The mysterious human species named Homo naledi, which was first announced just two years ago, likely lived alongside Homo sapiens or modern humans, new research has revealed.
Homo naledi was alive sometime between 335,000 and 236,000 thousand years ago, according to the study that analysed the naledi remains first discovered inside the Dinaledi chamber, part of South Africa's Rising Star cave system.
The research, published in three papers in the journal eLife, presents the long-awaited age of the naledi fossils from the Dinaledi chamber and also announces the new discovery of a second chamber in the Rising Star cave system, containing additional specimens of Homo naledi.
These include a child and a partial skeleton of an adult male with a remarkably well preserved skull.
The discovery of a second chamber lends support to the controversial hypothesis that Homo naledi deliberately disposed off its dead in these remote, hard to reach caverns.
The new discovery and research was done by a large team of researchers from the University of the Witwatersrand (Wits) in South Africa, James Cook University in Australia, the University of Wisconsin, Madison in the US, and more than 30 additional international institutions.
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After the description of the new species in 2015, experts had predicted that the fossils should be around the age of earliest known fossil members of our genus, such as Homo rudolfensis and Homo habilis, species that lived nearly two million years ago.
But the new research suggests that the fossils from the Dinaledi chamber are barely more than one-tenth that age.
"The dating of naledi was extremely challenging," said Professor Paul Dirks of James Cook University.
"Eventually, six independent dating methods allowed us to constrain the age of this population of Homo naledi to a period known as the late Middle Pleistocene," Dirks said.
The age for this population of hominins shows that Homo naledi may have survived for as long as two million years alongside other species of hominins in Africa.
At such a young age, in a period known as the late Middle Pleistocene, it was previously thought that only Homo sapiens (modern humans) existed in Africa.
More critically, it is precisely this time period that gave rise to what has been called "modern human behaviour" in southern Africa - behaviour attributed, until now, to the rise of modern humans and thought to represent the origins of complex modern human activities such as burial of the dead, self-adornment and complex tools.
The researchers noted that the discovery would have a significant impact on our interpretation of archaeological assemblages and understanding which species made them.
"We can no longer assume that we know which species made which tools, or even assume that it was modern humans that were the innovators of some of these critical technological and behavioural breakthroughs in the archaeological record of Africa," Professor Lee Berger of the University of the Witwatersrand said.
"If there is one other species out there that shared the world with 'modern humans' in Africa, it is very likely there are others. We just need to find them," Berger added.
--IANS
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