''Haplohippus'' is an extinct genus of the modern

horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million y ...

family

Equidae Equidae (sometimes known as the horse family) is the taxonomic family of horses and related animals, including the extant horses, asses, and zebras, and many other species known only from fossils. All extant species are in the genus '' Equus'', ...

, that lived in the

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

, from 42 to 38 million years ago. Fossil remains of ''Haplohippus'' have been found in the

Clarno Formation Clarno may refer to: Locations * Clarno, Oregon * Clarno, Wisconsin ** Clarno (community), Wisconsin *Clarno Township, Lake County, South Dakota Lake County is a county in the U.S. state of South Dakota. As of the 2020 United States Census, t ...

, part of the

John Day Fossil Beds National Monument John Day Fossil Beds National Monument is a U.S. national monument in Wheeler and Grant counties in east-central Oregon. Located within the John Day River basin and managed by the National Park Service, the park is known for its well-preserved l ...

of the Northwestern United States. While ''Haplohippus'' is quite similar to ''

Orohippus ''Orohippus'' (from the Greek , 'mountain' and , 'horse') is an extinct equid that lived in the Eocene (about 50 million years ago). It is believed to have evolved from equids such as ''Eohippus'', as the earliest evidence for ''Orohippus' ...

'', it is considered more primitive in character than ''

Epihippus ''Epihippus'' is an extinct genus of the modern horse family Equidae that lived in the Eocene, from 46 to 38 million years ago. ''Epihippus'' is believed to have evolved from ''Orohippus'', which continued the evolutionary trend of increasing ...

''.MacFadden, Bruce J. 1976 "Cladistic Analysis of Primitive Equids, with Notes on Other Perissodactyls" ''Systematic Zoology'' 25(1):1-14

References

Eocene horses Eocene odd-toed ungulates Eocene mammals of North America Paleogene geology of Oregon Prehistoric placental genera John Day Fossil Beds National Monument Extinct mammals of North America Eocene genus extinctions Eocene extinctions Clarno Formation {{paleo-oddtoedungulate-stub