branch of
     premaxilla extending only slightly behind nasals; rostrum short;
     braincase broad; mastoid breadth averaging 51.1 (47.8-52.7) per
     cent of basilar length.

     _Comparisons._--_Neotoma albigula subsolana_, differs from
     topotypes of _N. a. leucodon_, the subspecies geographically
     adjacent to the southwest, as follows: size smaller, especially
     length of palatal bridge (6.9-8.1 instead of 8.2-9.6), alveolar
     length of maxillary tooth-row (8.3-8.9 instead of 8.8-9.7), and
     greatest length of auditory bulla (7.3-7.9 instead of 8.2-8.9);
     mastoid breadth relatively greater, 51.1 (47.8-52.7) instead of
     47.0 (45.5-49.1) per cent of basilar length; posterior process of
     premaxilla extending only slightly beyond posterior border of
     nasals; auditory bulla conspicuously smaller; upper parts darker,
     especially middorsally; over-all color grayish instead of
     ochraceous or yellowish; lips gray instead of nearly white.

     _Neotoma albigula subsolana_ differs from _N. a. albigula_,
     geographically adjacent to the northwest (specimens from Pima
     County, Arizona) as follows: size averaging slightly larger, except
     length of nasals; mastoid breadth averaging 18.8 (17.9-20.2)
     instead of 17.9 (17.7-18.2), its ratio to basilar length therefore
     greater, 51.1 (47.8-52.7) instead of 49.4 (47.9-50.0); zygomatic
     arches expanded posteriorly instead of nearly parallel as in
     _albigula_; interparietal longer and narrower; mesopterygoid fossa
     broader; auditory bulla slightly smaller; upper parts distinctly
     darker.

_Remarks._--_N. a. subsolana_ is characterized by the combination of
small size, dark color, small auditory bulla and relatively broad
braincase. Typical specimens have been collected only at higher
elevations in the Sierra Madre Oriental where no other species of
_Neotoma_ is known to occur.

Intergradation between _N. a. subsolana_ and _N. a. leucodon_ occurs at
lower elevations on the west side of the Sierra Madre Oriental as shown
by specimens from nine miles southwest of Tula, Tamaulipas, and Sierra
Guadalupe, Coahuila, from which places some specimens are paler than
others, approaching _leucodon_ in color, and are slightly larger than
typical _subsolana_. Specimens assigned to _leucodon_ from vicinity of
Presa Guadalupe and from 1 to 6 kilometers south of Matehuala, San Luis
Potosí, are typical of that subspecies in measurements but are darker
than topotypes.

_N. a. subsolana_ intergrades with _N. a. albigula_ in southeastern
Coahuila (specimens from 6 to 9 miles east of Hermanas and from Panuco)
where some individuals average paler and smaller than topotypes of
_subsolana_ and some have skulls that combine characters of _subsolana_
and _albigula_. These specimens, which were referred to _N. a. leucodon_
by Baker (Univ. Kansas Publ., Mus. Nat. Hist., 9:281-282, June 15,
1956), are assigned to _subsolana_ on the basis of relatively dark
upperparts and broad mesopterygoid fossa (narrow in only one specimen).

On geographic grounds, specimens not studied by me from Municipio de
Galeana, Nuevo León (Koestner, Great Basin Nat., 2:13, 1941), and those
from Jaumave, Tamaulipas (Goldman, N. Amer. Fauna, 31:37, October 19,
1910), probably are referable to _N. a. subsolana_.

The subspecific name _subsolana_ (Latin adjective for eastern) is
proposed for this woodrat because of its eastern geographic occurrence.

     _Measurements._--Average and extreme measurements of nine topotypes
     (6 males and 3 females) are as follows: total length, 338
     (315-370); length of tail-vertebrae, 157 (130-182); length of hind
     foot, 35 (33-37); length of ear from notch, 31 (29-34); basilar
     length, 36.5 (34.7-39.2); zygomatic breadth, 23.9 (22.5-25.0);
     interorbital constriction, 5.5 (5.7-6.2); length of nasals, 15.5
     (15.2-16.5); length of incisive foramina, 9.4 (8.8-10.1); length of
     palatal bridge, 7.7 (6.9-8.1); alveolar length of maxillary
     tooth-row, 8.7 (8.3-8.9); length of auditory bulla, 7.6 (7.3-7.9);
     mastoid breadth, 18.7 (17.9-20.2).

