The Diet of the Yuanmou Hominoid, Yunnan Province, China: An Analysis from Tooth Size and Morphology

Abstract

In the past decades numerous late Miocene hominoid fossils have been discovered in Eurasia but the relationships among them and to the later hominids are still in debate. Yunnan Province of China is one of the key places of hominoid fossil discoveries. Till now, four sites have yielded Miocene hominoid fossils. Among them, Lufeng and Yuanmou rank with Siwalik as the richest fossil sites in Eurasia. Here, we report the results of a dietary analysis of the Yuanmou hominoid. Our analyses of tooth size proportions. M₂ shearing crest development, tooth enamel thickness and body weight of Yuanmou and other Miocene hominoids indicate that, compared with other samples, the Yuanmou hominoid had relatively bigger front teeth and weakly developed molar shearing crests (lower SQ). So, the Yuanmou hominoid is considered to have mainly fed on a harder or frugivorous diet. Among the other Miocene hominoids considered in present study, the SQs of Proconsul nyanzae, Ouranopithecus macedoniensis, Dendropithecus macinnesis and Lufengpithecus lufengensis is close to that of Yuanmou indicating that they had similarly developed molar shearing crests with a likely preference for hard fruits. On the other hand, there are some differences between the Yuanmou hominoid and Lufengpithecus in all the four aspects of evidence studied here. Among them, Lufengpithecus had relatively smaller front teeth, relatively smaller M¹, higher SQ, indicating that more folivorous and soft dietary items like leaves and berries were consumed. The preferred paleoenvironments of the Yuanmou hominoid and Lufengpithecus might also have been different.