A newly published scientific paper concludes partial skulls discovered in China provide evidence of a "hybrid" human who lived some 100,000 years ago.
The fossil find spotlighted in Science magazine, a publication of the American Association for the Advancement of Science, is "up-ending ideas about human evolution," reported News.com.au.
The skulls discovered in Xuchang, in central China, "appear to be hybrids of humans, Neanderthals – and a third race."
The report said the integral characteristics are human because of "the large brain capacity, lightly built cranial vaults and modest bone rides on the brow, similar to early modern humans." Further, there are features similar to humans from the Middle Pleistocene period, and they have inner ear structures like Eurasian Neanderthals.
Science magazine speculated that finger and other bone fragments, including fragments making up mostly of two skulls, come from "Denisovan," a subspecies of human.
Palaeoanthropologist Maria Martinon-Torres said the skulls "definitely fit expectations about Denisovans," which she described as having "an Asian flavor but closely related to Neanderthals."
"What few Denisovan remains have been found have dated from 100,000 to 50,000 years ago. Their DNA paints a picture of a species isolated for hundreds of thousands of years before mixing with Neanderthals and modern humans," she said.
"This is exactly what the DNA tells us when one tries to make sense of the Denisova discoveries," palaeoanthropologist Jean-Jacques Hublin of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, told News.com.au.
"These Chinese fossils are in the right place at the right time, with the right features."
However, anthropologist Erik Trinkaus, a professor at Washington University in St. Louis, says hybrid isn't the right description.
"I don't like to think of these fossils as those of hybrids," he told the publication. "Hybridization implies that all of these groups were separate and discrete, only occasionally interacting. What these fossils show is that these groups were basically not separate.
"The idea that there were separate lineages in different parts of the world is increasingly contradicted by the evidence we are unearthing," he said.
David Menton, who was an award-winning professor at Washington University's School of Medicine for 34 years and holds a Ph.D. in biology from Brown, believes Trinkaus has it right.
"I would only add that these groups were all fully human Homo sapiens. A Homo sapien's egg cannot be fertilized by any non Homo sapiens sperm that we know of," he said.
The bottom line, he said, is that there are wide variations in humans, but they are all humans.
Menton, who retired as an associate professor emeritus and now contributes to Answers in Genesis, which runs the Creation Museum and has built a life-size version of Noah's Ark, says that as more discoveries are made, it's increasingly clear that there's only one human race.
The evidence, he said, points to a common ancestry.
"These fossils, these groups were basically not separate,"Â Menton told WND. "They were humans."
He pointed out that artifacts reveal they made bracelets out of translucent minerals, drilling holes "with a high-speed drill."
The News.com.au report said fragments of two skulls were found in Xuchang in 2007 and 2014, and they date to about 150,000 years ago.
The report notes that "the fossil record for the time is relative scarce."
But there are finds that suggest the existence of "Peking man," "the unexplained Dmanisi hominins" and "the strange Denisovans."
The report said the evidence is causing confusion, since populations apparently did not live "largely independent of each other."
The finds raise questions about the "out of Africa" assumptions regarding mankind's residency on earth.
"We don’t know how tall it was. We don't know if it was well-built, like a Neanderthal, or more delicate – like a Denisovan. Nor has any portion of the face – including a jawbone – yet been found. This means we don’t even know what they looked like," the report said.
What is known is that the brain cavity was at least the size of today's humans, who vary widely in physical characteristics around the world.