| Protorohippus Temporal range: Eocene (Wasatchian) | |
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| Fossil from the Green River Formation | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Perissodactyla |
| Family: | Equidae |
| Genus: | † Protorohippus Wortman, 1896 |
| Type species | |
| Protorohippus venticolum (Cope, 1881) | |
| Species | |
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| Synonyms | |
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Protorohippus (Latin: "before" (pro), + Greek: "mountain" (oros), "horse" (hippos) [1] ) is an extinct genus of equid that lived in the Eocene of North America. [2]
Based on oxygen and carbon isotope analysis of the teeth of P. montanum, the species is believed to have had two distinct birth seasons per year, a result of the diminished seasonality during the Early Eocene. It is possible that this phenomenon held for other early equids as well. [3]