Dispersal patterns of Eurasian hominoids: implications from Turkey

A key to understanding the complex pattern of hominoid dispersals, origins, and extinction is the fossil evidence from Turkey. Miocene localities in Turkey are known to contain taxa from across Eurasia and Africa, and even North America. Three or four separate hominoid clades are identified in Anatolia, more than in any other place except Kenya. Each of these clades has its closest affinities with hominoids from different continents. Hominoids disperse into Eurasia at the beginning of MN 5, ahead of the Langhian transgression, probably as a result of the key adaptation of thick occlusal enamel and robust jaws and teeth, first observed in Afropithecus and Heliopithecus from Kenya and Saudi Arabia. Subtropical and mainly forested conditions encourage rapid dispersal and diversification of hominoids in Eurasia, while trends toward more open conditions in sub-Saharan Africa lead to the reduction in diversity and eventual extinction of African pre-modern hominoids. Toward the end of the Vallesian, Eurasian hominoids undergo a series of extinction events that begin in the northwestern end of their range (Dryopithecus from Western and Central Europe) and end near the end of the Miocene in Southern China (Lufeng and Hudieliangzi, Yunnan Province). Of the last surviving Eurasian hominoids, the Yunnan taxa appear to have affinities to Pongo while the latest forms from Europe and western Asia are most closely related to the African apes and humans. Localities in Turkey document the earliest evidence of hominoids in Eurasia, the spread of hominoids across Eurasia, and, perhaps, the return to Africa in the Turolian of the common ancestor of the African apes and humans.