Fossil Suidae (Artiodactyla, Mammalia) from Aves Cave I and nearby sites in Bolt’s Farm Palaeokarst System, South Africa

Excavations carried out since 2011 at Bolt’s Farm Palaeokarst System, South Africa, have led to the recovery of interesting remains of suids, notably from Aves Cave I. The taxa present are Potamochoeroides hypsodon and Notochoerus capensis , the same as those that occur at Makapansgat. The new Notochoerus material, which includes an upper third molar and a lower fourth premolar, strengthens the conclusion that this genus is a suine and not a tetraconodont as thought for the past half century. Potamochoeroides has thickened mandibular rami indicating that it descended from the genus Dasychoerus that dispersed into Africa from Eurasia about 5 million years ago. Other karst deposits at Bolt’s Farm have yielded a younger suid fauna comprising Metridiochoerus andrewsi and Phacochoerus modestus , indicating that the Bolt’s Farm Karst System was active for a considerable period of time (ca 4.5 Ma - 1.8 Ma). The fact that all the suid taxa from Bolt’s Farm are hypsodont indicates that the palaeoenvironment contained abundant grass.