Denisovans had a distinctive look, protein and skull study suggests

Key Points:

• Scientists extracted ancient proteins from two bones at the Xujiayao site in northern China, identifying the individuals as Denisovans, a finding that clarifies the classification of East Asian fossils previously debated as Neanderthals, archaic Homo sapiens, or Homo juluensis.
• Protein analysis focused on a specific amino acid in collagen, revealing the Denisovan marker lysine instead of arginine found in Neanderthals and modern humans, with over 99% statistical support placing the fossils within the Denisovan lineage.
• Morphological examination showed Xujiayao skulls have distinct features such as thick bone walls and a strongly arched temporal bone, traits shared with other Chinese fossils like Harbin, suggesting these too are Denisovan and extending the group's geographic range from Siberia to Taiwan and temporal range from 300,000 to 45,000 years ago.
• Despite initial concerns about brain size differences, the Xujiayao specimen's brain volume falls within the modern human range, indicating normal variation within the Denisovan population rather than a distinct species-level difference.