The Siberian Cave offers the oldest fossils belonging to enigmatic human species

Entrance to the Denisova Cave in Siberia.

Entrance to the Denisova Cave in Siberia.
Image: IAET, Siberian Branch of the Russian Academy of Sciences

The Denisovans, a mysterious group of missing hominids in close contact with Neanderthals, did not leave much fossil evidence behind. A new excavation in their former lands in Siberia has now uncovered three new fossils – the oldest ever found of this species.

Katerina Douka, an evolutionary anthropologist at the University of Vienna, and her colleagues found the fossils in Denisova Cave, a natural shelter in the Altai Mountains in southern Siberia. Scientists have studied the oldest layers in the cave, which have so far failed to produce a single human fossil. A total of five human fossil fragments were recovered: three belonging to Denisovens, one from a Neanderthal and one that could not be identified. The largest of these fragments is no more than 1.6 inches (4 centimeters) long.

Remarkably, this small but precious handful of fossils was found in the middle of a mixture of 3,791 fragments of animal bones. The researchers used a biomolecular method known as a peptide fingerprint to identify the bones, as it was not possible to do so by manual inspection. The five bones contained collagen in accordance with the peptide profiles of humans (peptides are the basic building blocks of proteins), allowing identification (as a reminder, Denisovans and Neanderthals are humans).

Some of the bone fragments recovered in Denisova Cave.

Some of the bone fragments recovered in Denisova Cave.
Image: S. Brown

“Would it have been great to find a new human bone, but five? This has surpassed my wildest dreams, ”said Samantha Brown, co-author of the study and junior group leader at the University of Tübingen, in a Max Planck Institute statement.

Denisova Cave is an “amazing place” when it comes to DNA preservation, and “we have now reconstructed genomes from some of the oldest and best-preserved human fossils,” said Diyendo Massilani, a geneticist at the Max Planck Institute for Evolution. . Anthropology, in edition. The team found enough DNA to reconstruct the mitochondrial genomes, allowing them to confirm that the bones belonged to the Denisovans and Neanderthals. A paper The details of this discovery were published in Nature Ecology & Evolution.

The layer containing the bones of Denisovan was dated to about 200,000 years old. Earlier fossils from Denisova were dated to between 122,000 and 194,000 years ago, so they are now the oldest. The lone Neanderthal bone was dated to 130,000 to 150,000 years ago. The Altai Mountains appear to be “an overlapping area for both the Denisovan and Neanderthal groups of over 150,000 years, assisting and possibly facilitating the population. [interbreeding] as well as the support of distinct hominin populations in this long period ”, according to the paper.

The three new Denisov fossils are in addition to the six already discovered, including a finger bone from which DNA was extracted and a mandible found in a cave on the Tibetan Plateau – the first and only Denisovian fossil found outside Siberia. The Denisovans were closely related to Neanderthals and crossed paths with modern humans before disappearing about 50,000 to 30,000 years ago. Traces of Denisovan DNA exist in the genomes of modern populations in Southeast Asia and Oceania.

According to scientists in their study, “a wealth of archeological material” was found in the Denisovan layer in the form of stone tools and animal remains. This is the first time that archaeological evidence has been definitively linked to these hominins, allowing new perspectives on their behavior.

Interestingly, the style of recovered stone tools, such as scrapers for working animal skins, could not be matched by any known lithic tradition. Living near the Anui River and occupying the caves in a warm period, the people of Denis hunted bison, deer, gas, antelopes and woolly rhinos, in a subsistence pattern that lasted thousands of years, according to the researchers.

These three bones in Denisova are likely to produce more science in the coming years, as will Denisova Cave in general. Slowly but surely, we find out more about these remarkable people.

More: Scientists have discovered a hot spot of Denisov’s ancestors.

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