A low, sloping forehead, a massive brow ridge that curves backwards, rectangle-like eye sockets, flat cheeks and a moderately elevated bridge of the nose. Taken together, these features are the hallmarks of the ancient humans called the Denisovans, say researchers who studied a trove of fossilized skull fragments, teeth and jaws found in northern China.
“We are finally starting to put a face to the Denisovan,” says Sally Wasef, a palaeogeneticist at the Queensland University of Technology in Brisbane, Australia.
Denisovans were first described in 2010, after researchers sequenced genetic material from a mysterious finger bone discovered in a cave in Siberia and found that it did not resemble that of Homo sapiens or Neanderthals (Homo neanderthalensis). Ancient proteins have since been used to identify remains from other parts of Asia as Denisovan, including the first near-complete Denisovan skull found near Harbin, which helped to put a face to the ancient humans.
Researchers report in Nature1 today that they have an even better idea of what Denisovans looked like after analyzing the physical features of remains that belong to a collection of 20 fossils found in Xujiayao.
The Xujiayao remains are at least 130,000 years old and were found in the 1970s, alongside animal remains and tools. At the time, it was unclear what type of human these fossils belonged to, and they were classified as a species called Homo juluensis. By analyzing ancient proteins from some of the fossils, Qiaomei Fu, a geneticist at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, and her team identified the remains as Denisovan.
Wasef says that ancient-protein analysis is a valuable tool to complement DNA studies, particularly because proteins can survive longer without fully degrading than can DNA. Although DNA provides more-detailed information about an individual, protein analysis can still yield useful information about who an individual is related to.
Fabrice Demeter, a palaeoanthropologist at the University of Copenhagen, says that the findings add to growing evidence that Denisovans were a widespread and potentially diverse group of humans. “The study represents a major step forward” in our understanding of what these humans could have looked like and where they lived.