Pongo化石的稀有性与中更新世的精确绝对年代有关，这阻碍了我们对中国南方第四纪猩猩的分类学和时空分布的理解。这里,我们报告了布冰盆地中山洞新发现的113颗孤立牙齿化石的样本，广西,中国南方。我们描述了中山洞的Pongo标本，并将其与化石Pongo物种的其他样本进行了计量比较（即，Pongoweidenreichi,PongoDevosi,Pongoduboisi,Pongopalaeosumatrensis,Pongojavensis,和Pongosp.)和现存的猩猩(即，Pongopygmaeus和Pongoabelii）。中山庞戈组合的年代采用U系列和耦合电子自旋共振/U系列方法。我们的结果合理地将中山庞戈组合限制在184±16ka，这与生物地层学证据是一致的。中山庞戈的牙齿平均仅比现有庞戈的牙齿大6.5％。中山牙齿总体上比中国南方所有其他洞穴遗址的Pongo牙齿小，它们目前代表了中国南方最小的猩猩化石。根据牙齿的大小,上下切牙上有发达的舌柱和舌带，上磨牙上舌扣带残留物的中频，上磨牙和下磨牙的中度至重度起皱频率更高，我们暂时将中山化石分配给P.devosi。我们的结果证实了先前的说法，即P.weidenreichi在中国南方被较小的物种取代，P.Devosi,到中更新世晚期。中山洞中紫花苜蓿的发生进一步扩展了其时空分布。中山的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实质性变化。
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.
