Institute of Cultural Heritage, Shandong University, 72 Jimo-Binhai Road, Qingdao, 266237, China.
Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY, 10003, USA.
J Hum Evol. 2024 Apr;189:103507. doi: 10.1016/j.jhevol.2024.103507. Epub 2024 Feb 27.
The rarity of Pongo fossils with precise absolute dating from the Middle Pleistocene hampers our understanding of the taxonomy and spatiotemporal distribution of Quaternary orangutans in southern China. Here, we report a newly discovered sample of 113 isolated teeth of fossil Pongo from Zhongshan Cave in the Bubing Basin, Guangxi, southern China. We describe the Pongo specimens from Zhongshan Cave and compare them metrically to other samples of fossil Pongo species (i.e., Pongo weidenreichi, Pongo devosi, Pongo duboisi, Pongo palaeosumatrensis, Pongo javensis, and Pongo sp.) and to extant orangutans (i.e., Pongo pygmaeus and Pongo abelii). The Zhongshan Pongo assemblage is dated using U-series and coupled electron spin resonance/U-series methods. Our results reasonably constrain the Zhongshan Pongo assemblage to 184 ± 16 ka, which is consistent with the biostratigraphic evidence. The Zhongshan Pongo teeth are only 6.5% larger on average than those of extant Pongo. The Zhongshan teeth are smaller overall than those of Pongo from all other cave sites in southern China, and they currently represent the smallest fossil orangutans in southern China. Based on their dental size, and the presence of a well-developed lingual pillar and lingual cingulum on the upper and lower incisors, an intermediate frequency of lingual cingulum remnants on the upper molars, and a higher frequency of moderate to heavy wrinkling on the upper and lower molars, we provisionally assign the Zhongshan fossils to P. devosi. Our results confirm earlier claims that P. weidenreichi is replaced by a smaller species in southern China, P. devosi, by the late Middle Pleistocene. The occurrence of P. devosi in Zhongshan Cave further extends its spatial and temporal distribution. The Pongo specimens from Zhongshan provide important new evidence to demonstrate that the dental morphological features of Pongo in southern China changed substantially during the late Middle Pleistocene.
中更新世中期具有精确绝对测年的猩猩化石的稀有性阻碍了我们对中国南方第四纪猩猩的分类和时空分布的理解。在这里，我们报告了一个在中国广西 bubing 盆地中山洞新发现的 113 颗孤立的化石猩猩牙齿样本。我们描述了中山洞的猩猩标本，并与其他化石猩猩物种（即 Pongo weidenreichi、Pongo devosi、Pongo duboisi、Pongo palaeosumatrensis、Pongo javensis 和 Pongo sp.）以及现生猩猩（即 Pongo pygmaeus 和 Pongo abelii）进行了比较。使用 U 系列和电子自旋共振/U 系列联合方法对中山洞的 Pongo 组合进行了年代测定。我们的结果合理地将中山洞的 Pongo 组合限定在 184±16ka，这与生物地层学证据一致。中山洞的猩猩牙齿平均比现生猩猩的牙齿大 6.5%。总的来说，中山洞的牙齿比中国南方所有其他洞穴地点的猩猩牙齿都要小，而且它们目前是中国南方最小的化石猩猩。根据牙齿大小，以及上下切牙上发达的舌柱和舌环，上颌磨牙上舌环遗迹的出现频率中等，上下磨牙上中度到重度褶皱的出现频率较高，我们将中山洞的化石暂定为 P. devosi。我们的结果证实了早期的说法，即中更新世晚期，中国南方的 P. weidenreichi 被一个较小的物种 P. devosi 所取代。P. devosi 在中山洞的出现进一步扩展了它的时空分布。中山洞的 Pongo 标本提供了重要的新证据，证明了中国南方 Pongo 的牙齿形态特征在中更新世晚期发生了重大变化。
