Comparisons of tooth size and morphology between the late Miocene hominoids from Lufeng and Yuanmou, China, and their implications

The relationship between the Yuanmou hominoid and the Lufeng hominoid (Lufengpithecus lufengensis), both from Yunnan Province, China, and among the most abundantly represented fossil hominoid of Eurasia, has been the subject of much debate. In the past 10 years, comparative studies of cranial and dental morphology of the Lufeng and Yuanmou hominoids indicate that the two hominoids resemble each other more than either of them resemble any other Miocene hominoid. In this paper, we summarize the dental differences seen between the Yuanmou and Lufeng hominoids, and discuss their implications. Our results show that the Lufeng hominoid has relatively smaller front teeth, smaller M-1, and higher SQ than the Yuanmou hominoid, indicating a more folivorous or soft diet, such as leaves and berries, in the former. Tooth wear analysis indicates that both upper and lower molars of the Yuanmou hominoid were more heavily worn than those of the Lufeng hominoid, offering additional support to the findings of tooth size proportion and shearing crest development. We propose that different diets might have characterized the two hominoid populations, the differences possibly related to the environment, behavior pattern, and population structure of the Yuanmou and Lufeng hominoids.