Early gibbon fossils found in southwest China: This discovery fills a gap in the evolutionary history of great apes

The study, published in the Journal of Human Evolution, was conducted on hylobatids, a species of ape that includes 20 extant species of gibbons that are found throughout tropical Asia from northeastern India to Indonesia

Terry Harrison, a professor of anthropology at New York University and one of the paper's authors, explains: "Hylobatids fossil remains are very rare, with most specimens containing isolated teeth and broken jaws

The fossil was found in the Yuanmou region of Yunnan Province in southwestern China and belongs to a small ape

Taking the size of the molars as a reference, scientists estimate that the "Yuanmoupithecus xiaoyuan" was similar in size to today's gibbons, weighing about 6 kilograms (about 13 pounds).

Harrison, of the Center for The Study of Human Origins at New York University, said: "The teeth and lower face are very similar to modern gibbons, but in some features, this fossil species is more primitive, indicating that it is the ancestor

Ji found the cub's maxilla during a field survey and compared it to the modern gibbon skull at the Kunming Institute of Zoology to identify it as a mandible

"The remains of Yuanmoupithecus are extremely rare, but through effort, it is possible to find enough specimens to determine that the Yuanmoupithecus fossil is indeed a close relative of the extant lower lobe ape," Harrison noted

The Journal of Human Evolution study also found that, according to a separate molar fossil from India, it is believed to be an early primate, Kapi ramnagarensis, which is not a primate at all, but a member of a more primitive primate group and is not closely

"Genetic studies have shown that around 17 to 22 million years ago, the lineages of great apes and humans began to diverge, so there are still 10 million-year-old gaps in the fossil record that need to be filled," Harrison warned

In the course of conducting the research, the researchers also acquired skeletal and paleontological collections

Xueping Ji, Terry Harrison, Yingqi Zhang, Yun Wu, Chunxia Zhang, Jinming Hu, Dongdong Wu, Yemao Hou, Song Li, Guofu Wang, Zhenzhen Wang.