In the Tam Ngu Hao 2 cave in Southeast Asian Laos, researchers have found a molar that they dated to be around 131,000 to 164,000 years old. Analysis of the proteins in the tooth and comparisons with other finds suggest that the tooth belonged to an early human of the genus Homo and probably came from a three-and-a-half to eight-and-a-half-year-old girl. According to the researchers, it was probably a Denisova. The discovery thus provides new insights into the spread of this early human species.
The existence of early humans on the Southeast Asian mainland has so far been proven primarily by finds of prehistoric stone tools and by individual early human remains. Which species of early humans lived in Southeast Asia at what time and possibly coexisted is largely unknown due to the scarce fossil finds. However, genetic analysis suggests that some Southeast Asian populations descended from Denisova people, a sister group to the Neanderthals whose remains were first discovered in Siberia’s Denisova Cave in the early 2000s. However, how widespread the Denisovans were in Asia is disputed.
No signs of wear
A new find suggests that the Denisova may have lived in Laos as early as around 150,000 years ago: In the limestone cave Tam Ngu Hao 2 in the Annamite Mountains in Laos, researchers have found a molar of a hominin surrounded by fossilized remains of animals such as rhinos , tapirs and sambar deer. A team led by Fabrice Demeter from the University of Copenhagen in Denmark analyzed this molar in detail and came to the conclusion that it probably came from a Denisova girl.
“The layer in which the fossil was found has been dated to be 164,000 to 131,000 years old,” the researchers report. “Studies of the structure of the tooth in conjunction with protein analyzes of the tooth enamel indicate that the tooth came from a young, probably female homo individual.” Since the molar tooth showed almost no signs of wear and its development apparently only shortly before After the death of the individual was completed, the researchers assume that the girl was between 3.5 and 8.5 years old when she died.
Neanderthal or Denisova?
To clarify which hominin species the tooth belongs to, the researchers compared its structure with other finds. “The tooth has a large crown and a complex occlusal surface that distinguishes it from the smaller, morphologically simpler teeth of Homo floresiensis, Homo luzonensis, and Homo sapiens,” they describe. On the other hand, many characteristics are similar to the teeth of Neanderthals and even the enamel analysis cannot rule out that it is a Neanderthal tooth. “In that case, it would be the southeasternmost Neanderthal fossil ever discovered,” write Demeter and his colleagues.
From their point of view, however, another hypothesis is more likely: “The tooth from Laos shows a clear resemblance to a specimen that was found in Xiahe in China and was assigned to Denisova,” they explain. “That makes membership in this sister group of the Neanderthals the most plausible hypothesis.” If the newly described specimen is actually a Denisova tooth, this sheds new light on the spread of these early humans. In 2019, researchers described a mandible found on a high plateau in Tibet that was likely also from a Denisova. “Taken together, the findings suggest that this early human population was able to adapt to very different environments,” the authors write. The discovery in Laos also indicates that the region was a hotspot for the genus Homo.
Source: Fabrice Demeter (University of Copenhagen, Denmark) et al., Nature Communications, doi: 10.1038/s41467-022-29923-z