An ancient molar discovered in today’s Laos was attributed to a Denisovan little girl

Views of the molar TNH2-1
Views of the molar TNH2-1

An article published in the journal “Nature Communications” reports the discovery in today’s Laos of a tooth that was attributed to a little girl that belonged to the Denisovan species, an archaic human species still mysterious in many ways. The molar was dated between 164,000 and 131,000 years ago from the analysis of the sediments in which it was found in the Cobra Cave (Tam Ngu Hao 2), in the Annamite Chain, in Laos. The warm and humid conditions in that area offer little hope of still finding pieces of DNA but the proteins and appearance of the molar, very similar to that of a jawbone discovered in Tibet and attributed to a Denisovan, led the researchers to that conclusion.

So far, the only physical evidence related to the Denisovans were the few bones found in Siberia and a jawbone discovered in Tibet. However, the DNA obtained from the Siberian bones made it possible to discover that these archaic humans interbred with Homo sapiens because many of their genes were inherited by modern humans, especially by Asian populations.

The molar subject of this new study, cataloged as TNH2-1 (Image courtesy Demeter, F., Zanolli, C., Westaway, K.E. et al. All rights reserved), was discovered during a search that began after ancient human remains were found in a cave in the same mountain area. The cave conditions are adverse to DNA conservation but there are proteins that are much more resistant to hot and humid conditions and can be preserved for extremely long times. That’s a nice help in cases of fragmentary fossils, common in the field of paleontology, because proteins can provide some clues as to the species to which the fossil belongs.

The examination of proteins obtained from the molar TNH2-1 indicates that the specimen was a female belonging to a species related to Homo sapiens. The roots show a maturation stage compatible with that of a girl between 3.5 and 8.5 years of age at the time of death according to criteria typical of modern humans. The dating is indirect, conducted by examining the sediments in which it was found, and indicates that the girl lived between 164,000 and 131,000 years ago.

The possibility of attributing bones and teeth of ancient humans to a particular species generally passes through a morphological analysis because in most cases it’s not possible to obtain DNA. The molar discovered in the Cobra Cave resembles those of the jawbone discovered in Tibet. Its characteristics also have similarities with those of Neanderthal molars but no trace of that species has ever been discovered so far east while the Denisovans left genetic traces even in Filipino populations.

Each new fossil attributed to the Denisovans can offer valuable information on this human species that is still in many ways mysterious. We literally don’t know what they looked like as no complete or nearly complete skulls have been attributed to Denisovans. The discoveries of fossils linked to archaic human species show the complex history of humanity and the difficulties in attributing various fossils. In the case of the Denisovans, new discoveries and new studies may also help to understand whether they have become extinct or they interbred with Homo sapiens so frequently that they disappeared as a separate species.

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