Archaeologists working in a cave in Laos have discovered a molar that may belong to a member of the extinct hominin species known as Denisovans.
The tooth was discovered in 2018 in the Tam Ngu Hao 2 cave, also known as Cobra Cave, in Huà Pan province, Laos. Analysis indicates that it belonged to a young female individual, aged from 3.5 to 8.5 years old. The molar has been dated to between 164,000 and 131,000 years ago using the sediment in which it was found and associated faunal material, making this the first example of an unambiguous specimen from the Homo genus dating to the Middle Pleistocene ever discovered in mainland south-east Asia.
Unfortunately, the hot and humid conditions in Laos made it impossible to extract DNA from the tooth. However, researchers were able to use morphological analysis to find out more about the specimen. They compared the tooth to molars from other hominins including Homo sapiens, Neanderthals, and Homo erectus, and determined that it was most likely to belong to a Denisovan, as it displays a combination of Neanderthal-like and Homo erectus-like features, and is very similar to a specimen from Xiahe in China that is also believed to be Denisovan.
The Denisovans were first identified in 2010 in Denisova Cave in Siberia; genetic analysis of material from these fossils revealed that Denisovans were more closely related to Neanderthals than to modern humans, but they are known to have interbred with other human species including Neanderthals and Homo sapiens. Denisovan DNA has been found in modern populations in the Philippines, Australia, and Papua New Guinea, but the geographic range of Denisovans in the past remains uncertain, as only a few fossils have been found so far.
The molar found in Tam Ngu Hao 2 cave supports the idea that Denisovans were living in south-east Asia in the Middle Pleistocene, significantly expanding the known range of the species, and indicating that they were able to adapt to very varied environments. Researchers hope that this discovery will prompt further archaeological work that could improve our understanding of this mysterious branch of our family tree and the story of evolution in south-east Asia.
The results of the excavation and analysis have been published in Nature Communications (https://doi.org/10.1038/s41467-022-29923-z).