SUMMARY

A study of 249 specimens of Thomomys bottae from Colorado reveals six subspecies in the state. T. b. aureus and T. b. howelli occupy the Colorado Plateau Region in the western and southwestern parts of the state. T. b. internatus, T. b. cultellus, T. b. pervagus, and the newly named T. b. rubidus occupy part of the Southern Rocky Mountain Region and a narrow strip of the Great Plains.

The greatest amount of geographic variation, in Thomomys bottae in Colorado, occurs in the ecotone between the grassland and coniferous forest at the edge of the Great Plains, and in the ecotone between the Piñon, juniper, and sage of the Colorado Plateau and the Coniferous forest of the southern Rocky mountains.

Table 1. Measurements, in Millimeters, of Thomomys bottae

Unless otherwise noted, specimens are adults from Colorado

Sex Catalog number or number of individuals averaged Total length Tail Hind foot Condylobasal length Nasal length Zygomatic breadth Squamosal breadth Length of rostrum Breadth of rostrum Alveolar length of upper max. tooth-row Least interorbital breadth

Thomomys bottae howelli, holotype

♀ 75684[1] sad. 219 71 29 37.3 11.1 23.7 20.0 14.5 8.5 7.7 6.6

Thomomys bottae aureus, Bedrock

♀ 2982[2] 217 59 31 40.4 13.8 24.3 20.6 16.7 8.6 9.2 6.8

♀ 3013[2] 210 60 29 38.7 13.0 24.4 20.4 15.7 8.1 8.9 7.0

♂ 2997[2] 242 73 33 44.7 15.4 28.4 22.8 15.7 10.1 9.0 7.2

Coventry

♀ 6 av. 222 61 31 39.0 12.1 25.4 20.3 15.2 7.8 8.2 6.8

Max. 229 63 33 40.0 12.8 25.8 20.6 15.6 8.2 8.5 7.0

Min. 217 58 30 38.3 11.4 25.0 19.3 14.7 7.5 8.0 6.6

♂ 3 av. 259 70 35 46.5 15.0 29.3 22.7 17.8 9.2 9 5 6.7

Max. 270 76 36 48.3 16.0 31.9 23.7 18.0 9.3 9.6 6.9

Min. 250 65 35 45.5 14.4 27.6 22.2 17.6 9.2 8.0 6.4

Ashbaugh's Ranch and 15 mi. W Cortez

♀ 7 av. 225 67 28 39.0 13.7 24.4 20.2 16.1 8.0 8.3 6.3

Max. 238 75 31 40.6 14.7 25.0 20.7 16.5 8.5 8.7 6.8

Min. 216 55 26 37.8 12.9 23.6 19.7 15.5 7.8 7.9 6.1

♂ 4 av. 247 73 31 44.2 15.9 27.7 22.1 18.6 9.2 8.4 6.4

Max. 252 80 34 45.2 16.7 28.8 22.3 19.8 9.6 8.8 6.7

Min. 244 67 30 43.7 15.5 27.0 21.7 18.0 8.8 8.0 6.2

Cortez

♀ 5120[3] 224 56 28 38.1 12.3 .... 19.5 15.4 7.5 7.6 6.5

5121[3] 220 68 31 38.3 11.6 24.2 19.6 15.1 7.6 8.0 6.7

♂ 5124[3] 257 81 33 44.4 15.4 29.5 22.2 18.6 8.9 8.6 6.5

♂ 5119[3] 215 62 28 42.0 14.0 27.9 22.1 17.9 8.2 8.6 6.4

Mesa Verde (combined)

