Geographic Variation in the Pocket Gopher, Thomomys bottae, in Colorado

by Phillip M. Youngman

Fig. 3. Thomomys b. howelli, holotype, Grand Junction, 4600 ft., Mesa Co., Colorado. No. 75684 USNM, ♀.

Fig. 4. Thomomys b. pervagus, Espanola, 5000 ft., Rio Arriba Co., New Mexico. No. 133614 USNM, ♀.

Fig. 5. Thomomys b. cultellus, Fishers Peak, 8000 ft., Las Animas Co., Colorado. No. 129285 USNM, ♀.

Fig. 6. Thomomys b. internatus, Salida, 7050 ft., Chaffee Co., Colorado. No. 2757 ERW, ♀.

Fig. 7. Thomomys b. rubidus, holotype, 2-9/10 mi. E Cañon City, Fremont Co., Colorado. No. 72954, ♀.

Thomomys bottae rubidus new subspecies

Holotype.—Adult female, skin and skull, number 72954, Museum of Natural History, University of Kansas, trapped by Richard S. Miller and Phillip M. Youngman, original number 253 (PMY), 2-9/10 miles east of Cañon City, 5344 feet, Fremont County, Colorado, March 17, 1957.

Distribution.—Known only from Garden Park in Cañon City and from the type locality (see fig. 1).

Distinctive characters.—Dark (Reddish Brown 5YR 3/3); size large (see measurements); skull large; rostrum wide; zygomatic arches rounded and broadly spreading (see fig. 7); alveolar length of upper maxillary tooth-row small.

Comparisons.—From topotypes of T. b. internatus, T. b. rubidus differs as follows: uniformly darker; skull averages larger in all measurements, except alveolar length of upper maxillary tooth-row, which is smaller; rostrum proportionately wider and tapered anteriorly; zygomatic arches more rounded; bullae more rounded in lateral view.