| Guide to subspecies: | 12. T. b. aureiventris | 24. T. b. lenis |
|---|---|---|
| 1. T. t. gracilis | 13. T. b. robustus | 25. T. b. levidensis |
| 2. T. t. wasatchensis | 14. T. b. minimus | 26. T. b. osgoodi |
| 3. T. t. oquirrhensis | 15. T. b. nesophilus | 27. T. b. howelli |
| 4. T. t. uinta | 16. T. b. stansburyi | 28. T. b. wahwahensis |
| 5. T. t. pygmaeus | 17. T. b. albicaudatus | 29. T. b. dissimilis |
| 6. T. t. ravus | 18. T. b. bonnevillei | 30. T. b. aureus |
| 7. T. t. ocius | 19. T. b. centralis | 31. T. b. birdseyei |
| 8. T. t. moorei | 20. T. b. sevieri | 32. T. b. virgineus |
| 9. T. t. fossor | 21. T. b. convexus | 33. T. b. planirostris |
| 10. T. t. parowanensis | 22. T. b. tivius | 34. T. b. absonus |
| 11. T. t. levis | 23. T. b. contractus | 35. T. b. alexandrae |
Genus Thomomys Wied
All pocket gophers of Utah belong to the genus Thomomys. There are only two species within the state, Thomomys bottae with twenty-four subspecies and Thomomys talpoides with eleven subspecies.
Due to marked mutational capacities and ready response to environmental pressures and sedentary habits, pocket gophers differentiate readily into numerous subspecies. It is well known that Utah by its highly varied topography and climate possesses widely different types of habitats. The aforementioned plasticity of these animals and possibly the fact that both species are at the extreme limits of their ranges in Utah account for the numerous forms found within the state.
The genus may be characterized as follows: Highly specialized fossorial rodents, with heavy, thick bodies; all four legs of approximately equal length, but front legs more muscular for digging, and feet provided with long claws; external fur-lined cheek pouches; small eyes, short ears and tail; upper incisors long and projecting external to lips. Skull: Stout and flattened; zygomatic arches well developed and usually widely spreading; all teeth with permanent pulp cavities; incisors superficially smooth, but fine median groove present on anterior face of each upper incisor; dental formula, i. 1/1, c. 0/0, p. 1/1, m. 3/3; external auditory canal long; stapedial artery small and enclosed within an osseous canal.