The discovery of new fossils and tools of the extinct species known as the Denisovans reveals new clues about mysterious humans who, it is now known, inhabited almost all of Asia and lived continuously in southwest China for 120,000 years, successfully adapting to very different environments.
This discovery, made in the Chinese cave of Bianfu, in Yunnan province, provides key data about hominins who had a common ancestor with Neanderthals and who left their genetic mark on current populations of Southeast Asia and Oceania, but about whose life strategies little was known. In fact, the Denisovans still do not have an official scientific name assigned as a species of the genus Homo because the known remains are not sufficient for their physical description.
According to the researchers, as published this week in the journal Nature, they found in that Chinese cave four teeth, two skull fragments, and a radius that belonged to three different individuals. According to dating, they lived between 167,000 and 134,000 years ago, at different times, although tools have also been found in layers indicating they were in that place much longer: from 190,000 to 70,000 years ago. No other site has so far yielded such an extensive record of these extinct hominins.
The first remains of the species were discovered in 2008 in the Russian Denisova cave in Siberia. It was the first—and so far only—known thanks to DNA sequencing extracted from a fragment of a pinky and some molars. In the years following that date, some more fossils were found: a jaw in the Baishiya cave in Tibet—studied by the team of paleontologist Jean-Jacques Hublin, from the Collège de France in Paris, who also participated in this work; some remains caught in fishing nets in Taiwan, about which there are doubts; a molar much further south, in Laos, also debated; and a skull in Harbin, northeast China. These findings gave few clues about how they might have lived. Also, they were very distant points, so a geographic bridge was missing to understand how the Denisovans expanded from the north to the south of the continent, where it is thought they successfully hybridized with Homo sapiens. From there, it is believed that the trace of their DNA in current populations, ranging between 4% and 6%, comes.
Now the connection is established: the new fossils confirm that these humans inhabited a vast region stretching from Siberia, passing through the Qinghai plateau in Tibet, where they lived at altitudes of 3,200 meters, occupying the Yunnan-Guizhou plateau in the southwest, and reaching the tropical lands of Laos. “Due to the genomic evidence of that Denisovan ancestry in current populations, this region seemed a key area for their dispersion, and these findings confirm it,” explains to La Vanguardia the research coordinator, paleontologist Qiaomei Fu, from the Chinese Academy of Sciences.
The site, Fu recalls, was located in April 2019 during restoration work of an old quarry. After a preliminary study by local scientists, a thorough excavation was carried out in which they found 60,000 animal fossils and 1,300 tools. After an initial analysis, 22 remains that could be hominin were located and studied by mass spectrometry. The researchers were looking for proteins that would allow them to identify them with certainty.
“That’s how we identified amino acid variants that are only from Denisovans. What there wasn’t is DNA because it degrades more than proteins and these are fossils over 100,000 years old (Denisova’s are 40,000); also the climate in Yunnan was warmer than in Siberia,” explains the scientist. For now, they do not know if these individuals who lived at different times in Bianfu are more related to each other than to Denisovans from other sites, “but they seem to be from other lineages of the same species.”
The scientists also highlight the importance of now having the fragment of an arm bone, the radius, because until now almost nothing was known about their skeleton. In this case, they see similarity with some Neanderthal traits, from whose common ancestor they separated about half a million years ago, although they also see that its external shape resembles that of modern humans, so they describe it as a “mosaic pattern.”
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Jean-Jacques Hublin, who is working in a cave in Tibet, emphasizes via email how important it is to have precisely documented remains. “My work has been the evolutionary interpretation of human fossils, which combined with molecular evidence begins to define more precisely what this species represented biologically. Studies of these and other fossils indicate it was morphologically distinct from others, so we are reaching the point where the question of assigning them a name within the genus Homo can be seriously addressed,” he argues. “It was a group known through genetics and now all these findings in China allow its study through anatomy, ecology, and archaeological context.”
For example, it is known that during the period they lived in that Chinese cave, the climate was relatively warm. Fossilized pollen has shown that their environment had conifer forests and steppes, a suitable habitat for large herbivores, such as deer and water buffalo, of which there are numerous remains at the site. In short, the Yunnan-Guizhou plateau could have been a “paradise” for hunting for these primitive humans.
Also, the 1,300 tools found in different sediment layers give clues about their behavior. The Denisovans used technologies very similar to those of their relatives, the Eurasian Neanderthals, although that does not mean they copied them, according to Hublin. All are very simple tools, which would indicate that instead of spending time making them, they preferred a strategy of taking advantage of the natural shape of stones. They also used animal bones they had on hand, without even modifying them.
Canadian archaeologist Luc Doyon, currently at the University of the Basque Country, was in charge of their study as a specialist in bone tools. He explains that they used them to retouch and sharpen stone tools with which they processed meat and skins: “In 2023 I went to China to see the material and I found it was equipment very similar to that also used by early European Neanderthals, with very basic shapes. It was a human species with a great capacity to adapt to very different environments.”
Doyon advocates the need to re-study human remains found in the 1940s or 1950s, when it was already seen that some fossils had differences with Neanderthals and sapiens, to see if the number of Denisovan fossils increases. “Now it could be checked if they are Denisovans if some DNA or proteins are preserved, as has happened in this case,” he points out.
For his part, the French Hublin, known worldwide for having found in Morocco the oldest Homo sapiens remains, 315,000 years old, considers that thanks to this discovery “the idea is reinforced that human history in the Middle Pleistocene of Asia was more complex than a replacement of Homo erectus by sapiens. (…) Different populations existed in different parts and for very long periods. Thanks to genetics, we know that occasionally Denisovans interacted with Neanderthals and sapiens in the same territories, but it also tells us that there were no complete replacements, but partial replacements,” he concludes.
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