Temporal range: late Miocene
|Protohippus simus skeleton|
Protohippus is an extinct three-toed genus of horse. It was roughly the size of a modern donkey. Fossil evidence suggests that it lived during the Late Miocene and Early Pliocene, from about 14 Ma to 6 Ma.
Analysis of Protohippus' skull and teeth suggests that it is most closely related to the genus Calippus.
- P. vetus
- P. perditus
- P. supremus (also P. simus)
- P. gidleyi
- MacFadden, Bruce J.; Dobie, James L. (1998). "Late Miocene Three-Toed Horse Protohippus (Mammalia, Equidae) from Southern Alabama". Journal of Paleontology 72 (1): 149–152. JSTOR 1306685.