Denisovans were members of a hominin group previously known from genome studies of fragmentary fossils from only one site – the Denisova Cave in Siberia – as well as from genetic traces among several low-altitude East Asian populations and high-altitude modern Tibetans.  

Lack of morphologically informative Denisovan fossils has hindered our ability to connect geographically and temporally dispersed fossil hominins across Asia and understand their relation to recent Asian populations. It has also inhibited our understanding of human genetic adaptation to the high-altitude Tibetan Plateau, which was inherited from the Denisovans. 

This situation dramatically changed with the discovery of a Denisovan mandible by a team led by CHEN Fahu, an Academician from the Center for Excellence in Tibetan Plateau Earth Sciences and the Institute of Tibetan Plateau Research of the Chinese Academy of Sciences.  

The mandible was found in the Baishiya Karst Cave of Xiahe County in northwestern China’s Gansu Province. U-series dating of an adhering carbonate matrix shows that the mandible is at least 160,000 years old. The Xiahe specimen provides direct evidence of Denisovans outside the Altai Mountains and protein analysis provides insights into Denisovan mandibular and dental morphology. 

The results show that archaic hominins occupied the Tibetan Plateau in the Middle Pleistocene epoch and successfully adapted to high-altitude hypoxic environments long before the regional arrival of modern Homo sapiens. 

The results were published online in Nature. The discovery was listed among the Top 10 Breakthroughs of 2019 by Science Magazine, the Top 10 Discoveries by Archaeology and the Top 10 Stories in Science News in 2019. 

Denisovan mandible from Baishiya Karst Cave