[Pg 81]

University of Kansas Publications

Museum of Natural History

Volume 9, No. 3, pp. 81-84

December 10, 1955

A New Long-eared Myotis (Myotis Evotis)

from Northeastern México

BY


ROLLIN H. BAKER AND HOWARD J. STAINS

University of Kansas

Lawrence

1955

[Pg 82]

University of Kansas Publications, Museum of Natural History

Editors: E. Raymond Hall, Chairman, A. Byron Leonard,
Robert W. Wilson

Volume 9, No. 3, pp. 81-84

Published December 10, 1955

University of Kansas

Lawrence, Kansas

PRINTED BY

FERD VOILAND, JR., STATE PRINTER

TOPEKA, KANSAS

1955


25-8617

[Pg 83]

A New Long-eared Myotis (Myotis Evotis)

From Northeastern México

BY

ROLLIN H. BAKER AND HOWARD J. STAINS

Long-eared bats obtained by field parties from the University of
Kansas in the Mexican states of Coahuila, Nuevo León, and Tamaulipas,
are found to belong to the species, Myotis evotis, but are not
referable to any named subspecies. They are named and described
as follows:

Myotis evotis auriculus new subspecies

Type.—Female, adult, skin and skull; No. 55110, Univ. Kansas Mus. Nat.
Hist.; 10 mi. W and 2 mi. S Piedra, 1200 ft., Sierra de Tamaulipas, Tamaulipas;
9 June 1953; obtained by Gerd H. Heinrich, original number 7061.

Distribution.—Coastal foothills and adjacent mountains of northeastern
México from central Coahuila south and east to central Veracruz.

Diagnosis.—Size medium (see measurements), ears small for the species;
color dark, upper parts (j14) Ochraceous-Tawny (color terms are after Ridgway,
Color Standards and Color Nomenclature, Washington, D. C., 1912),
underparts Warm Buff, ears pale; skull large, teeth large, mandible long.

Comparison.—From Myotis evotis evotis (H. Allen), from Colorado, Wyoming,
and Montana, M. e. auriculus differs in: Ears averaging shorter; color
darker and richer; ears paler and contrasting less, in color, with pelage; skull
larger in all measurements taken except that of least interorbital constriction;
forehead, when viewed laterally, rising more abruptly, because frontal region is
more inflated; teeth larger.

Remarks.—Myotis evotis auriculus, although no larger externally
than M. e. evotis, has a larger skull, which in lateral view has a more
abruptly rising forehead. The teeth, especially the first upper premolars,
of auriculus are noticeably larger than those of evotis. The
first two lower premolars are sub-equal in auriculus whereas in evotis
the first lower premolar usually is larger. The mandible, in relation
to the greatest length of the skull, is longer in auriculus (ratio, 71-74)
than in evotis (ratio, 67-71).

Coahuilan specimens, although assigned to auriculus, are slightly
paler (upper parts (16) Ochraceous-Tawny; underparts (e) Light
Buff) and have less abruptly rising foreheads than do the bats from
Tamaulipas. In these features, the Coahuilan animals are somewhat
intermediate between typical auriculus and evotis. The bat from[Pg 84]
Nuevo León, in both color and degree of slope of forehead, is intermediate
between those from Coahuila and those from Tamaulipas.

A bat from Perote, Veracruz, identified as Myotis evotis chrysonotus
(J. A. Allen) [=M. e. evotis] by Miller and Allen (U. S. Nat.
Mus., Bull. 144:118 and 120-121, May 25, 1928) is here assigned to
M. e. auriculus. Measurements given by these authors indicate that
this bat has a large skull, which is characteristic of this subspecies.
Another specimen, similarly assigned by these authors and from
the San Luis Mountains in northwestern Chihuahua, seems to be
M. e. evotis, although the published measurements (loc. cit.) show
that this bat tends toward auriculus in size of skull and mandible.

All specimens were taken in mist nets stretched over water. Those
from Coahuila were snared over a concrete water tank situated
near the base of low hills in mixed mesquite and chaparral. In
Nuevo León, one bat was netted over a small pond around which
grew some low trees in an intermontane valley in the Sierra Madre
Oriental. In Tamaulipas two bats were caught in a mist net stretched
across a narrow, brush-bordered arroyo in the Sierra de Tamaulipas.
One adult male weighed 7.0 grams; average and extreme weights
of 7 adult, non-pregnant females were 6.8 (5.2-8.0). Females taken
on March 25 and 26 were not pregnant; one obtained on June 20
was lactating. Funds for financing field work were made available
by the Kansas University Endowment Association and the National
Science Foundation.

Measurements.—Measurements, in millimeters, of the holotype and another
female (No. 55111 KU) from the type locality and 3 females (Nos. 44726,
44729-30 KU) from Coahuila, respectively, are: total length, 94, 93, 97, 86, 96;
length of tail vertebrae, 43, 42, 41, 39, 45; length of hind foot, 9.5, 9, 10,
10, 8; height of ear from notch, 20, 20, 20, 18, 20; length of forearm, 37.9,
38.4, 40.2, 37.3, 38.5; greatest length of skull, 16.1, 16.4, 16.2, 15.8, 16.1;
condylobasal length, 15.4, 15.4, 15.6, 15.0, 15.4; zygomatic breadth, 9.7, 9.9,
10.1, 9.4, 9.9; least interorbital constriction, 3.9, 3.8, 3.9, 3.7, 3.7; breadth of
braincase, 7.5, 7.6, 7.5, 7.5, 7.6; occipital depth, 5.9, 5.9, 5.5, 5.7, 5.6; palatal
length, 8.5, 8.7, 8.7, 8.7, 8.9; mastoid breadth, 8.2, 8.4, 8.3, 8.2, 8.3; breadth
across third upper molars, 6.1, 6.2, 6.3, 6.1, 6.1; length of maxillary tooth-row,
6.5, 6.5, 6.7, 6.6, 6.6; length of mandible, 11.5, 11.8, 11.9, 11.2, 11.7;
length of mandibular tooth-row, 8.0, 8.0, 8.1, 8.1, 8.1.

Specimens examined.—Total, 8, all in the University of Kansas Museum of
Natural History. Coahuila: 4 mi. W Hacienda La Mariposa, 2300 ft., 5 (2
alcoholics). Nuevo León: Iturbide, 5000 ft., Sierra Madre Oriental, 1.
Tamaulipas: 10 mi. W and 2 mi. S Piedra, 1200 ft., Sierra de Tamaulipas, 2.

Transmitted April 16, 1955.