| Otospermophilus Brandt, 1844 |
| Otospermophilus adocetus Merriam, 1903 |
| Otospermophilus annulatus Audubon & Bachman, 1842 |
| Otospermophilus annulatus subsp. goldmani (Merriam, 1902) |
| Otospermophilus atricapillus (W. E. Bryant, 1889) |
| Otospermophilus beecheyi (Richardson, 1829) |
| Otospermophilus beecheyi subsp. atricapillus (W. E. Bryant, 1889) |
| Otospermophilus beecheyi subsp. nudipes (Huey, 1931) |
| Otospermophilus beecheyi subsp. rupinarum (Huey, 1931) |
| Otospermophilus grammurus (Say, 1823) |
| Otospermophilus grammurus subsp. atricapillus (Bryant, 1889) |
| Otospermophilus grammurus subsp. rupestris (J. A. Allen, 1903) |
| Otospermophilus variegatus (Erxleben, 1777) |
| Otospermophilus variegatus subsp. couchii (Baird, 1855) |
| Otospermophilus variegatus subsp. grammurus (Say, 1823) |
| Otospermophilus variegatus subsp. juglans Miller, 1924 |
| Otospermophilus variegatus subsp. rupestris (J. A. Allen, 1903) |
| Otospermophilus variegatus subsp. variegatus (Erxleben, 1777) |
| Pteromyini Brandt, 1855 |
| Sciuridae Fischer von Waldheim, 1817 |