University of Kansas Publications
Museum of Natural History



Volume 7, No. 8, pp. 507-512



July 23, 1954

A New Subspecies of Bat (Myotis velifer)

from Southeastern California and Arizona

BY

TERRY A. VAUGHAN

University of Kansas

Lawrence

1954

University or Kansas Publications, Museum of Natural History



Editors: E. Raymond Hall, Chairman, A. Byron Leonard,

Robert W. Wilson





Volume 7, No. 8, pp. 507-512

Published July 23, 1954





University of Kansas

Lawrence, Kansas

PRINTED BY

FERD VOILAND. JR., STATE PRINTER

TOPEKA, KANSAS

1954



25-3727

A New Subspecies of Bat (Myotis velifer) from Southeastern California

and Arizona

BY

TERRY A. VAUGHAN

The first specimens of Myotis velifer from California were taken in
1909 by C. L. Camp at Needles, San Bernardino County (Grinnell, Univ.
California Publ. Zool., 12:266, March 20, 1914), and subsequently this
bat was recorded from farther south in the lower Colorado River Valley
at the Riverside Mountains, Riverside County (Stager, Jour. Mamm.,
20:226, May 14, 1939). West of the Rocky Mountains the species is known
to occur also in at least the southern two-thirds of Arizona,
southwestern New Mexico, and is recorded from Thistle Valley, Utah, on
the basis of two young specimens in alcohol (Miller and Allen, Bull. U.
S. Nat. Mus., 144:87, May 25, 1928). Through comparisons made possible
by the acquisition, in the last few years, of mammals from many parts of
Mexico by the Museum of Natural History of the University of Kansas, it
became evident that Myotis velifer in California and Arizona was an
heretofore unnamed subspecies. It may be known as

Myotis velifer brevis new subspecies

TABLE 1.—Measurements, in Millimeters, of Myotis velifer

Remarks.—Miller and Allen (op. cit. :90) considered specimens of
Myotis velifer from Roosevelt, Arizona, to be intergrades between M.
v. velifer and M. v. incautus because the color varied greatly and
certain pale individuals resembled incautus. These workers regarded
specimens from southern Arizona as nearly typical examples of M. v.
velifer. I have examined the specimens from Roosevelt, Arizona, and
many from various localities in the southern part of the state, and was
impressed by the large amount of color varia[Pg 511]tion. Marked variation in
color at a single locality, however, is known in other bats. Benson
(Jour. Mamm., 30:50, February 14, 1949), for example, found striking
variation in Myotis volans in California. The specimens of Myotis
velifer from Roosevelt, Arizona, referred to M. v. velifer by Miller
and Allen (op. cit. :90), actually average significantly smaller than
specimens of this subspecies from Mexico, and than specimens of the
large subspecies M. v. incautus from the Great Plains, and therefore,
with reference to size, are not intergrades between these subspecies.
All of the Arizonan material is here referred to M. v. brevis.

The "bald spot," that is to say, the sparsely furred area between the
shoulders, which is characteristic of this species, reaches its most
extreme condition in Myotis velifer brevis. In most of thirty-five
specimens taken in mid-June, 1953, in California, the nape of the neck,
the interscapular area, and a connected area extending laterally onto
each shoulder are so lightly furred that the skin shows through
conspicuously. In one male of this series a strip approximately four
millimeters wide extending along the mid-dorsal line from between the
shoulders to the rump is mostly devoid of hair. These sparsely-furred
areas are less evident in live animals than in study skins and specimens
in alcohol, because the back of the head in life lies against the
depression between the shoulders and conceals most of the thinly furred
areas.

The pelage of Myotis velifer brevis is shorter than that of either M.
v. velifer or M. v. incautus and gives the impression of being less
dense. The dorsal hairs average approximately 4.5 millimeters long in
M. v. brevis taken 35 miles north of Blythe, Riverside County,
California, in May, eight millimeters in M. v. velifer collected at
Las Vigas, Veracruz, in January, and six millimeters in M. v. incautus
taken four and one half miles southwest of Sun City, Barber County,
Kansas, in November. More than seasonal differences in length of pelage
is indicated by measurements of additional specimens of each subspecies
taken at different times of the year.

Considering its extensive geographic range and its occurrence in many
contrasting environments, Myotis velifer varies little; and the
variation that does occur is continuous. The change from the large, dark
Mexican subspecies to the small, pale Arizonan subspecies is gradual.
The reason may lie in the ecology of M. velifer. It seems that there
are few barriers separating populations. Waterless areas and regions
lacking suitable roosting places such as fissures in cliffs and outcrops
of rocks, caves and buildings, may exclude the species from certain
areas, but there are few areas of any great size within[Pg 512] the range of
the species that lack these features. Also, these bats are strong
fliers; even between fairly distant colonies there may be considerable
gene flow. The geographic variation observed probably is the result of
adaptation, on the part of populations in different parts of the range
of the species, to different environments. The lack of any effective
barriers except possibly distance between populations tends to limit
subspeciation and to cause gradual variation between subspecies. M. v.
peninsularis, the subspecies at the southern tip of Baja California, is
not considered in this discussion. So far as known, however, that
subspecies is completely isolated from the mainland populations of M.
velifer.