Featuring a pronounced brow ridge and a brain size comparable to that of modern humans and Neanderthals, the Denisovans, an ancient human group, are now better understood thanks to recent studies reported in Cell and Science.

Paleontologists have utilized ancient molecular data to classify a skull discovered near Harbin in northeastern China as belonging to the Denisovans. This skull marks the first near-complete cranium to be definitively associated with these extinct humans.

Dating back at least 146,000 years, this fossil puts an end to over a decade of speculation about the physical appearance of the Denisovans, which has been elusive since their initial identification through unique DNA sequences found in a finger bone in a Siberian cave in 2010.

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“Having Denisovan DNA from a nearly complete cranium is truly exciting,” states Janet Kelso, a computational biologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. “We now have a glimpse into the cranial features of the Denisovans,” she adds.

“Having Denisovan DNA from a nearly complete cranium is truly exciting,” states Janet Kelso, a computational biologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. “We now have a glimpse into the cranial features of the Denisovans,” she adds.

Dragon Man

Described as “massive,” the cranium—comprising the upper portion of the skull minus the lower jaw—is among the best-preserved specimens of all archaic human fossils, according to the researchers who first outlined its significance in 2021.

In 2018, Qiang Ji, a paleontologist at Hebei GEO University in Shijiazhuang, China, acquired the specimen from an unidentified individual. Ji suspects this man unearthed the artifact himself but did not report it to the authorities. He claimed that his grandfather found the fossil in 1933 while carrying out bridge construction over the Long Jiang (Dragon River), and subsequently hid it in an abandoned well, where it stayed hidden until revealed in a deathbed confession.

In 2021, Ji and his team determined that the ‘Dragon Man’ skull represents a distinct species of archaic humans, which they named Homo longi⁴.

Unraveling the Molecular Puzzle

Following the publication of these findings, Ji was contacted by Qiaomei Fu, a geneticist at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing. Fu, who had previously worked on the first Denisovan DNA derived from the Siberian finger bone, was eager to determine if the Dragon Man fossil contained any ancient molecular traces.

Fu’s team initially attempted to extract ancient DNA from the skull’s petrous bone—a reliable source—and from an attached tooth. While they failed to recover any genetic material, they managed to extract and sequence fragments from 95 ancient proteins from the petrous samples.

Fu compared these protein sequences with those from Neanderthals, modern humans, and other Denisovans. One protein sequence from the Harbin fossil matched exactly with a protein from the Siberian finger bone, as well as Denisovan specimens from Tibet and Taiwan, but differed from those in modern humans and Neanderthals. This strongly indicated that the individual was a Denisovan. Fu’s team also identified two other, less definitive, protein matches.

Earlier this year, other researchers used ancient proteins to identify a Taiwanese jawbone as Denisovan. Takumi Tsutaya, a bioarchaeologist at the Graduate University for Advanced Studies in Kanagawa, Japan, expressed his amazement at learning another Denisovan had been identified so soon.

Seeking additional proof, Fu turned to a small chip of calcified dental plaque, or calculus. She searched for host DNA among the bacterial DNA in the sample and found it. Genetic sequences from the maternally inherited mitochondrial genome of the Dragon Man skull closely matched those of early Denisovans from Siberia, dated between 187,000 and 217,000 years ago. Fu noted that this was the first time host DNA had been recovered from dental calculus dating back to the Paleolithic era, which ended 12,000 years ago.

Rikai Sawafuji, a geneticist at Kyushu University in Fukuoka, Japan, who worked on the Taiwanese fossil, was surprised that the team managed to recover human DNA from the calculus, given the failure with the petrous bone. She believes this discovery could encourage other researchers to analyze ancient plaque from Paleolithic fossils. “If there is some dental calculus,” she remarks, “people can extract human mitochondrial DNA from those samples” to further our understanding of prehistoric human migrations.

Importantly, scientists now have access to a Denisovan cranium, which can serve as a reference for identifying other Denisovan specimens in their collections, even in the absence of recoverable ancient DNA or proteins.

This article is reproduced with permission and was first published on June 18, 2025.