| Sifrhippus Temporal range: Early Eocene |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Perissodactyla |
| Family: | Equidae |
| Genus: | †Sifrhippus Froehlich, 2002 |
| Binomial name | |
| †Sifrhippus sandrae (Gingerich, 1989) |
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| Synonyms | |
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Sifrhippus is an extinct, monotypic genus of equid containing the sole species Sifrhippus sandrae. Sifrhippus is the oldest equid known from North America, and its fossils come from the earliest Eocene of the Bighorn Basin, Wyoming.[1][2]
Sifrhippus was a very small equid the size of a house cat.[1] Sifrhippus sandrae is referred to in earlier literature as Hyracotherium sandrae, but Froehlich, arguing that the traditional genus Hyracotherium was not monophyletic, reassigned many of its species to other genera and re-using the old name "Eohippus" for one. Froehlich give H. sandrae the new generic name Sifrhippus, derived from the Arabic sifr, "zero", and Greek hippos, "horse".[2]