Moropus

Moropus (meaning "slow foot") is an extinct genus of large perissodactyl mammal in the chalicothere family. They were endemic to North America during the Miocene from ~20.4–13.6 Mya, existing for approximately 6.8 million years. Moropus belonged to the schizotheriine subfamily of chalicotheres, and has the best fossil record of any member of this group; numbers of individuals, including complete skeletons, have been found. The type species of Moropus, M. distans, was named by Othniel Charles Marsh in 1877, alongside two other species, M. elatus and M. senex. Three more species have been named since. Others have been named, but have either been invalidated for one reason or another, or reclassified to other genera.

Among the largest chalicotheres, some specimens of Moropus stood 2.4 m (8 ft) at the shoulder. One specimen had an estimated body mass of 1,179 kg (2,599 lb). Its dental anatomy was similar to ruminants, suggesting a similar method of cropping vegetation. Retracted nasal bones suggest a long upper lip, and a wide gap between the lower incisors and cheek teeth, called a diastema, would provide room for a long tongue to extend from the mouth at an angle. Together, the upper lip and tongue may have been used to pull down vegetation. Though not as adept at bipedalism as the related Chalicotherium, it may nonetheless have reared up on two legs to browse on vegetation, using its claws to hook into the bark of a tree or using them to pull down leaves that would otherwise have been unreachable. Moropus may have been sexually dimorphic, with the males being larger than the females.