Forty-seven teeth from our species dated to 80,000-120,000 years ago have just been found in a cave in southern China, according to a new study that has many important implications concerning humanity’s early history.
The teeth, excavated from Fuyan Cave in Daoxian, southern China, represent the earliest unambiguous evidence for Homo sapiens outside of Africa.
"They are indeed the earliest Homo sapiens with fully modern morphologies outside of Africa," lead author Wu Liu of the Chinese Academy of Sciences told Discovery News. "At the Levant (much of the eastern Mediterranean), we also have human remains from the sites of Qafzeh and Skhul (in Israel) with similar ages, but these fossils have been described as retaining some primitive features and, thus, are not fully modern."
The remains are described in the latest issue of the journal Nature.
Well-dated and well-preserved fossils older than 45,000 years ago have been lacking outside of Africa, although primates themselves originated in Asia. Some researchers have even proposed an "Out of Asia" instead of "Out of Africa" migration path for the first Homo sapiens.
While the new findings do not resolve that question, they do reveal that our species was in southern China up to 70,000 years before it was in the eastern Mediterranean and Europe. The newly unearthed remains also offer evidence that China during the Pleistocene Era was likely inhabited by multiple groups of humans: our species and another more primitive lineage(s). Prior fossil discoveries show that the primitive Denisovans, for example, were in northern Asia.
Further complicating the mix is that Neanderthals were also living outside of Africa at the same time. The researchers suspect that the Neanderthals’ presence might have even deterred our species’ migration into Europe, since it took Homo sapiens so long to get there. Intriguingly, Neanderthals went extinct, or perhaps were absorbed into the Homo sapiens population, shortly after our species landed on what was Neanderthal turf.
"The coincidence between the arrival of H. sapiens to Europe and the Neanderthal extinction has often been interpreted as evidence of the superiority of modern humans, however, we now wonder that if modern humans were already present in southern China more than 80,000 years ago, why were they not capable of entering Europe until 45,000 ago?" co-author María Martinón-Torres of the National Center on Human Evolution in Burgos, Spain, asked.
"Maybe because Neanderthals were there," she continued, "it was not easy to take over 'their' land."
She further points out that Neanderthals were already in much lower numbers at the time of Homo sapiens’ European arrival -- Neanderthals often lived in more challenging environments with fewer resources.
The southern China cave where the teeth were found unfortunately provides no clues on what the culture of Homo sapiens was like there 80,000–120,000 years ago. No prehistoric tools or other telltale artifacts have been found so far at the site.
Senior author Xiu-jie Wu of the Chinese Academy of Sciences told Discovery News that she and her colleagues "do not think the cave was a living place. Future archaeological findings from this period in other Asian locations may shed some light about the type of culture or adaptations these humans had."
There is, however, very good news about the cave site, according to archaeologist Robin Dennell of the University of Exeter. He did not work on the project, but wrote a separate News & Views article, also published in Nature, about the discovery.
He explained that a flowstone layer covers the entire cave floor and has a minimum age of 80,000 years old. The teeth were found in a sandy clay layer well beneath the stone, which allowed them to be reliably dated.
Dennell wrote that most researchers believe our species first appeared in East Africa around 190,000 to 160,000 years ago, and subsequently dispersed into the eastern Mediterranean several thousand years later. Since the prevailing theory holds that Homo sapiens originated in or near the tropics, he thinks it makes sense that our early ancestors would have initially dispersed eastward rather than northward, where winter temperatures rapidly then fell below freezing.
Read more at Discovery News
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