     _Specimens examined._--A total of 124 (all from Mus. Nat. Hist.,
     Univ. Kansas) from: COAHUILA: 6 mi. E Hermanas, 1; 9 mi. E
     Hermanas, 1; Panuco, 3000 ft., 4; 1 mi. S, 4 mi. W Bella Unión,
     7000 ft., 3; 3 mi. S, 3 mi. E Bella Unión, 6750 ft., 1; 6 mi. E, 4
     mi. S Saltillo, 7500 ft., 5; 7 mi. S, 4 mi. E Bella Unión, 7200
     ft., 3; 14 mi. W, 1 mi. N San Antonio de las Alazanas, 6500 ft., 2;
     12 mi. S, 2 mi. E Arteaga, 7500 ft., 5; north slope Sierra
     Guadalupe, 10 mi. S, 5 mi. W General Cepeda, 6500 ft., 26; 7 mi. S,
     1 mi. E Gómez Farías, 6500 ft., 3; 8 mi. N La Ventura, 5500 ft., 1.
     NUEVO LEON: Iturbide, Sierra Madre Oriental, 5000 ft., 10; Laguna,
     1; 9 mi. S Aramberri, 3900 ft., 3; 1 mi. W Doctor Arroyo, 5800 ft.,
     4. TAMAULIPAS: Miquihuana, 6400 ft., 22; Joya Verde, 35 km. SW Cd.
     Victoria (on Jaumave Road), 3800 ft., 2; Nicolás, 56 km. NW Tula,
     5500 ft., 10; Tajada, 23 mi. NW Tula, 5200 ft., 2; 9 mi. SW Tula,
     3900 ft., 15.

     _Comparative material._--_N. a. albigula_, 10 specimens (all KU)
     from: ARIZONA: 4 mi. S, 5 mi. E Continental, 4; 7 mi. E Tucson,
     2500 ft., 1; 30 mi. S Tucson, 1; 14 mi. S, 3 mi. E Continental, 1;
     Sta. Catalina Mts., south slope Molino basin, 4200 ft., 2; Santa
     Rita Mts., northwest slope, near Sta. Rita Range, 4300 ft., 1.

     _N. a. leucodon_, 46 specimens (in Mus. Nat. Hist., Univ. Kansas,
     unless otherwise noted) from: SAN LUIS POTOSI: 6 km. S Matehuala,
     13 (LSU); 1 km. S Matehuala, 2 (LSU); 7 km. W Presa de Guadalupe, 5
     (LSU); Presa de Guadalupe, 4 (LSU); 8 mi. SW Ramos, 6700 ft., 3; 10
     mi. NE San Luis Potosí, 6000 ft., 2; San Luis Potosí, 9 (USNM);
     Hda. La Parada, 8 (USNM).

I am grateful to Prof. E. Raymond Hall and Mr. J. Knox Jones, Jr., for
permission to examine critical specimens and for helpful suggestions. I
am grateful also to Dr. George H. Lowery, Jr., of the Louisiana State
University (LSU) and to Dr. David H. Johnson and Dr. Richard H. Manville
of the United States National Museum (USNM) for the loan of specimens.
Gerd H. Heinrich (in 1953) and Percy L. Clifton (in 1961) collected for
the Museum of Natural History the Tamaulipan specimens herein reported.
Fieldwork was supported by the Kansas University Endowment Association.
Laboratory phases of the study were made when the author was a half-time
Research Assistant supported by grant No. 56 G 103 from the National
Science Foundation.

     _Transmitted February 21, 1962._

29-2891


       *       *       *       *       *

     Transcriber Note:

     Italic text is denoted by _underscores_
     Bold text is denoted by =equal signs=