Orohippus

{{Short description|Extinct genus of mammals}}

{{More citations needed|date=July 2007}}

{{Automatic taxobox

| fossil_range = early to middle EoceneMacFadden, 1998, p.554

| image = Orohippus pumilus Marsh, 1871 2.jpg

| image_caption = Skeleton of Orohippus pumillus at the Smithsonian Museum of Natural History.

| taxon = Orohippus

| authority = Marsh, 1872

| type_species = †Orohippus pumillus

| subdivision_ranks = Species

| subdivision_ref = MacFadden, 1998, p.543

| subdivision = * †O. agilis

• †O. major
• †O. progressus
• †O. proteros
• †O. pumillus
• †O. sylvaticus

}}

Orohippus (from the Greek {{lang|grc|ὄρος}} {{Transliteration|grc|óros}}, 'mountain' and {{lang|grc|ἵππος}} {{Transliteration|grc|híppos}}, 'horse'{{cite web|url=https://research.amnh.org/paleontology/perissodactyl/concepts/glossary|archive-url=https://web.archive.org/web/20211120123130/https://research.amnh.org/paleontology/perissodactyl/concepts/glossary|archive-date=20 November 2021|title=Glossary. American Museum of Natural History}}) is an extinct equid that lived in the Eocene (about 50 million years ago). Its fossils have been unearthed in Oregon, Colorado, Utah, and Wyoming.{{Cite journal |last=Korth |first=William W. |last2=Evander |first2=Robert L. |date=1982 |title=A New Species of Orohippus (Perissodactyla, Equidae) from the Early Eocene of Wyoming |url=https://www.jstor.org/stable/4522893 |journal=Journal of Vertebrate Paleontology |volume=2 |issue=2 |pages=167–171 |issn=0272-4634}}{{Cite journal |last=Nelson |first=Michael E. |date=1973-04-01 |title=Age and stratigraphic relations of the Fowkes Formation, Eocene, of southwestern Wyoming and northeastern Utah |url=https://pubs.geoscienceworld.org/uwyo/rmg/article-abstract/12/1/27/87694/Age-and-stratigraphic-relations-of-the-Fowkes?redirectedFrom=PDF |journal=Rocky Mountain Geology |volume=12 |issue=1 |pages=27–31 |issn=1555-7332}}{{Citation |last=Stucky |first=Richard K. |title=Magnetic stratigraphy, sedimentology, and mammalian faunas of the early Uintan Washakie Formation, Sand Wash Basin, northwestern Colorado |date=1996-06-13 |work=The Terrestrial Eocene-Oligocene Transition in North America |pages=40–51 |url=https://doi.org/10.1017/cbo9780511665431.004 |access-date=2025-03-09 |publisher=Cambridge University Press |last2=Prothero |first2=Donald R. |last3=Lohr |first3=Walter G. |last4=Snyder |first4=Jennifer R.}}{{Cite journal |last=Farr |first=Marcus S. |date=1896 |title=Notes on the Osteology of the White River Horses |url=https://www.jstor.org/stable/983260 |journal=Proceedings of the American Philosophical Society |volume=35 |issue=151 |pages=147–175 |issn=0003-049X}}{{Cite book |last=Turnbull |first=William D. |url=https://doi.org/10.5962/bhl.title.3567 |title=The mammalian faunas of the Washakie Formation, Eocene age, of southern Wyoming |date=2002 |publisher=Field Museum of Natural History |location=Chicago, Ill}}{{Citation |last=Marsh |first=O. C. |title=“Fossil Horses in America,” American Naturalist (1874) |date=2012-03-01 |work=An Anthology of Nineteenth-Century American Science Writing |pages=177–183 |url=https://doi.org/10.7135/upo9780857286512.032 |access-date=2025-03-09 |publisher=Anthem Press}}{{Cite journal |last=Marsh |first=O. C. |date=1874-03-01 |title=Notice of new equine mammals from the Tertiary formation |url=https://doi.org/10.2475/ajs.s3-7.39.247 |journal=American Journal of Science |volume=s3-7 |issue=39 |pages=247–258 |doi=10.2475/ajs.s3-7.39.247 |issn=0002-9599}}