An ancient tooth of a mysterious Denisov girl may have been found

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The discovery of an ancient painter – a tooth that probably belonged to a young girl who lived 164,000 years ago in a cave in what is now Laos – is new evidence that a mysterious human line called Denisov is previously known only from the caves of Siberia. and China, also living in Southeast Asia, a new study shows.

“This shows that Denisovites lived in a wide range of environments and latitudes and were able to adapt to extreme conditions, from the cold mountains of the Altai [in Russia] and Tibet to the rainforests of Southeast Asia, ”said Live Science co-author Clement Zanoli, a paleoanthropologist at the University of Bordeaux in France.

“Genetic studies have shown that the Denisovans were adapted to high altitudes and cold climates, but now we also know that they lived in warmer and wetter climates and at lower altitudes,” Zanoli added.

Although modern people Homo sapiensare now the only surviving members of the genus Goma – a family tree of man – once lived other human races Earth. The closest extinct relatives of modern man are the Neanderthals in Europe and Asia and the rediscovered Denisov lines of Asia and Oceania.

The research team is examining sedimentary rocks known as breccias, which they had just carved out of Cobra Cave on the opening day. (Image credit: Fabrice Demeter)

Previous research It is estimated that the ancestors of modern humans separated about 700,000 years ago from the Neanderthals and Denisovans, and the ancestors of the Neanderthals and Denisovans diverged from each other by about 400,000 years ago. However, genetic analysis of the fossils of these extinct pedigrees has shown that they remain close enough to interbreed with modern humans.

Much remains about Denisov. So far, researchers have found only five fossils that are closely related to them – the three upper molars, the finger bone and jaw – which greatly limits what researchers know about them in general. Scientists who discovered the skull in China, christened “The dragon man“claimed to belong to a newly discovered species, Homo longibut many other researchers suspect that it may be Denisov’s skull.

They also argue about where exactly the Denisovites lived. All the fossils found to date came from mainland Asia, but before genetic evidence suggests that people in Oceania and islands in Southeast Asia have a Denisov heritage.

Now the new tooth may be the first fossil evidence of Denisovites in Southeast Asia. “Any additional fossils described as Denisovites are relevant to a better understanding of them. biology and evolution“- told Live Science co-author of the study Fabrice Demeter, a paleoanthropologist from the University of Copenhagen.

Scientists discovered a tooth in 2018 at a site known as the Cobra Cave in the Annamite Mountains of Laos, which has an entrance located about 110 feet (34 meters) above the ground. The limestone cave, technically named Tam Ngu Hao 2, was found because of its proximity to another site where previous research has revealed ancient fossils of modern humans. (Cobra Cave also included animal fossils, for example rhinocerostapirs and sambar deer.)

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This panorama shows Ngu Hao 2 (Cobra Cave) in northern Laos. The entrance to the cave is on the left. (Image: copyright Fabrice Demeter / University of Copenhagen / Paris CNRS)

Figure 2 of 4

Close-up of a hand pointing to evidence of human artifacts carved into a brown cave rock. — The researcher points to the fossils of breccias inside the Cobra Cave. (Image credit: Fabrice Demeter)

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This is an image of the entrance to the Cobra Cave in Laos. It is a rocky and strong cave with many hiding places. In the foreground - the point of long and real strands of white vegetation. — Entrance to the Cobra Cave in Laos. (Image of authorship: Fabrice Demeter)

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View from inside the Denis Cave in the Russian Altai Mountains. Notice how the vegetation and climate are different here compared to Laos.

“Even if the latest results of genetic research suggest that Denisovites and modern humans met in South Asia late. Pleistocene [2.6 million to 11,700 years ago]”We didn’t expect to find a Denisov tooth in Laos,” said Laura Sheckelford, a paleoanthropologist at the University of Illinois at Urbana-Champaign.

The tooth was a molar that had not yet erupted on the left side of the lower jaw. This indicates that it belonged to a child aged 3.5 to 8.5 years. Analysis of dirt and tartar around the tooth using techniques such as luminescent dating, which analyzes how long ago mineral grains were last exposed to sunlight to estimate their age, and radioactive dating, which measures the age of things based on how long it takes to some time. chemical elements before radioactive decay, suggested that the painter was 131,000 to 164,000 years old.

After analyzing the proteins in the tooth enamel, the team confirmed that it is of the genus Goma. Lack of Y-related proteins chromosome suggests that the tooth was from a woman. (Researchers have not analyzed fossils for antiquities DNA because this genetic material is rarely well preserved in the type of sediments found in caves and in tropical conditions present in Laos.)

Different views on the young girl's tooth.

Different views on the young girl’s tooth. (Image credit: Demeter, F. et al. Nature Communications)

When scientists compared this painter to the teeth of other hominins, a group that includes humans, our ancestors, and our closest evolutionary relatives, such as Australopithecus – they found that its internal and external three-dimensional structure resembled that of the Neanderthals, but went a little beyond their known range of variations. What’s more, the tooth was also different from modern man and Homo straight, the first known species of man to use relatively sophisticated stone tools. Although scientists could not rule out that it belonged to a Neanderthal, they suggested that its close physical resemblance to a Denisov specimen from China indicated that the painter was probably Denisov.

“The tooth shows that the Denisovans were actually in Southeast Asia, which is important for understanding their range,” said Live Science Shara Bailey, a paleoanthropologist at New York University who was not involved in the study. “We know that their DNA got there – it is present in the last groups of Southeast Asia – but it shows that the population was also present in the area.”

Even if this new fossil turns out to be non-Denisova, any new human fossil from an area where several ancient human fossils, such as Laos, have so far been found, is “important, especially if it’s non-smart fossils, as it obviously seems, ”said Chris Stringer, a paleoanthropologist at the Natural History Museum in London who was not involved in the study, in an interview with Live Science.

Given this warning, “I think it’s a good study, and the conclusions are strong,” Bailey said. “I agree with their assessment of the tooth.”

New findings may shed light on the extent to which different human lines coexisted. “Neanderthals lived in Europe and Western Asia, while Denisovans occupied much of East Asia along with other human groups such as Homo erectus, Homo floral, Homo luzonensis and modern people, “said Sheckelford.” However, it is unclear when, when and where all these extinct groups could meet. “

These findings suggest that other fossils in Asia need to be re-analyzed using modern methods. “I think we’ll find more Denisovans,” Bailey said. “I know, in particular, one tooth that I saw is probably Denisov.”

When it comes to future research, “I wonder how the tooth got into the cave and whether there is any human activity in the cave,” said Bens Viola, a paleoanthropologist at the University of Toronto who was not involved. work, told Live Science. “Excavations that are now underway must respond to this.”

The scientists published their findings in detail online on May 17 in the journal The nature of communication.

Originally published on Live Science.

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