New Fossil Suid Specimens from the Terminal Miocene Hominoid Locality of Shuitangba, Zhaotong, Yunnan Province, China

Fossil suid specimens recovered from the latest Miocene site of Shuitangba, Zhaotong Basin, Yunnan Province, provide new information on the classification and relationship of Chinese Miocene Suinae. Most of the recovered specimens are referred to a relatively advanced and large species of Suinae, Propotamochoerus hyotherioides, based on dental dimensions and morphology. Detailed morphological comparisons were made between the Shuitangba Pr. hyotherioides and other Asian Miocene suines. From these comparisons, we suggest that Pr. hyotherioides from Shuitangba and northern China may be relatively derived compared to the specimens from Lufeng and Yuanmou, southern China and that Pr. hyotherioides and Pr. wui represent separate branches of the genus in China. Furthermore, Microstonyx differs from Pr. hyotherioides in p4/P4 and m3/M3 characters. Molarochoerus is suggested to represent a relatively derived taxon due to the uniquely molarized upper and lower fourth premolars. Miochoerus youngi is suggested to have a closer relationship to Sus and Microstonyx than to Propotamochoerus due to its small size and p4 morphology. Hippopotamodon ultimus, Potamochoerus chinhsienense, Dicoryphochoerus medius, and D. binxianensis exhibit complex morphologies that variously resemble Propotamochoerus, Microstonyx, and Sus and are suggested to be possible transitional forms between Propotamochoerus, Microstonyx, and Sus. However, the resolution of their classification requires further analysis when more material is recovered.