A New Pocket Gopher (Genus Thomomys)

From Wyoming and Colorado

Type.—Male, adult, skull and skin, no. 25628 Mus. Nat. Hist. Univ. Kansas;
from 8 mi. N and 19-½ mi. E Savery, 8800 ft., Carbon County, Wyoming; obtained
on July 19, 1948, by George M. Newton; original no. 4.

Range.—Sierra Madre Mountain Range of southern Wyoming and northern
Colorado.

Diagnosis.—Size small (see measurements); color dark, upperparts in worn
pelage of July darker than (near, n) Raw Umber (capitalized terms are of
Ridgway, Color Standards and Color Nomenclature, Washington, D. C., 1912)
and in fresh pelage of August between (near, 16') Prout's Brown and Mummy
Brown; skull small; relative to basilar length, skull narrow across rostrum,
zygomata and mastoids; nasals short and posteriorly truncate; premaxillae extending
behind nasals; temporal lines faint and divergent posteriorly.

Comparisons.—From Thomomys talpoides rostralis (North Platte River Valley,
SW of Saratoga, Wyoming), the subspecies to the east and south, T. t.
meritus differs in: Lesser size, darker color, smaller and slenderer skull. The
slenderness is especially noticeable in the breadth across the zygomata, mastoids,
and rostrum. From Thomomys talpoides clusius (topotypes), the subspecies
to the north and west, T. t. meritus differs in: Color much darker; rostrum
longer; skull narrower across mastoids and zygomata; tympanic, and also
mastoid, bullae smaller. Resemblance to T. t. clusius is shown in the narrowness
of the skull interorbitally and in the shortness of the tooth-row.

Measurements.—Average and extreme measurements of seven adult males
and five adult females, from the type locality, are as follows: Total length,
204 (193-226), 207 (193-210); length of tail, 56 (46-68), 56 (50-63);
length of hind foot, 27.6 (26-30), 27.4 (27-28); basilar length, 30.7 (29.0-33.0),
30.1 (29.5-30.7); zygomatic breadth, 20.4 (18.9-21.6), 19.5 (18.8-20.0);
least interorbital breadth, 6.2 (5.8-6.6), 6.1 (5.9-6.3); mastoidal breadth,
17.9 (16.9-18.5), 17.2 (16.7-17.6); length of nasals, 13.7 (12.4-14.7), 13.2
(12.8-13.9); breadth of rostrum, 7.0 (6.5-7.5), 6.9 (6.7-7.3); length of rostrum,
16.3 (15.3-17.5), 15.8 (15.3-16.1); alveolar length of maxillary tooth-row,
7.1 (6.9-7.3), 7.1 (6.8-7.5).

Specimens examined.—Total number 26 and unless otherwise indicated in
the Museum of Natural History of the University of Kansas.

Wyoming.—Carbon County: Savery (8 mi. N and 19-½ mi. E, 8800 ft., 12;
7 mi. N and 17 mi. E, 8300 ft., 1; 6 mi. N and 12-½ mi. E, 8400 ft., 1; 6 mi. N
and 13-½ mi. E, 8400 ft., 2; 6 mi. N and 14-½ mi. E, 8350 ft., 1; 5 mi. N and
3 mi. E, 6800 ft., 1; 4 mi. N and 8 mi. E, 7800 ft., 7300 ft., 3; 4 mi. N and
10 mi. E, 7800 ft., 3) 24.

Colorado—Routt Co. ?: Elkhead Mts., 20 mi. SE Slater, 2 (U. S. B. S.).