♀ 5 av. 221 63 30 39.0 12.6 24.7 20.2 16.0 8.0 8.2 6.7

Max. 235 66 32 40.4 13.7 25.6 21.1 17.3 8.7 8.5 7.1

Min. 212 61 28 38.1 12.0 24.1 19.5 15.0 7.7 7.9 6.4

♂ 3 av. 246 74 32 43.7 14.9 27.8 22.3 18.3 8.8 8.9 6.6

Max. 252 79 33 45.0 15.2 28.4 23.0 18.5 9.0 9.0 6.8

Min. 238 69 31 42.0 14.7 27.5 21.2 18.2 8.7 8.9 6.3

1 mi. N La Plata

♂ 72966[4] 236 70 31 45.4 15.6 29.4 23.3 20.2 8.8 8.5 6.5

3 mi. W Durango

♀ 3 av. 225 65 28 40.1 13.1 25.7 21.0 16.6 8.1 8.3 6.5

Max. 230 67 29 40.4 13.5 25.8 21.2 16.8 8.4 8.5 6.6

Min. 219 63 28 39.9 13.0 25.7 20.6 16.5 8.4 8.1 6.4

♂ 70054[4] 262 87 35 45.0 15.6 27.9 22.7 19.7 9.3 9.8 6.4

♂ 70055[4] 248 79 31 43.3 14.0 27.6 22.1 17.1 8.7 8.2 6.2

12 mi. W Pagosa Springs

♀ 72971[4] 217 65 27 39.1 12.8 .... 20.0 15.4 7.4 8.7 6.2

♂ 72970[4] 238 70 29 42.7 15.0 27.5 21.8 17.2 8.8 8.3 6.5

Thomomys bottae pervagus, Antonito

♀ 133668[1] sad. 208 69 29 37.3 12.9 23.1 18.2 15.8 7.5 8.0 6.9

Espanola, New Mexico

♀ 133616[1] 249 82 38 41.1 .... 24.6 20.0 16.3 8.2 8.1 7.1

♀ 133619[1] 216 65 32 40.6 .... 24.9 19.3 .... 8.0 8.0 6.8

♂ 58293[1] 244 76 31 44.0 16.1 26.9 21.2 18.3 8.8 8.1 6.6

Thomomys bottae internatus, Salida

♀ 11 av. 219 67 31 38.6 13.4 23.2 19.5 15.4 7.6 7.8 6.5

Max. 242 80 34 40.4 14.2 25.0 20.2 16.2 8.1 8.4 6.9

Min. 196 45 29 37.6 12.9 21.9 18.8 14.8 7.3 7.0 6.3

♂ 3 av. 247 74 32 42.9 16.1 25.1 20.9 18.0 8.2 8.0 6.3

Max. 248 74 33 43.7 16.3 26.4 21.7 18.1 8.8 8.1 6.4

Min. 247 74 32 42.2 15.9 25.8 20.5 17.9 7.9 7.9 6.3

12 mi. N Cañon City

♀ 72945[4] 230 81 28 38.1 13.0 22.6 19.4 15.0 7.9 8.0 6.7

♀ 72947[4] 228 74 27 38.7 14.0 23.6 19.8 15.9 8.2 8.1 6.8

1 mi. W Coaldale

♀ 70042[4] 224 70 30 38.1 13.1 23.5 19.5 15.6 7.7 7.5 6.6

5 mi. S Cotopaxi

♀ 72932[4] 224 65 27 39.1 13.8 24.3 20.4 15.5 7.7 7.5 6.5

♂ 72925[4] 250 74 29 44.0 16.2 27.5 22.8 18.7 9.0 8.1 6.1

9 mi. SSW Colorado Springs

♀ 72942[4] 225 77 29 38.8 14.1 23.3 20.2 15.4 7.8 8.3 6.7

72943[4] 219 70 28 37.7 13.5 23.0 19.7 14.8 7.6 8.4 6.8

2-1/2 mi. S Wetmore

♂ 70053[4] 250 81 30 42.5 16.7 26.3 22.3 17.7 8.5 7.9 5.9

200 yards E St. Charles River, 8 mi. W Pueblo

♀ 73497[4] 226 69 30 39.3 13.9 24.9 20.5 15.7 7.7 7.9 7.2

♀ 73498[4] 216 64 29 38.0 12.9 24.2 20.1 15.1 7.7 7.4 6.7

St. Charles Mesa

♀ 4860[3] 222 70 29 38.2 13.5 .... 19.3 15.9 8.2 7.5 6.5

♂ 4864[3] 240 72 33 43.1 15.8 .... 21.4 17.6 9.2 7.9 6.7

11 mi. WNW Gardner

♀ 70052[4] 227 64 28 37.9 13.0 22.5 18.8 14.8 7.3 8.0 6.7

1-1/2 mi. S Redwing

♀ 72940[4] 227 73 28 39.0 13.1 23.1 18.8 15.6 7.8 8.0 6.8

1 mi. E La Veta

♂ 70049[4] 254 88 32 42.4 15.1 27.5 21.8 17.3 8.4 8.2 6.5

♂ 70044[4] 239 80 32 42.3 16.5 27.8 22.0 17.9 8.7 8.1 6.4

Thomomys bottae cultellus, Fishers Peak

♀ 129285[1] sad. 214 64 27 37.2 13.0 .... 19.0 15.3 7.7 7.6 6.5

Thomomys bottae rubidus, holotype and topotypes

♀ 72952[4] 233 80 28 40.6 14.2 25.1 20.8 16.7 8.8 7.5 6.9

♀ 72954[4] 225 80 28 40.3 14.2 24.6 20.6 16.6 9.2 7.2 6.9

♂ 3 av. 261 89 31 44.7 15.7 27.8 22.6 18.6 10.1 7.4 6.9

Max. 270 94 32 45.1 15.9 28.1 22.7 18.8 10.4 7.6 7.0

Min. 255 85 30 44.2 15.5 27.5 22.5 18.5 9.8 7.2 6.8