Diadiaphorus

Diadiaphorus is an extinct genus of litoptern mammal from the Miocene of Argentina (Ituzaingó, Pinturas, Chiquimil and Santa Cruz Formations) and Bolivia (Nazareno Formation), South America.
Description.
"Diadiaphorus" closely resembled a horse, but was only around in body length with a weight , similar to a modern sheep. It had three toes, only one of which touched the ground. This toe had a large hoof; the two outer toes were rudimentary, much like those of early horses such as "Merychippus". Unlike horses, however, "Diadiaphorus" lacked fused limb bones. Its skull was short and had a relatively large brain cavity. Judging from its low molars, "Diadiaphorus" ate soft vegetation, such as leaves.