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If you have been on the up and upon the most recent goings-on in paleoanthropology and human evolution, by the way, evidence points these days, is that up until as recently as 70 kya; we were living amongst as many as six species of humans. From the well-known Neanderthals, found in western Europe into the deserts of the Middle East, to the Hobbits on
the island of Flores. Being the only bipedal ape on this planet is something relatively new. As we explored in my recent paper titled “Planet of the Apes”, you can read here which goes into much more detail on this subject. For today’s topic, however, we are going to be talking about one specific group, or population of ancient peoples, commonly known as the Denisovans.
The Denisovans are an enigmatic people, while not designated as an official species just yet, due to a lack of physical evidence, we have a wealth of knowledge about them from their DNA. For you see, back in 2008, in the Altai Mountains of Siberia, in a well-known archaeological site known as Denisova Cave, a tiny portion of a pinky bone was found. It would turn out that this pinky bone belongs to an ancient little girl, dating to around 75 kya. But there would be something extra special about this little girl, she was from a species previously unknown to science.
Amazingly, from this small piece of bone, scientists at the Max Planck Institute for Evolutionary Sciences were able to gain a piece of DNA that contained around 70% of the entire Denisovan genome. This was more than the entire yield of Neanderthal DNA yield that researchers at the Max Planck had at the time. We would learn a great deal about these people from their DNA, but we would go a long time without finding any more fossils that we could contribute to them. While there is some speculation, that certain skulls such as the Harbin, or “Dragon Man” skull may actually belong to Denisovans, without DNA, we cannot know for sure.
Discovered some forty years ago, but only recently handed over to scientists, was a mandible found from a high Tibetan plateau, which had giant, almost nonhuman molars. DNA would show that this would be the first Denisovan fossil outside of Denisova Cave. It also showed how wide the range of these people could have been. But now, a new find is showing just how far that range could have been, with physical evidence. We know from the DNA that many people of Asian, and South Asian descent, as well as aboriginal Australians, have up to 7% of Denisovan DNA. This has to be explained by some introgression into the modern populations of Homo sapiens.
Now, however, a new find from Laos, in the Tam Gnu Hao 2, or Cobra Cave, a singular, small tooth was found and reported this last week. Dating to the middle Pleistocene, or 164-131 kya with the use of luminescence dating on the sedimentary matrix. These places the tooth well within the region of Densivoans who could have lived here at the time. According to the researchers, “Analyses of the internal structure of the molar in tandem with palaeoproteomic analyses of the enamel indicate that the tooth derives from a young, likely female, Homo individual. The close morphological affinities with the Xiahe specimen from China indicate that they belong to the same taxon and that Tam Ngu Hao 2 most likely represents a Denisovan.”
So what does this mean? Well, it means that Denisovans were covering a great deal of ground, and were doing it up until somewhat recently. While there are three groups or populations of Denisovans that are known to science at this time, and we do not know which this belongs to, we know that this tooth, which again belonged to a small girl, is going to shed a great deal of light on the presence of Denisovans, and other early humans in Southeastern Asia.
As always, with more answers, and more information that we get, we are just led to more questions, but that is what makes science great! There is always more to learn, and if you keep at it, you will always be finding answers!
Did you learn something about the Denisovans today? Are you surprised that they have been found so far south when compared to their close Neanderthal kin?
Original Paper:
World of Paleoanthropology 