The first humans were still swinging from the trees two million years ago, according to scientists, after confirming that a set of contentious fossils represents a "missing link" in the family tree of humanity.
Fossils of Australopithecus sediba have fueled scientific debate since they were found at the Malapa fossil site in South Africa 10 years ago.
And now, researchers have established that they are closely linked to the genus Homo, which represents a kind of bridge between primitive humans and their predecessors, demonstrating that primitive humans still swayed from trees 2 million years ago.
The site of Malapa, the "Cradle of humanity" of South Africa, was famous for an accident discovered by nine-year-old Matthew Berger when he was chasing his dog.
That stroke of luck eventually led to this week's find, detailed in the magazine "Paleoanthropology."
The findings help fill a gap in the history of humanity, slipping between the famous skeleton of "Lucy" 3 million years ago and the "skillful man" Homo habilis, who was discovered to be using tools between 1.5 and 2 , 1 million years. .
They show that the primitive humans of the period "spent significant time climbing the trees, perhaps to forage and protect themselves from predators," according to the study in the magazine "Paleoanthropology."
"This larger picture sheds light on A. sediba ways of life and also on an important transition in the evolution of hominins," said lead researcher Scott Williams of the University of New York.
"There is still a lot to discover"
Two partial australopital skeletons, a man and a woman, were found in 2008 in a cave collapsed in Malapa, in the "Cradle of Humanity" of South Africa.
"Australopithecus" means "southern ape," a genus of hominids that lived about 2 million years ago.
Their discovery sparked years of debate in the scientific community, some rejected the idea that they were of a species that had not been previously discovered and that they had close links to the genus homo, and others floated the idea that they were from two different species .
But the new research has put aside those suggestions and has described "numerous characteristics" that the skeletons share with fossils of the genus homo.
The hands and feet of Australopithecus sediba, for example, show that he spent a good amount of time climbing trees. The hands have grip capabilities, which are more advanced than those of Homo habilis, suggesting that he was also one of the first users of the tool.
The researchers of the article highlighted the extraordinary story of how the fossils were found, and pointed out that other dramatic tracks in the history of mankind still hope to see the light of day.
"The first fossil of au. "Sediba was discovered by Matthew Berger, then a nine-year-old boy, who stopped and examined the rock with which he stumbled as he followed his dog Tau away from the well of Malapa," they wrote.
"Imagine for a moment that Matthew stumbled over the rock and continued to follow his dog without noticing the fossil," they added.
"If those events had happened, our science would not know about Au. sediba, but those fossils would still be there, still encased in calcified clastic sediments, still waiting to be discovered. "
"The fortuitous discovery of Malapa fossils and other equally incidental recent findings should be a reminder to all that there is still much to discover about our evolutionary past," the authors concluded.