Ancient girl’s tooth discovered in cave reveals mystery of Denisovans, sister species to modern humans

A close up of the tooth from a bird’s eye view. Credit: Fabrice Demeter (University of Copenhagen/CNRS Paris)

The Denisovans, a sister species to modern humans, inhabited Laos 164,000 to 131,000 years ago, with important implications for populations outside Africa and Australia.

What connects a finger bone and fossil teeth found in a cave in the remote Altai Mountains of Siberia to a single tooth found in a cave in the limestone landscapes of tropical Laos?

The answer to this question has been established by an international team of researchers from Laos, Europe, the United States and Australia.

The human tooth was discovered by chance during an archaeological survey in a remote region of Laos. Scientists have shown that it came from the same ancient human population first recognized in Denisova Cave (nicknamed the Denisovans), in the Altai Mountains of Siberia (Russia).

Sample TNH2 1 Tooth

Views of the TNH2-1 sample. Credit: Nature Communications

The research team made the major discovery during their 2018 excavation campaign in northern Laos. The new Tam Ngu Hao 2 Cave, also known as Cobra Cave, is located near the famous Tam Pà Ling Cave, where other important human (Homo sapiens) fossils dating back 70,000 years ago had previously been found.

The international team of scientists are convinced that the two ancient sites are linked to Denisovan occupations despite being thousands of miles apart.

Their findings were published in Nature Communicationled by University of Copenhagen (Denmark), CNRS (France), University of Illinois Urbanna-Champaign (USA), Ministry of Information, Culture and Tourism, Laos and supported by microarchaeological work undertaken at flinders university (Australia) and geochronological analyzes at Macquarie University and Southern Cross University in Australia.

What connects a finger bone and fossil teeth found in a cave in the remote Altai Mountains of Siberia to a single tooth found in a cave in the limestone landscapes of tropical Laos? The answer to this question has been established by an international team of researchers from Laos, Europe, the United States and Australia. Credit: Flinders University

Lead author and assistant professor of paleoanthropology at the University of Copenhagen, Fabrice Demeter, explains that the cave sediments contained teeth of giant herbivores, ancient elephants and rhinos known to live in forested environments.

“After all this work following the many clues written on fossils from very different geographical areas, our findings are significant,” says Professor Demeter.

“This fossil represents the earliest discovery of Denisovans in Southeast Asia and shows that the Denisovans were in the south at least as far as Laos. This is consistent with genetic evidence found in modern Southeast Asian populations. East.

View from Denisova Cave

A view from inside the Denisova Cave in the Altai Mountains in Russia. Note the very different vegetation and climate compared to Laos. Credit: Mike Morley, Flinders University

Following a very detailed analysis of the shape of this tooth, the research team identified many similarities to Denisovan teeth found on the Tibetan Plateau – the only other place where Denisovan fossils have ever been found.

This suggested that it was most likely a Denisovan who lived between 164,000 and 131,000 years ago in the hot tropics of northern Laos.

Associate Professor Mike Morley of Flinders University’s Microarchaeology Laboratory said the cave site named Tam Ngu Hao 2 (Cobra Cave) was discovered high in the limestone mountains containing the remains of an ancient cave sediment. cement filled with fossils.

Ngu Hao 2 Cave sediments in situ

Inside Ngu Hao Cave 2 showing the remaining concreted cave sediments adhering to the cave wall. The overlying whitish rock is a flow that caps the entire deposit. Credit: Fabrice Demeter (University of Copenhagen/CNRS Paris)

“We basically found the ‘irrefutable gun’ – this Denisovan tooth shows that they were once present as far south in the karst landscapes of Laos,” says Associate Professor Morley.

The complexity of the site created a challenge for the meetings and required two teams from Australia.

The Macquarie University team, led by Associate Professor Kira Westaway, provided the dating of cave sediments surrounding the fossils; and the Southern Cross University team led by Associate Professor Renaud Joannes-Boyau led the direct dating of the unearthed fossil remains.

“Establishing a sedimentary context for the final resting place of the fossils provides an internal check on the integrity of the find – whether the sediments and the fossils return a similar age, as seen at Tam Ngu Hao 2, then we know that the fossils weren’t buried long after the organism died,” says Associate Professor Kira Westaway.

A short video clip of Ngu Hao 2 (Cobra Cave) in northern Laos. The cave entrance is on the left. Credit: Fabrice Demeter (University of Copenhagen/CNRS Paris)

Direct dating of fossil remains is crucial to understanding the succession of events and species in the landscape.

“The good agreement of the different dating techniques, both on the sediment and on the fossils, attests to the quality of the chronology of the species in the region. And that has many implications for population mobility across the landscape,” says Professor A. Renaud Joannes-Boyau of Southern Cross University.

The fossils were likely scattered across the landscape when they were swept into the cave during a flood which deposited the sediments and fossils.

Unfortunately, unlike Denisova Cave, the humid conditions in Laos meant that the ancient[{” attribute=””>DNA was not preserved. However, the archaeological scientists did find ancient proteins suggesting the fossil was a young, likely female, human likely aged between 3.5 – 8.5 years old.

The finding suggests Southeast Asia was a hotspot of diversity for humans with at least five different species setting up camp at different times; H. erectus, the Denisovans/Neanderthals, H. floresiensis, H. luzonensis, and H. sapiens.

Southeast Asian caves could provide the next clue and further hard evidence to understand these complex demographic relationships.

Reference: “A Middle Pleistocene Denisovan molar from the Annamite Chain of northern Laos” by Fabrice Demeter, Clément Zanolli, Kira E. Westaway, Renaud Joannes-Boyau, Philippe Duringer, Mike W. Morley, Frido Welker, Patrick L. Rüther, Matthew M. Skinner, Hugh McColl, Charleen Gaunitz, Lasse Vinner, Tyler E. Dunn, Jesper V. Olsen, Martin Sikora, Jean-Luc Ponche, Eric Suzzoni, Sébastien Frangeul, Quentin Boesch, Pierre-Olivier Antoine, Lei Pan, Song Xing, Jian-Xin Zhao, Richard M. Bailey, Souliphane Boualaphane, Phonephanh Sichanthongtip, Daovee Sihanam, Elise Patole-Edoumba, Françoise Aubaile, Françoise Crozier, Nicolas Bourgon, Alexandra Zachwieja, Thonglith Luangkhoth, Viengkeo Souksavatdy, Thongsa Sayavongkhamdy, Enrico Cappellini, Anne-Marie Bacon, Jean-Jacques Hublin, Eske Willerslev and Laura Shackelford, 17 May 2022, Nature Communications.
DOI: 10.1038/s41467-022-29923-z

Leave a Reply

Your email address will not be published.