''Parahippus leonensis'' is an extinct proto-

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 ...

of the 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 was endemic to

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

during the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

from 23.030 to 16.3 Ma living for approximately . ''Parahippus leonensis'' was named for Leon or more specifically

Leon County, Florida Leon County is a county in the Panhandle of the U.S. state of Florida. It was named after the Spanish explorer Juan Ponce de León. As of the 2020 census, the population was 292,198. The county seat is Tallahassee, which is also the state cap ...

Taxonomy

''Parahippus leonensis'' was named by Sellards (1916). Its type specimen is FGS 5084. Its type locality is

Griscom Plantation site Notable people with the surname Griscom include: * Betsy Ross, probably apocryphal designer of the American flag, born Elizabeth Phoebe Griscom * Clement Griscom, American shipping magnate, father of Frances C. Griscom * Deborah Griscom Passmore, A ...

, which is in a Miocene marine

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

in the

Torreya Formation The Torreya Formation is a Miocene geologic formation with an outcrop in North Florida. It is within the Hawthorn Group. Age Period: Neogene Epoch: Early Miocene Faunal stage: Aquitanian through early Messinian ~19–15.3 mya, calculates to a ...

of Florida. It was recombined as '' Hippodon leonensis'' by Quinn (1955); it was considered a ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

'' by Macdonald (1992).

Origin

''Parahippus leonensis'' was the next step in evolution after ''

Miohippus ''Miohippus'' (meaning "small horse") was a genus of prehistoric horse existing longer than most Equidae. ''Miohippus'' lived in what is now North America from 32 to 25 million years ago, during the late Eocene to late Oligocene. ''Miohippus'' w ...

''. ''

Parahippus ''Parahippus'' ("near to horse"), is an extinct equid, a relative of modern horses, Donkey, asses and zebras. It lived from 24 to 17 million years ago, during the Miocene epoch. It was very similar to ''Miohippus'', but slightly larger, at around ...

'' means "side horse" and has been called the evolutionary link between the older

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

-dwelling horses and modern

plain In geography, a plain is a flat expanse of land that generally does not change much in elevation, and is primarily treeless. Plains occur as lowlands along valleys or at the base of mountains, as coastal plains, and as plateaus or uplands ...

s-dwelling grazers. It is believed to be a close relative to the group from which modern horses evolved. Side may refer to side branches on the posterior crest of the upper molars which separated ''Parahippus'' from ''

Anchitherium ''Anchitherium'' (meaning ''near beast'') was a fossil horse with a three- toed hoof. ''Anchitherium'' was a browsing (leaf eating) horse that originated in the early Miocene of North America and subsequently dispersed to Europe and Asia,(in C ...

''. This genus of horses had a long head with eyes situated back from the middle of the skull. It had three toes, like other primitive horses, however ''Parahippus leonensis'' had smaller side toes. It was a common species from the

Great Plains The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, an ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

. ''Parahippus leonensis'' weighed in at about 72.5 kg (160 pounds).Fossil Horses, Florida Museum of Natural History ''Parahippus leonensis'' was very likely the prey of ''

Amphicyon ''Amphicyon'' ("ambiguous dog") is an extinct genus of large carnivorous bone-crushing mammals, popularly known as bear dogs, of the family Amphicyonidae, subfamily Amphicyoninae, from the Burdigalian Epoch until the late Pliocene, with the creat ...

'' or bear-dog, and dog-like ''

Temnocyon ''Temnocyon'' is an extinct genus of bear-dogs endemic to North America. It lived from the Oligocene to Early Miocene approximately 30.8—20.4 mya, existing for about . The first fossils are recorded in North America at Logan Butte in the Joh ...

''.

References

Miocene odd-toed ungulates Burdigalian extinctions Miocene mammals of North America Miocene horses Aquitanian species first appearances {{paleo-oddtoedungulate-stub