This is what the mysterious Denisovans looked like

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 skulls, 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. 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 put a face on the ancient humans.

Researchers report in Nature¹ today that they have an even better idea of what Denisovans looked like after analysing 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 analysing 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 ancient protein analysis is a valuable tool to complement DNA studies, particularly because proteins can survive longer than can DNA without fully degrading. 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 in Denmark, says 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.

Face to the name

Fu’s team analysed small fragments of proteins, called peptides, from two Xujiayao bones and compared them with peptides found in humans and Neanderthals. They found a single amino-acid change that was present in multiple peptides from the Xujiayao bones and other East Asian fossils and is a known genetic marker for identifying Denisovans. The amino-acid change was not seen in human or Neanderthal samples.