English: Acritohippus isonesus (Cope, 1889) - fossil horse skeleton from the Miocene of Nebraska, USA. (CM 9080, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA)

This species is also known as Merychippus isonesus.

From museum signage: "With Merychippus, the horse begins to look more like its modern-day counterpart. This creature stands at the midpoint of horse evolution.

The greatest evolutionary adaptation comes right from the horse’s mouth. Merychippus was the earliest horse to adapt its diet to grass. Its higher crowned teeth and deep jaws were adaptations for grazing the tough prairie grass.

Although it still had three toed feet rather than hooves, Merychippus was quite the runner and adept at dodging the predators of the day. "

Classification: Animalia, Chordata, Vertebrata, Mammalia, Perissodactyla, Equidae

Stratigraphy: Sheep Creek Formation, Middle Miocene

Locality: Sheep Creek, northwestern Nebraska, USA