Two New Pocket Gophers from Wyoming
and Colorado

Type.—Female, adult, skull and skin, no. 17096 Mus. Nat. Hist., Univ.
Kansas; from 1 mi. E Laramie, 7164 ft., Albany County, Wyoming; obtained on
July 16, 1945, by C. Howard Westman; original no. 320.

Range.—Southern Wyoming and south in the mountains of Colorado to the
Arkansas River but not including the Colorado River drainage except in Grand
County and part of Routt County.

Diagnosis.—Size medium (see measurements); upper parts ranging from
between Cinnamon-Rufous and Hazel (capitalized terms are of Ridgway, Color
Standards and Color Nomenclature, Washington, D. C., 1912) in the eastern
part of the range to between Argus Brown and Brussels Brown in the western
part of the range; sides Cinnamon-Rufous; throat whitish; remainder of under-parts
whitish, in many specimens tipped with Ochraceous-Buff; feet and tail
whitish; rostrum long; nasals ordinarily truncate posteriorly; temporal ridges
nearly parallel; interpterygoid space broadly V-shaped.[Pg 4]

Comparisons.—From Thomomys talpoides clusius (topotypes), T. t. rostralis
differs in: Body longer; color more reddish (lighter with less brownish
and more ochraceous); rostrum both longer and broader, actually and also in
relation to length of the skull; skull broader interorbitally; upper molariform
tooth-row longer; tympanic bullae less inflated. For comparison with T. t. attenuatus
to the east, see the account of that subspecies.

From Thomomys talpoides macrotis (topotypes) to the southeast, T. t. rostralis
differs in: Body shorter; upper parts slightly more ochraceous and less
grayish; skull averaging smaller in all measurements except that interorbital
region is broader and rostrum and upper molariform tooth-row are longer;
nasals truncate versus emarginate, and consistently shorter; basilar length
consistently less in specimens of equal age; mastoidal breadth less in 16 of 17
specimens of rostralis; temporal ridges parallel instead of divergent posteriorly;
exposed parts of upper incisors shorter; tympanic bullae more angular antero-laterally.

From Thomomys talpoides fossor (specimens from Rico, Silverton, Hermit
and Pagosa Springs, all in Colorado), the subspecies to the southward, T. t. rostralis
differs in: Longer body; lighter color of upper parts; nasals truncate
rather than rounded posteriorly; temporal ridges more nearly parallel (less divergent
posteriorly); rostrum longer (averaging longer and broader); skull
wider across zygomatic arches in 11 of 12 specimens of rostralis.

Specimens examined.—Total number, 168. Unless otherwise indicated,
those from Colorado are in the United States National Museum, Biological
Surveys Collection, and those from Wyoming are in the Museum of Natural
History of the University of Kansas.

Colorad.. Routt Co.: Hahns Peak, 2; Hayden, 1. Jackson Co. Pearle,
North Park, 9000 ft., 2; Canadian Creek, North Park, 6; 5 mi. E Canadian
Creek, 1; Rabbit Ear Mts., Arapaho Pass, 5. Larimer Co.: Elkhorn, 7000 ft.,
1; Estes Park, 7. Grand Co.: Coulter, 4. Boulder Co.: Longs Peak, 3; Gold
Hill (the skin only; skull does not belong), 1; 3 mi. S Ward, 9000 ft., 10
(K. U.); 5 mi. W Boulder, 7. Gilpin Co.: Blackhawk (U. S. N. M.), 2.
Jefferson Co.: Golden, 1; Golden foothills, 7300 ft., 1. Park Co.: Como,
South Park, 9800 ft., 1. El Paso Co.: Cascade, 1 (too young for certain sub-specific
identification).

Wyoming. Carbon County: 13 mi. E and 6 mi. S Saratoga, 8500 ft., 1;
14 mi. E and 6 mi. S Saratoga, 8800 ft., 1; 7 mi. S and 11 mi. E Saratoga,
5; 8 mi. S and 6 mi. E Saratoga, 10; 10 mi. N and 14 mi. E Encampment, 8000 ft.,
2; 10 mi. N and 16 mi. E Encampment, 8000 ft., 1; 8 mi. N and 16 mi.
E Encampment, 8400 ft., 10. Albany Co.: 2 ¼  mi. ESE Browns Peak, 10300
ft., 7; 3 mi. ESE Browns Peak 10000 ft., 5; 2 mi. S Browns Peak, 10600 ft.,
7; 3 mi. S Browns Peak, 1; 2 mi. E and ½   mi. S Medicine Bow Peak, 10800 ft.,
2; 5 mi. N Laramie, 7200 ft., 1; 1 mi. E Laramie, 7164 ft., 18; Laramie Mts.,
10 mi. E Laramie (8500 ft., 2; 9000 ft., 1), 3 (U. S. B. S.); 5  ½  9; mi. ESE
Laramie, 8500 ft., 4; 8 mi. E and 4 mi. S Laramie, 8600 ft., 5; 8 mi. E and 6
mi. S Laramie, 8500 ft., 1; 15 mi. SE Laramie, Pole Mtn., 8200 ft., 3 (U. S. B. S.);
1 mi. SSE Pole Mtn., (8250 ft., 4; 8350 ft., 6), 10; 1 mi. S Pole Mtn.,
8350 ft., 2; 2 mi. SW Pole Mtn., 8300 ft., 6; 2  ½  mi. S Pole Mtn., 8340 ft., 1;
3 mi. S Pole Mtn., 1; Woods P. O., 2 (U. S. N. M.); Fort Russell, 1 (U. S. N. M.);
Sherman, 2 (U. S. N. M.).

