Condylarthra

(cohort Ferungulata, superorder Protoungulata)

An extinct order comprising seven families of primitive ungulates, including some that resemble the original eutherian stock so closely that their classification has presented many difficulties; some authors break the order into several different groups, assigned to other orders. Condylarths appear to be transitional between insectivores and true ungulates. They ranged from the late Cretaceous to the latter part of the Miocene and were a major part of the Palaeocene fauna. Some forms possessed claws and may have been arboreal (Hyopsodontidae), others became highly specialized, but the development of hoofs and ungulate dentition can be traced to families in the order.