Denisovans are diverse (Introduction)

by David Turell , Wednesday, May 01, 2019, 21:32 (1832 days ago) @ David Turell

Found not only in the Siberian cave but also in Tibet!:

https://www.newscientist.com/article/mg24232283-700-major-discovery-suggests-denisovans...

"THE first fossil of our cousins the Denisovans ever to be discovered outside Siberia has been identified in Tibet. It hints that fossils from these extinct humans are more widespread than we thought, and may help settle a long-running debate about our origins.

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"He and his colleagues examined a jawbone discovered in 1980 in Baishiya Karst cave, in Tibet’s Jiangla river valley. They found that the shape of the jaw and large size of the teeth are different to those of modern humans.

"Radioisotope dating suggested that the fossil is 160,000 years old at least, which is tens of thousands of years before our own species is thought to have reached the Tibetan Plateau.

"No DNA could be extracted from the fossil, but analysing collagen protein in its teeth confirmed the jawbone came from a Denisovan, because modern humans and our other extinct cousins the Neanderthals have different genes for collagen

"The finding could explain the 30,000-year-old stone tools discovered in Tibet last year. It is mind-blowing that hominins could have been living in such an extreme environment, says Hublin. “Even today, Tibet is not an easy place to live. There aren’t many resources and there’s a lack of oxygen.”

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"Hublin says several previously discovered fossils from sites in China have features that don’t match those of modern humans or Homo erectus, another ancient hominin which is, like the Denisovans and Neanderthals, thought to have left Africa long before we did.
“I predict that most of the Chinese hominin fossil record younger than 350,000 years and older than 50,000 is made of Denisovans,” says Hublin.

“'We probably have lots of Denisovan remains sitting in museums all over the world, but they have different names on them,” says Cox.

"If Hublin is right, these fossils could help settle the debate over whether our ancestors evolved solely in Africa, or whether important steps took place in Asia too. Previous discoveries of fossils in China have been interpreted by some as intermediate species between H. erectus and modern humans, suggesting that we evolved in eastern Asia. But this idea will lose ground if the fossils turn out to be Denisovan.

"However, Sheela Athreya at Texas A&M University says that linking such fossils to Denisovans would be putting the cart before the horse. We know so little about the Denisovans’ physical characteristics and where and when they lived, she says. “We don’t know what ‘Denisovan’ is.'”

Comment: There is lots more we need to learn about this group of early homos. It must be recognized that the fossils we study are not in large enough numbers to get a clear picture of our evolution.