Additional records.—Bailey (N. Amer. Fauna, 39:101, 112, November 15,
1915) has recorded the following specimens, which on geographic grounds,
would presumably be referable to Thomomys talpoides rostralis. Colorado:
Estes Park (referred by Bailey, p. 101, to T. t. clusius), 1; Colorado City, 1;
Colorado Springs, 2 ½  mi. N, 6000 ft., 1; Colorado Springs, east of Palmer
Park, 1; Montgomery, 3; Nederland, 4; Teller County Divide, 1. These specimens
have not been examined by us.

Thomomys talpoides attenuatus new subspecies

Type.—Male, adult, skull and skin, no. 15095 Mus. Nat. Hist., Univ. Kansas;
from 3 ½  mi. W Horse Creek Post Office, 7000 ft., Laramie County, Wyoming;
obtained on July 16, 1945, by Henry W. Setzer; original no. 629.

Range.—Southeastern Wyoming from Niobrara County south into Weld
County, Colorado.[Pg 6]

Diagnosis.—Size small; color pale (whitish); skull smooth and, relative to
its length, slender; rostrum relatively long; nasals truncate posteriorly; middle
parts of zygomatic arches straight; temporal ridges low and more widely
separated in middle extent than at anterior or posterior ends; tympanic bullae
rounded and moderately inflated; interpterygoid space V-shaped.

Comparisons.—From Thomomys talpoides bullatus (topotypes) to the northward,
T. t. attenuatus differs in smaller size, lighter (less brownish, more
whitish) color, smaller and slenderer skull. In detail, some cranial features
diagnostic of attenuatus, when compared with bullatus, are: Anterolateral
angle of zygoma less nearly a right angle; temporal ridges bowed outward at
middle, instead of straight, and farther apart posteriorly than anteriorly instead
of nearly parallel; sides of basioccipital nearly straight instead of concave.

From Thomomys talpoides cheyennensis (holotype and Wyoming specimens
from: Pine Bluff; 1 mi. W Pine Bluffs, 5000 ft.; 12 mi. N and ½  mi. W Pine
Bluffs) to the eastward, T. t. attenuatus differs in smaller size throughout and
more slender skull. The two subspecies are indistinguishable in color.

From Thomomys talpoides macrotis (topotypes) to the southward, T. t. attenuatus
differs in smaller size, slightly lighter (less brownish and more
whitish) color, smaller and slenderer skull.

From Thomomys talpoides rostralis (specimens from the type locality) to
the westward, T. t. attenuatus differs in smaller size; lighter (grayer, less
brownish) color, smaller and less angular skull.

From Thomomys talpoides clusius (topotypes) to the northwestward, T. t.
attenuatus differs in shorter body, slightly grayer color, less width across mastoid
region of skull, smaller tympanic bullae, and more obtuse anterolateral
angle on zygoma.

Specimens examined.—Total number, 44, and unless otherwise indicated in
the Museum of Natural History of the University of Kansas.

Wyoming. Niobrara County: 10 mi. N Hatcreek Post Office, 5300 ft., 1.
Platte Co.: 5 mi. SW Wheatland, 1 (U. S. B. S.). Goshen Co.: Little Bear
Creek, 20 mi. SE Chugwater, 1 (U. S. B. S.). Laramie Co.: 5 mi. W and 1
mi. N Horse Creek P. O., 7200 ft., 1; 3 ½ mi. W Horse Creek P. O., 7000 ft., 6;
2 ¹/₅ mi. W Horse Creek P. O., 6600 ft., 1; 2 mi. W Horse Creek P. O., 6600 ft., 2;
Horse Creek 6500 ft., 1; 3 mi. E Horse Creek P. O., 6400 ft., 5; 6 mi. W Islay,
2 (U. S. B. S.); 2 mi. S and ½  mi. E Pine Bluffs, 5200 ft., 1; 7 mi. W
Cheyenne, 6500 ft., 1; Cheyenne, 7 (U. S. N. M.); 1 mi. S and 4 ½ mi. E
Cheyenne, 5200 ft., 1; 2 mi. S and 9 ½ mi. E Cheyenne, 5200 ft., 3; Arcola, 5200
ft., 4.[Pg 7]

Colorado. Weld Co.: Pawnee Buttes, 5300 ft., 1 (U. S. B. S.). Logan Co.:
Chimney Canyon, 10 mi. NE Avalo, 5100 ft., 5 (U. S. B. S.).

Museum of Natural History, University of Kansas, Lawrence. Transmitted
January 15, 1951.[Pg 8]