2022-09-14 ニューヨーク大学 (NYU)
The upper jaw of the infant of Yuanmoupithecus. Image courtesy of Terry Harrison, NYU’s Department of Anthropology.
この化石は、インド北東部からインドネシアにかけての熱帯アジアに生息する20種のテナガザルを含む類人猿の一種、ハイロバチッド類に由来している。
ハイロバチッド類の化石は非常に珍しく、そのほとんどは、中国南部と東南アジアの洞窟遺跡から200万年以上も前に見つかった単体の歯と断片的な顎の骨だが、この新しい発見は、ヒイロバチの化石記録を700万年から800万年前まで遡らせ、より具体的には、この類人猿の仲間の進化に関する我々の理解を深めるものである。
<関連情報>
- https://www.nyu.edu/about/news-publications/news/2022/september/earliest-gibbon-fossil-found-in-southwest-china.html
- https://www.sciencedirect.com/science/article/abs/pii/S0047248422001117?via%3Dihub
中国後期中新世から出土した最古のハイロバチッド類 The earliest hylobatid from the Late Miocene of China
Xueping Ji,Terry Harrison,Yingqi Zhang,YunWu,Chunxia Zhang,Jinming Hu,Dongdong Wu,Yemao Hou,SongLi,Guofu Wang,Zhenzhen Wang
Journal of Human Evolution Available online: 13 September 2022
DOI:https://doi.org/10.1016/j.jhevol.2022.103251
Abstract
Yuanmoupithecus xiaoyuan, a small catarrhine from the Late Miocene of Yunnan in southern China, was initially suggested to be related to Miocene proconsuloids or dendropithecoids from East Africa, but subsequent reports indicated that it might be more closely related to hylobatids. Here, detailed comparisons of the material, including seven newly discovered teeth and a partial lower face of a juvenile individual, provide crucial evidence to help establish its phylogenetic relationships. Yuanmoupithecus exhibits a suite of synapomorphies that support a close phylogenetic relationship with extant hylobatids. Furthermore, based on the retention of several primitive features of the dentition, Yuanmoupithecus can be shown to be the sister taxon of crown hylobatids. The contention that Kapi ramnagarensis from the Middle Miocene of India might represent an earlier species of hylobatid is not supported here. Instead, Kapi is inferred to be a specialized pliopithecoid more closely related to Krishnapithecus krishnaii from the Late Miocene of India. Currently then, Yuanmoupithecus represents the earliest known definitively identified hylobatid and the only member of the clade predating the Pleistocene. It extends the fossil record of hylobatids back to 7–8 Ma and fills a critical gap in the evolutionary history of hominoids that has up until now remained elusive. Even so, molecular estimates of a divergence date of hylobatids from other hominoids at about 17–22 Ma signifies that there is still a substantial gap in the fossil record of more than 10 million years that needs to be filled in order to document the biogeographic origins and early evolution of hylobatids.
