Chalicotheriidae

Chalicotheres are an unusual group of extinct fossil perissodactyls that, despite a dentition suited for a herbivorous diet, had claws on their digits instead of hooves. The group first appeared in the Eocene, reached its highest diversity in the Miocene, and went extinct in the Pleistocene. Chalicotheres seem to have undergone much of their diversification in Asia but are also found in Europe, Africa, and North America. Oligocene and later chalicotheres belong to the family Chalicotheriidae, which includes two subfamilies, the Chalicotheriinae and Schizotheriinae. Chalicothere fossils are rare and in Africa are known mostly from fragmentary remains. Virtually all known African members of the Chalicotheriinae are restricted to the early Miocene and belong to a single, relatively basal species, Butleria rusingensis. Later African chalicotheres belong to the Schizotheriinae and have been referred to three species: Ancylotherium hennigi, Ancylotherium cheboitense, and “Chemositia” tugenensis. Ancylotherium hennigi was the last surviving member of the Schizotheriinae worldwide. This chapter describes the systematic paleontology of Chalicotheriidae.