Abstract: Past research by the senior author ( Turner) indicates that Upper Cave Zhoukoudian specimens ( Nos. 101, 102, 103) display a distinct dental morphological trait pattern known as Sinodonty, a dental pattern shared with other north Asian and north Asian-derived populations. Recently , the Sinodont designation was questioned, primarily on the grounds that the dental traits could not be assessed reliably from the available casts. The same three casts were again scored for trait data, this time by three observers o f varying levels of experience, and in independent tests. Comparative observations support the reliability of the original scores on cast material, even when the most conservative scoring methods were utilized. The results agree with bioarchaeological evidence that the three specimens should be considered members of the same biological population. In addition, data lend support for proto-Sundadonty as the dental pattern ancestral to the Upper Cave Zhoukoudian Sinodont pattern.

Key words: Zhoukoudian Upper Cave, Sinodont dentition, Modern human origins