New Discovery Fills Long-Missing Gap in Evolutionary History - SciTechDaily

The oldest gibbon fossil was discovered successful southwest China.

The earliest gibbon fossil has been recovered by a squad of researchers, filling a long-missing evolutionary spread successful the past of apes.

The study, which was published successful the Journal of Human Evolution, focuses connected the hylobatid household of apes, which comprises 20 taxon of surviving gibbons that are recovered passim tropical Asia from northeastern India to Indonesia.

“Hylobatids fossil remains are precise rare, and astir specimens are isolated teeth and fragmentary jaw bones recovered successful cave sites successful confederate China and southeast Asia dating backmost nary much than 2 cardinal years ago,” explains Terry Harrison, a prof of anthropology astatine New York University and 1 of the paper’s authors. “This caller find extends the fossil grounds of hylobatids backmost to 7 to 8 cardinal years agone and, much specifically, enhances our knowing of the improvement of this household of apes.”

The fossil, recovered successful the Yuanmou country of Yunnan Province successful southwestern China, is of a tiny ape called Yuanmoupithecus xiaoyuan. The study’s analysis concentrated connected the teeth and cranial specimens of Yuanmoupithecus, which included an precocious jaw from a young kid who was little than 2 years aged astatine the clip of its death.

Using the size of the molar teeth arsenic a guide, Yuanmoupithecus was estimated to be close successful size to modern-day gibbons, with a assemblage value of astir 6 kilograms—or astir 13 pounds.

“The teeth and the little look of Yuanmoupithecus are precise akin to those of modern-day gibbons, but successful a fewer features the fossil taxon was much primitive and points to it being the ancestor of each the surviving species,” observes Harrison, portion of NYU’s Center for the Study of Human Origins.

Ji discovered the child’s precocious jaw during a tract survey, and by comparing it with modern gibbon skulls kept astatine the Kunming Institute of Zoology, helium was capable to place it arsenic a hylobatid. In 2018, helium invited Harrison and different colleagues to enactment connected specimens gathered implicit the erstwhile 30 years that were housed successful the Yunnan Institute of Cultural Relics and Archaeology and the Yuanmou Man Museum.

“The remains of Yuanmoupithecus are highly rare, but with diligence, it has been imaginable to retrieve capable specimens to found that the Yuanmou fossil ape is so a adjacent comparative of the surviving hylobatids,” notes Harrison.

The Journal of Human Evolution survey besides recovered that Kapi ramnagarensis, which has been claimed to beryllium an earlier taxon of hylobatid, based connected a azygous isolated fossil molar from India, is not a hylobatid aft all, but a subordinate of a much primitive radical of primates that are not intimately related to modern-day apes.

“Genetic studies bespeak that the hylobatids diverged from the lineage starring to the large apes and humans astir 17 to 22 cardinal years ago, truthful determination is inactive a 10-million-year spread successful the fossil grounds that needs to beryllium filled,” Harrison cautions. “With the continued exploration of promising fossil sites successful China and elsewhere successful Asia, it is hoped that further discoveries volition assistance capable these captious gaps successful the evolutionary past of hylobatids.”

Reference: “The earliest hylobatid from the Late Miocene of China” by Xueping Jia, Terry Harrison, Yingqi Zhang, Yun Wub, Chunxia Zhang, Jinming Hui, Dongdong Wua, Yemao Hou, Song Li, Guofu Wang and Zhenzhen Wang, 13 September 2022, Journal of Human Evolution.
DOI: 10.1016/j.jhevol.2022.103251

The survey was funded by the National Natural Science Foundation of China, the Yunnan Natural Sciences Foundation, and the Strategic Priority Research Program of the Chinese Academy of Sciences. 

The researchers besides received entree to skeletal and paleontological collections astatine the American Museum of Natural History successful New York and the Smithsonian Institution’s National Museum of Natural History successful Washington D.C., among others, successful conducting their study.