A partial cranium of Australopithecus sediba unearthed from a cave in South Africa.
Credit: AFP
MAROPENG, SOUTH AFRICA: Two skeletons of two-million-year-old hominids in South Africa have been dubbed a new species.
The partially fossilised specimens, of an adult female in her twenties or thirties and a boy aged between 11 and 13, were found in 2008 in a cavern 40 km from Johannesburg, South Africa. The new species was baptised Australopithecus sediba by its discoverers, who published their find in the journal Science.
"They, ladies and gentlemen, are potentially a Rosetta stone into the past," Lee Berger, a paleoanthropologist at the University of Witwatersrand, told a press conference at the Cradle of Humankind World Heritage Site.
But naming the find a new species has been criticised by other paleoanthropologists. Read "Hominid not new species, argue experts".
Between 195 and 1.78 million years old
"They represent a completely new and unexpected species of human ancestor to science. Something we did not think was there."
"We have been able date the Sediba fossils to between 1.95 and 1.78 million years ago," said Robyn Pickering from the School of Earth Sciences, University of Melbourne, in an associated paper in Science that dated the remains.
"This is the first time in South Africa, we have been able to achieve such good age control."
Could run like a human
The fossils are in "extraordinary condition", said Berger. "What we have found are arguably the most complete early hominid skeletons ever discovered."
The hominids walked upright and share a number of traits with the first known species of Homo sapiens, having long arms like apes but short and powerful hands.
They have evolved pelvises, small teeth and long legs that would enable them to run like a human. It is also probable that they could climb trees.
Shorter, lighter and with smaller brains
Both specimens were about 1.27 metres in height. The female weighed about 33 kg and the young male 27 kg.
The species had small brains, measuring about a third of the volume of those of modern humans.
But Berger noted that the shape of their brains appears to have evolved from other species of Australopithecus.
