Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: ParaHoxozoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Cladus: Olfactores
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Cladus: Synapsida
Cladus: Eupelycosauria
Cladus: Metopophora
Cladus: Haptodontiformes
Cladus: Sphenacomorpha
Cladus: Sphenacodontia
Cladus: Therapsida
Cladus: Theriodontia
Cladus: Eutheriodontia
Cladus: Cynodontia
Cladus: Epicynodontia
Cladus: Eucynodontia
Cladus: Probainognathia
Cladus: Prozostrodontia
Cladus: Mammaliamorpha
Cladus: Mammaliaformes
Classis: Mammalia
Cladus: Theriimorpha
Cladus: Theriiformes
Cladus: Trechnotheria
Cladus: Cladotheria
Cladus: Prototribosphenida
Cladus: Zatheria
Cladus: Tribosphenida
Cladus: Boreosphenida
Subclassis: Theria
Cladus: Eutheria
Infraclassis: Placentalia
Magnordo: Boreoeutheria
Superordo: Laurasiatheria
Cladus: Scrotifera
Grandordo: Ferungulata
Mirordo: Euungulata
Ordo: Perissodactyla
Superfamilia: Equoidea
Familia: Equidae
Subfamilia: †Hyracotheriinae
Genus: Orohippus
Species: O. cinctus – O. agilis – O. major – O. procyoninus – O. progressus – O. proteros – O. pumilus – O. sylvaticus
Name
Orohippus Marsh, 1872
References
Orohippus. Fossilworks. Accessed on 24 November 2015.
Vernacular names
català: Orohip
English: Orohippus
فارسی: کوهاسب
עברית: אורוהיפוס
日本語: オロヒップス
한국어: 오로히푸스
русский: Орогиппусы
Orohippus (from the Greek ὄρος óros, 'mountain' and ἵππος híppos, 'horse'[3]) is an extinct equid that lived in the Eocene (about 50 million years ago).
Description
O. pumillus, AMNH
It is believed to have evolved from equids such as Eohippus, as the earliest evidence for Orohippus appears about 2 million years after the first appearance of Eohippus. The anatomical differences between the two are slight: they were the same size, but Orohippus had a slimmer body, a more elongated head, slimmer forelimbs and longer hind legs, all of which are characteristics of a good jumper. Its teeth were brachydont in height, but the development of flattened surfaces and shearing lophs on their molars suggests they were more a browser than a frugivore.[4] The outer toes of Eohippus are no longer present in Orohippus, hence on each forelimb there were four fingers (toes) and on each hind leg three toes.
Species of Orohippus has also been referred to Protorohippus.
See also
Evolution of the horse
Horse
Notes
MacFadden, 1998, p.554
MacFadden, 1998, p.543
"Glossary. American Museum of Natural History". Archived from the original on 20 November 2021.
Kitts, D. B. 1957. A Revision of the Genus Orohippus (Perissodactyla, Equidae). American Museum Novelties, 1864:1–40.
References
MacFadden, B.J., 1998. Equidae. pp. 537–559 in C.M. Janis, K.M. Scott, and L.L. Jacobs (eds.) Evolution of Tertiary Mammals of North America Cambridge University Press, Cambridge.
Orohippus, Index Fossils and the Tertiary
The Evolution of the Horse
National Center for Science Education
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