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. 2023 May;178:103348. doi: 10.1016/j.jhevol.2023.103348. Epub 2023 Mar 24.
The Pongo fossil record of China extends from the Early Pleistocene to the Late Pleistocene, but to date, no late Middle Pleistocene samples of Pongo with precise absolute dating have been identified in southern China. Here, we report the recovery of 106 fossil teeth of Pongo from Ganxian Cave in the Bubing Basin, Guangxi, southern China. We dated the speleothems using Uranium-series and dated the two rhinoceros teeth using coupled electron spin resonance/Uranium-series dating methods to between 168.9 ± 2.4 ka and 362 ± 78 ka, respectively. These dates are consistent with the biostratigraphic and magnetostratigraphic age estimates. We further describe the fossil teeth from Ganxian Cave and compare them metrically to samples of fossil Pongo (i.e., Pongo weidenreichi, Pongo duboisi, Pongo palaeosumatrensis, Pongo javensis, and Pongo sp.) from the Early, Middle, and Late Pleistocene and to extant Pongo (i.e., Pongo pygmaeus and Pongo abelii) from Southeast Asia. Based on overall dental size, a high frequency of lingual cingulum remnants on the upper molars, and a low frequency of moderate to heavy wrinkling on the molars, we attribute the Ganxian fossils to P. weidenreichi. Compared with Pongo fossils from other mainland Southeast Asia sites, those from Ganxian confirm that dental size reduction of Pongo occurred principally during the Early and Middle Pleistocene. From the Middle to Late Pleistocene, all teeth except the P show little change in occlusal area, indicating that the size of these teeth remained relatively stable over time. The evolutionary trajectory of the Pongo dentition through time may be more complex than previously thought. More orangutan fossils with precise dating constraints are the keys to solving this issue.
中国的猩猩化石记录可追溯到更新世早期至更新世晚期，但迄今为止，在中国南方尚未发现具有精确绝对测年的中更新世晚期的猩猩样本。在这里，我们报告了在广西 bubing 盆地甘贤洞发现的 106 颗猩猩化石牙齿。我们使用铀系法对洞穴石笋进行了测年，并用电子自旋共振/铀系测年法对两颗犀牛牙齿进行了测年，结果分别为 168.9±2.4ka 和 362±78ka。这些日期与生物地层学和磁地层学的年龄估计值一致。我们进一步描述了甘贤洞的化石牙齿，并在度量上与早期、中期和晚期更新世的化石猩猩（即 Pongo weidenreichi、Pongo duboisi、Pongo palaeosumatrensis、Pongo javensis 和 Pongo sp.）以及来自东南亚的现生猩猩（即 Pongo pygmaeus 和 Pongo abelii）进行了比较。基于整体牙齿大小、上颌臼齿舌侧齿带的高出现频率，以及臼齿中度至重度皱缩的低出现频率，我们将甘贤洞的化石归入 Pongo weidenreichi。与来自其他东南亚大陆地点的猩猩化石相比，来自甘贤洞的化石证实了猩猩的牙齿尺寸减小主要发生在更新世早期和中期。从中更新世到晚更新世，除了 P 之外的所有牙齿的咬合面积都没有明显变化，这表明这些牙齿的大小在一段时间内保持相对稳定。猩猩牙齿随时间的进化轨迹可能比以前认为的更为复杂。解决这个问题的关键是获得更多具有精确测年限制的猩猩化石。
