Miocene horses

Hipparion is an extinct genus of three-toed, medium-sized equine belonging to the extinct tribe Hipparionini, which lived about 10-5 million years ago. While the genus formerly included most hipparionines, the genus is now more narrowly defined as hipparionines from Eurasia spanning the Late Miocene. Hipparion was a mixed-feeder who ate mostly grass, and lived in the savannah biome. Hipparion evolved from Cormohipparion, and went extinct due to environmental changes like cooling climates and decreasing atmospheric carbon dioxide levels.

Merychippus is an extinct proto-horse of the family Equidae that was endemic to North America during the Miocene, 15.97–5.33 million years ago. It had three toes on each foot and is the first horse known to have grazed.

Pliohippus (from Ancient Greek πλείων (pleíon), meaning "more", and ἵππος (híppos), meaning "horse") is an extinct genus of Equidae, the horse family. Pliohippus arose in the middle Miocene, around 15 million years ago. The long and slim limbs of Pliohippus reveal a quick-footed steppe animal. While some specimens have one toe per leg, others have three (the main toe and two non-functional side toes).

Parahippus ("near to horse"), is an extinct equid, a relative of modern horses, 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 tall, at the withers. Their fossils have been found in North America, primarily in the Great Plains region and Florida.

Anchitherium (meaning near beast) is a genus of extinct equid with a three-toed hoof. thumb|left|Mandibles Anchitherium was a browsing (leaf eating) horse that originated in the early Miocene of North America, being found as far south as Panama, and subsequently dispersed to Europe and Asia, where it gave rise to the larger bodied genus Sinohippus. It was around high at the shoulder, and probably represented a side-branch of horse evolution that left no modern descendants.

Equinae is a subfamily of the family Equidae, known from the Hemingfordian stage of the Early Miocene (16 million years ago) onwards. They originated in North America, before dispersing to every continent except Australia and Antarctica. They are thought to be a monophyletic grouping. Members of the subfamily are referred to as equines; the only extant equines are the horses, asses, and zebras of the genus Equus, with two other genera Haringtonhippus and Hippidion becoming extinct at the beginning of the Holocene, around 11–12,000 years ago.

Megahippus is an extinct genus of large Anchitheriine horses found throughout the southern portion of the United States during the middle Miocene. The animal represents one of the latest low-crowned horses, overlapping in time with more derived high-crowned horses.

Hypohippus (Greek: "under" (hypos), "horse" (hippos)) is an extinct genus of three-toed horse, which lived 17–11 million years ago. It was the largest anchitherine equid about the size of a modern domestic horse, at and long. It was a long-necked, high-shouldered browser with sub-hypsodont, lophodont (rhino-like) dentition, that fed on the tough vegetation of forest understory and shrubs. Its deep preorbital fossae and retraction of the nasal notch hint at the presence of a long, muscular and prehensile upper lip that would aid during selective browsing. Overall its ecology would have been mor

Dinohippus (from Ancient Greek δεινός (deinós), meaning "terrible", and ἵππος (híppos), meaning "horse") is an extinct equid which was endemic to North America from the late Hemphillian stage of the Miocene through the Zanclean stage of the Pliocene (10.3—3.6 mya) and in existence for approximately . Fossils are widespread throughout North America, being found at more than 30 sites from Florida to Alberta and from Mexico all the way down to Panama (Alajuela Formation). The majority of fossils of Dinohippus have been unearthed in the Western United States in Nevada, New Mexico, Utah, and Califo

Equini is the only living tribe of the subfamily Equinae, which has lived worldwide (except Australia) since the Hemingfordian stage of the Middle Miocene (16–0 mya). It is considered to be a monophyletic clade.

left|thumb|Life restoration Archaeohippus (Greek: "ancient" (archaios), "horse" (hippos)) is an extinct three-toed member of the family Equidae known from fossils of early Oligocene to middle Miocene age. The genus is noted for several distinct skeletal features. The skull possesses deeply pocketed fossa in a notably long preorbital region. The genus is considered an example of phyletic dwarfism with adults estimated at being on average 20 kilograms in weight. This is in contrast to the most common equid of the period, Miohippus. Characters of the teeth show a mix of both primitive and advance

thumb|left|H. afarense mandible

Nannippus is an extinct genus of three-toed horse endemic to North America during the Miocene through Pleistocene, about 13.3—1.8 million years ago (Mya), living around 11.5 million years. This ancient species of three-toed horse grew up to and weighed between 165 pounds (75 kilograms) to 199 pounds (90 kilograms), which was around the same size as a domestic sheep.

Hippotherium is an extinct genus of horse that lived during the Miocene through Pliocene ~13.65—6.7 Mya, existing for .

Astrohippus is an extinct member of the Equidae tribe Equini, the same tribe that contains the only living equid genus, Equus. Fossil remains have been found in the central United States, Florida, and the Mexican states of Chihuahua, Jalisco, and Guanajuato. The fossils date in time from the oldest dating from the Barstovian in the Miocene to the youngest dating in the Hemphillian faunal stage of the early Pliocene.

Protohippus is an extinct three-toed genus of horse. It was roughly the size of a modern donkey. Fossil evidence suggests that it lived during the Late Miocene (Clarendonian to Hemphillian), from about 13.6 Ma to 5.3 Ma.

thumb|left|Restoration by Charles R. Knight upright|thumb|left|Mare and foal at Ashfall Fossil Beds Neohipparion (Greek: "new" (neos), "pony" (hipparion)) is an extinct genus of equid, from the Neogene (Miocene to Pliocene) of North America and Central America.

left|thumb|Life restoration Kalobatippus ('stilt walking horse') is a genus of anchitheriinae equid. It gets its name from the elongated bones between the ankle/wrist and the toes. Kalobatippus ate leaves and was characterized by unusually long legs. It lived 24 to 19 million years ago. Estimated body mass for Kalobatippus is .

Desmatippus is an extinct, three-toed, browsing member of the Equidae. It lived in what is now North America during the Miocene period (about 23 mya to 5 mya). Desmatippus was 60 cm in height and 20 kg in weight.

Cormohipparion (Greek: "noble" (cormo), "pony" (hipparion) is an extinct genus of horse belonging to the tribe Hipparionini that lived in North America and Eurasia during the Late Miocene to Pliocene (Hemphillian to Blancan in the NALMA classification). They grew up to long.

left|thumb|Holotype of S. sampelayoi thumb|left|Fragment of a S. sampelayoi maxilla

genus of mammals

Pseudhipparion is an extinct genus of three-toed horse endemic to North America during the early to late Miocene. They were herding animals whose diet consisted of C3 plants, implying that they were grazers. Fossils of Pseudhipparion have been found in Georgia, Florida, Oregon, Montana, Kansas, Texas, Nebraska, and South Dakota indicate that it was a lightweight horse, weighing up to 90 pounds (40 kilograms). In 2005, fossils were unearthed in Oklahoma. Seven species of Pseudhipparion are known from the fossil record, which were very small, following the trend of Bergmann's rule.