Prehistoric tooth reveals surprising details about long-lost human 'cousins'

Prehistoric tooth excavated from the Denisova cave in Siberia's Altai Mountains in 2010 (Dr. Bence Viola, Max-Planck-Institute of Evolutionary Anthropology)

A prehistoric tooth discovered in a remote Russian cave has helped experts unearth surprising details about a group of long-lost human relatives called Denisovans.

The tooth was excavated from the Denisova cave in Siberia’s Altai Mountains in 2010 and extensively analyzed. Experts have now released their findings, which show that Denisovans were around much earlier than previously thought.

A piece of Denisovan finger bone and another tooth discovered in the same cave, respectively, in 2010 and 2000, had been dated to between 50,000 and 70,000 years ago. “The new tooth is 50,000 years older than the others – this is really interesting, it shows us these guys were around for a long time,” Bence Viola, an assistant professor at the University of Toronto’s Department of Anthropology, told FoxNews.com.

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The finger bone and the earlier tooth were from individuals that lived within a timespan of about 1,000 years each other, according to Viola.

The anthropologist, who worked on the research with experts from the Max Planck Institute in Germany, described Denisovans as our “long-lost cousins” who lived at the same time as both humans and Neanderthals.

“We know that they interbred with Neanderthals and modern humans,” he said, noting small amounts of Denisovan DNA in modern-day Melanesians who inhabit a number of Pacific Ocean islands. “At some point the ancestors of present-day Melanesians met Denisovans – we think that the Denisovans were widespread across all of Asia.”

The anthropologist also noted a key difference in Denisovans’ appearance compared to humans. “Based on the tooth, they had very large teeth,” he said. “[The tooth] is wide and long – it’s about double the surface of a modern human tooth.”

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Both teeth discovered were upper molars.

Experts are also intrigued by the genetic makeup of the Denisovans. “These Denisovans who were all found have twice as much genetic diversity as Neanderthals and close to as much genetic diversity as we see in modern humans, which is pretty surprising,” Viola said.

Anthropologists, however, are still uncertain about when Denisovans became extinct. “They clearly were around when the first humans arrived in South East Asia about 50,000 years ago because they interbred with them,” explained Viola. “But we’re not really sure when extinction occurred.”

The findings were released in the Proceedings of the National Academy of Sciences.

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