Fossil Proteins Identify a Disputed Chinese Skull as Denisovan

Song Xing, Qiaomei Fu and colleagues at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing report that proteins from two fossils at Xujiayao, in northern China, carry a variant so far seen only in Denisovans. The paper appeared Oct. 21, 2026, in Nature and is open access.

Denisovans were defined by DNA from remains in Siberia, and which other Asian fossils belong with them has been disputed since. The new analysis turns on a single position in a collagen protein, COL1A2-996: the authors report that the Denisovan form there is present in every Denisovan so far identified by DNA or protein, while Neanderthals and modern humans carry a different amino acid. It can place a fossil that has yielded no genome.

The two specimens were a piece of skull and a jaw fragment. The authors report 18 proteins they judge ancient rather than modern contamination, the Denisovan marker in both bones, and a family tree built from the protein sequences that put the samples with known Denisovans every time.

Xing and colleagues then compared Xujiayao with other East Asian fossils of the same period, among them Harbin, Jinniushan, Dali and Hualongdong, and set out traits they share: a low braincase with nearly parallel side walls, a heavy brow ridge, a flat cheek region and a face that barely juts forward. They describe this as indicating that all belong to the Denisovan lineage, an inference from shared anatomy and not a molecular result for each fossil.

The paper notes an earlier analysis that measured the Xujiayao 6 braincase at 1,700 ml, grounds for putting Xujiayao in a separate species, Homo juluensis. Xing and colleagues argue that the gap in brain size between the two groups falls inside the range recorded in living people, and counts as variation within one population.

The Xujiayao fossils come from the Nihewan Basin and are dated to roughly 199,000 to 138,000 years ago. The protein data are deposited in the public PRIDE repository.