The Pocket Gophers (Genus Thomomys) of Utah / University of Kansas Publications, Museum of Natural History, Vol. 1 No. 1

by Stephen David Durrant

Specimens examined.—Total, 41, distributed as follows: Summit County: 2 mi. S junction Bear River and Haydens Fork, 2 (C. M.); N base, Gilbert Peak, 10,000 ft., 1 (U. S. N. M.); Smith and Moorehouse Creek, 2; Bald Peak, 25 mi. NE Kamas, 15 (8, M. V. Z.; 6, C. M.). Duchesne County: Petty Mountain, 15 mi. N Mountain Home, 9,500 ft., 6 (C. M.). Wasatch County: Wolf Creek Pass, 18 mi. NW Hanna, 1 (U. S. A. C.); Lost Lake, Uinta Mountains, 10 (B. Y. U.); Current Creek, Uinta Mountains, 1 (U. S. N. M.). Carbon County: Forks, Sunnyside, 9,000 ft., 3.

Additional records.—Summit County: Uinta Mountains, 6 (see Bailey, 1915:114).

Thomomys talpoides pygmaeus Merriam

Thomomys pygmaeus Merriam, Proc. Biol. Soc. Washington, 14:115. July 19, 1901.

Thomomys talpoides pygmaeus Davis, The Recent mammals of Idaho, p. 252, The Caxton Printers, Ltd., Caldwell, Idaho, April 5, 1939.

Type.—Male, adult, skin and skull, No. 55251, U. S. National Museum (Biological Surveys Collection); 10 mi. NE Montpelier, in open sagebrush of Transition Zone, 6,600 ft., Bear County, Idaho; July 29, 1893; collected by Vernon Bailey: original number 4150 (after Merriam, type not seen: see, also, Bailey, 1915:109).

Range.—Limited to Daggett County.

Diagnosis.—Size: Small (see measurements). Color: Upper parts near Bister slightly mixed with black, grading over sides and flanks to Ochraceous Buff on underparts; postauricular patches small and dusky; hind feet white; front feet dusky, being white only at base of claws; chin and nose dusky; tail brown, lighter below and tipped with white. Skull: Very small, slender and smooth; nasals short and slender; zygomatic arches weak and not widely spreading; rostrum narrow; extension of premaxillae posterior to nasals short; parietal ridges hardly noticeable; interparietal large; extension of supraoccipital posterior to lambdoidal suture long; tympanic bullae actually small, but relatively large; basioccipital narrow; interpterygoid space narrow and acutely angled; upper incisors markedly recurved; molariform teeth relatively large.

Comparisons.—This small pocket gopher can be distinguished from all other members of Thomomys talpoides occurring in Utah by remarkably small size, and slender, weak, small skull with strongly recurved upper incisors.