Hipparionini

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.

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.

thumb|left|H. afarense mandible

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

Hipparionini is an extinct tribe of three-toed equids in the subfamily Equinae. They had body forms similar to modern equines, with high-crowned teeth. They first appeared in North America during the Early Miocene around 17 million years ago, before migrating into the Old World around 11.4-11.0 million years ago. The youngest species date to the end of the early Early Pleistocene, becoming extinct following the arrival of modern equines of the genus Equus to the Old World.

Proboscidipparion is an extinct genus of hipparionine equine. It is named after its unusual retracted nasal region of the skull, which may have supported a proboscis. Fossils have been found throughout Eurasia, from England (Red Crag) to China. The oldest specimens are known from Asia, dating to the Early Pliocene, around 5.3-5 million years ago. The genus was one of the last surviving hipparionines, with the youngest specimen dating to the end of the Early Pleistocene, around 1 million years ago.

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.

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.

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.