A team of scientists has uncovered the skeletal remains of an unknown species of ancient human, it was revealed today.
The researchers suggest the species - named Australopithecus sediba - could be a direct ancestor to Homo erectus, the predecessor of modern humans.
The two partial articulated skeletons of an adult female and child were found in miners’ debris in South Africa in the Cradle of Humankind World Heritage Site in 2008 by Professor Lee Berger from South Africa’s University of the Witwatersrand.
The fossils were dated as being around 1.95 million years old, placing the species at a transition point in our evolutionary story from small brained bipedal apes to larger brained human ancestors.
Professor Paul Dirks, head of the School of Environmental Sciences at James Cook University, Australia, led the team which described the geological setting and age of the remains.
He said paleomagnetic analysis of the debris encasing the fossils had helped define their age.
“These ages coincide with the period in which the species of the genus Australopithecus are gradually being replaced by species of the genus Homo, of which we, Homo sapiens are part,” he said.
Dr Robyn Pickering from the School of Earth Sciences at the University of Melbourne, Australia, was part of the team which aged the fossils.
“It has never been clear where our own genus Homo came from - this new discovery Australopithecus sediba could answer these questions,” she said. “Knowing how old these early human (hominin) fossils are is critical to our knowledge of where this newly found species fits into our family tree. Now we are able to fill in the gap of what happened two million years ago in the beginnings of our species.”
However, some scientists today poured scorn on claims that the remains were those of a new species of human ancestor. They hailed the discovery of the skeletal remains of an infant and adult female, unearthed in a South African quarry, as “truly amazing” - but denied they were a missing link.
Dr Darren Curnoe, specialist in human evolution at the University of New South Wales, Australia, said claims that these new fossils represent an ancestor of living humans is misleading.
“Australopithecus sediba is the wrong species, in the wrong place, and at the wrong time. It is way too primitive to be the ancestor of the human genus Homo, one of our direct ancestors,” he said.
“For a start, fossil Homo is known from East Africa to be almost half-a-million years older. The skull, tooth and limb bone anatomy of the older Homo also looks very different from those of sediba. Finally, a number of key
skulls compared to the new sediba remains have been incorrectly described, leading to false conclusions about its place in human evolution.”
Two papers describing the discovery and dating procedures will be published in the journal Science.