WASHINGTON — Scientists have assembled one of the clearest pictures yet of what the Denisovans looked like, using ancient protein analysis and skull fragments to reconstruct the facial features of the extinct human relative.
In a study published in the journal Nature, an international research team analyzed a collection of 20 fossils excavated from Xujiayao, a prehistoric site in eastern China. By examining surviving collagen peptides, the researchers confirmed the remains belonged to Denisovans and identified physical traits that distinguish them from modern humans and Neanderthals.
A blend of ancestral features
Denisovans possessed a relatively long, low cranial profile, a massive brow ridge, rectangular eye sockets, flat cheekbones and a slightly protruding jaw, Gizmodo reported, citing the study and a translated statement from the Chinese Academy of Sciences’ Institute of Vertebrate Paleontology and Paleoanthropology.
The physical structure displayed a mix of evolutionary characteristics, Nautilus reported. Researchers noted that the thick, wide skull cap mirrored Homo erectus, while the inner ear cavity aligned with Neanderthals, and the tall sides of the vaulted cranium resembled those of modern humans.
To evaluate the physical structure, the team compared the Xujiayao fossils and a near-complete specimen known as the Harbin cranium against roughly 200 hominin remains from other species, according to Nature News and Nautilus.
“This exercise may come in handy when classifying other fossils that we don’t yet realize are Denisovan,” Qiaomei Fu, a geneticist at the Chinese Academy of Sciences and corresponding author of the study, told Nature News.
Proteins crack the identification barrier
First identified from a finger bone found in Russia’s Denisova Cave in 2008, Denisovans were confirmed through DNA in 2010 as a distinct branch of archaic humans. Yet while genetic sequences have proved that Denisovans once roamed across Asia and interbred with both Neanderthals and modern humans, intact fossils have remained exceptionally scarce.
At Xujiayao, where bones were unearthed in the 1970s alongside stone tools and animal remains, age estimates differ slightly across reports. Gizmodo noted the fossils date to between 138,000 and 199,000 years old, while Nautilus cited an age of around 130,000 years.
Because ancient DNA degrades quickly in temperate and warm environments, the researchers turned to paleoproteomics. The team detected a specific amino acid substitution that appears in verified Denisovan specimens but is absent in Neanderthal and modern human bones, the Chinese Academy of Sciences stated.
Sally Wasef, a paleogeneticist at Queensland University of Technology who was not involved in the research, told Nature News that while DNA offers richer details, ancient proteins survive for far longer spans and still supply critical genetic background.
What remains unknown
Researchers caution that a single facial portrait does not capture the entire species. Denisovans inhabited diverse climates over hundreds of thousands of years, likely developing regional physical differences.
- Fabrice Demeter, a paleoanthropologist at the University of Copenhagen, told Nature News that geographic distribution across vast stretches of time suggests variations in morphology within the species.
- The Chinese Academy of Sciences noted that previous evidence showed Neanderthals experienced genetic shifts from interbreeding, a pattern that Denisovans probably mirrored.
- The researchers stated the latest findings challenge older theories that East Asian hominin populations in the Middle Pleistocene were hopelessly chaotic.
Scientists expect future excavations across Asia and further refinements in protein sequencing to clarify whether these skull traits were shared by all Denisovan groups or represent local adaptations.
