New 400–320 ka Gigantopithecus blacki remains from Hejiang Cave, Chongzuo City, Guangxi, South China

Gigantopithecus blacki is a typical member of the Stegodon–Ailuropoda faunal complex (sensu lato) that inhabited southern China or, more broadly, mainland Southeast Asia during the Early and Middle Pleistocene. Current evidence indicates that the giant ape became extinct during the Middle Pleistocene. Recently, new remains of G blacki and associated mammalian fossils have been unearthed from a karst cave site, Hejiang Cave, in Chongzuo City, Guangxi, South China. The age of the Gigantopithecus-bearing depositional unit is estimated to be 400–320 ka using 230Th–234U disequilibrium U-series dating of flowstone samples bracketing the deposits. These finds document the latest occurrence of Gigantopithecus and provide potential insights regarding its extinction. Comparisons of dental dimensions between the Hejiang G. blacki remains, more than four hundred isolated teeth from Early Pleistocene localities, and over ninety isolated teeth from local drugstores show that the Hejiang teeth are slightly larger in their buccolingual dimensions. In addition, the crowns of the three unerupted upper premolars differ from those of all of the other Gigantopithecus material in having more complex crenulations. The differences in dental dimensions and morphology are possibly reflective of dietary responses to environmental changes that eventually led to the extinction of Gigantopithecus.