A New Subspecies of Pocket Mouse

from Kansas

Holotype.—Female, subadult (P4 moderately worn), skin with skull, No.
13045, Univ. Kansas Mus. Nat. Hist.; 4-1/2 mi. NE Danville, Harper Co., Kansas;
December 1, 1939; obtained by Sam Tihen; original No. 99 of J. A. Tihen.

Range.—South-central Kansas south at least into Dewey County, Oklahoma.

Diagnosis.—Size small; upper parts Ochraceous-Buff (capitalized color terms
after Ridgway, Color Standards and Color Nomenclature, Washington, D. C.,
1912) heavily suffused with black; postauricular patches and a band 8 mm
wide on each side Ochraceous-Buff; subauricular spot, underparts, and forefeet
white; hind feet slightly dusky; tail brownish above and white below.
Skull small; tympanic bullae small; rostrum wide; skull indistinguishable from
that of P. f. flavescens from the same latitude in western Kansas.

Comparisons.—Perognathus flavescens cockrumi averages approximately 12
per cent smaller in linear measurements than the more northern Perognathus
flavescens perniger Osgood (from Knox, Stanton and Cumming counties, Nebraska)
but color of upper parts is essentially the same. From the more western
Perognathus flavescens flavescens Merriam (from Seward, Hamilton and Morton
counties, Kansas), cockrumi differs in being darker in all parts of the pelage
except on the underparts which are white in both subspecies; the parts of the
hairs that are Ochraceous-Buff in cockrumi are Light Ochraceous-Buff in flavescens;
the back of cockrumi is blackish instead of yellowish. From the more
southern Perognathus flavescens copei Rhoads (topotypes examined but not at
hand as I write), cockrumi differs in duller more blackish (less bright and less
reddish) upper parts. From Perognathus merriami gilvus, of more southern
distribution, the new subspecies differs in much smaller tympanic bullae and
wider rostrum.

Measurements.—The type, a male (35331/47596 U.S.B.S., from Cairo,
Kansas, showing some wear on P4), and another male (60165 K. U., from
Barber Co., Kansas, showing much wear on P4) measure, respectively: Total
length, 114, 120, 124; tail, 51, 55, 58; hind foot, 17, 17, 18; occipitonasal
length,——, 21.0, 21.6; condylobasal length (condyles to anterior end of
premaxillae), 18.5, 18.6, 19.3; frontonasal length,——, 14.1, 14.3; mastoidal
breadth, 10.5, 11.2, 11.2; length of bulla, 6.8, 7.1, 6.8; interorbital breadth, 4.7,[Pg 590]
4.8, 5.1; alveolar length of upper molariform tooth-row, 3.1, 3.1, 3.0; interparietal
breadth, 4.3. 4.6, 4.7.

Specimens examined.—Total, 10 distributed as follows:

Kansas: Ellsworth Co.: 1-1/2 mi. S Wilson, 1. Pratt Co.: Cairo, 3 (U.S.
B.S.). Barber Co.: Plum Thicket Farm [= 1 mi. E and 3 mi. N Sharon], 4.
Harper Co.: 4-1/2 mi. N Danville, 1.

Oklahoma: Dewey Co.: 6 mi. W and 1/2 mi. S Canton, 1.