Denisovans, a mysterious group of extinct hominins closely related to Neanderthals, haven’t left much fossil evidence behind. A new excavation in the former trampling grounds of Siberia has yielded three new fossils – the oldest yet found of this type.
Evolutionary anthropologist Katerina Duka from the University of Vienna and her colleagues found the fossils in Denisova Cave, a natural refuge located in the Altai Mountains in southern Siberia. Scientists have been studying the oldest cave layers, which have so far failed to produce a single human fossil. A total of five human fossil fragments have been found: three belonging to Denisovans, one from Neanderthals, and one unrecognizable. The largest of these is no more than 1.6 inches (4 cm) long.
Remarkably, this tiny and precious pit of fossils was found amidst a jumble of 3,791 animal bone fragments. The researchers used a biomolecular method known as peptide fingerprinting to identify the bones, as it would not have been possible to do so through manual examination. The five bones contained collagen compatible with human peptide profiles (peptides are the building blocks of proteins), allowing identification (as a reminder, Denisovans and Neanderthals are humans).
“Finding a new human bone would be cool, but five?” Samantha Brown, a study co-author and small group leader at the University of Tübingen, said in the journal Max. Planck Institute statment.
Denisova Cave is a “remarkable place” when it comes to preserving DNA, said Deindo Masellani, a geneticist from the Max Planck Institute for Evolution. The team found enough DNA to reconstruct mitochondrial genomes, allowing them to confirm that the bones It belongs to Denisovans and Neanderthals paper Details of this discovery have been published in Nature Ecology & Evolution.
The layer containing Denisovan bones is approximately 200,000 years old. Previous Denisovans fossils are dated between 122,000 and 194,000 years ago, so they are now the oldest. The only Neanderthal bone has been dated between 130,000 and 150,000 years ago. The Altai Mountains “appear to have been an overlapping region of both Denisovan and Neanderthal groups for more than 150,000 years, attesting and possibly facilitating the population [interbreeding] In addition to preserving distinct hominin populations over such a long period,” according to the paper.
The three new Denisovans add to the six already discovered, including A finger bone From whom the DNA was extracted and a lower jaw Found in a cave on the Tibetan plateau – the first and only Denisovan fossil found outside Siberia. Denisovans were closely related to Neanderthals, and they interbred with modern humans before their extinction about 50,000 to 30,000 years ago. Traces of Denisovans DNA are found within the genomes of modern populations of Southeast Asia and Oceania.
As the scientists wrote in their study, a “wealth of archaeological materials” in the form of stone tools and animal remains were found within the Denisovan layer. It is the first time that archaeological evidence has been definitively linked to hominins, allowing new insights into their behaviour.
Interestingly, the style of restored stone tools, such as scrapers for working animal skins, cannot be matched with any known stone tradition. Denisovans lived near the Inui River and occupied caves during a warm period, hunting bison, deer, gazelle, antelope and woolly rhinoceros, in a lifestyle that lasted for thousands of years, the researchers noted.
These three Denisovans will likely yield more science in the coming years, as will Denisova Cave in general. Slowly but in a very methodical way, we are revealing more about these wonderful humans.