New discovery of early Pleistocene orangutan fossils from Chongzuo in southern China.

28 isolated orangutan fossil teeth are reported in this paper, which are newly discovered from Sanhe Cave in Chongzuo Ecological Park of Guangxi in southern China. The geological age is early Pleistocene, approximately 1.2 Ma ago based on the associated mammal fauna and paleomagnetic dating. The tooth crown sizes are within the variation of extant orangutan and subfossil orangutan from Indonesia. However, by comparing the distribution complex of samples, the crown sizes of fossil orangutan from Sanhe Cave move upward from the mean value of extant orangutan and Holocene subfossil orangutan. The distinct difference of tooth morphological between the fossil and subfossil and extant orangutan is difficult to define currently, although the occlusal wrinkles of postcanine teeth of fossil orangutan from Sanhe Cave are less and coarser somehow than that of extant orangutan. We suggest the fossil orangutan teeth of Early Pleistocene from Sanhe Cave are classified as the subspecies Pongo pygmaeus weidenreichi temporarily, and the evolution and taxonomy of fossil orangutan-like hominoids in southern China need to be interpreted with more evidence. [ABSTRACT FROM AUTHOR]