New hominid species discovered and described in South Africa

A team led by Professor Lee Berger, a renowned palaeoanthropologist from the University of the Witwatersrand, Johannesburg (aka Wits University) have described and named a new species of hominid, Australopithecus sediba, almost two million years old, which was discovered in the Cradle of Humankind World Heritage Site, 40 kilometres out of Johannesburg, South Africa. Two papers related to this find, authored by Prof. Lee Berger and Prof. Paul Dirks respectively, will be published in the journal Science on Friday, 9 April 2010.

"Sediba, which means natural spring, fountain or wellspring in Sotho, one of the 11 official languages of South Africa, was deemed an appropriate name for a species that might be the point from which the genus Homo arises," comments Berger. "I believe that this is a good candidate for being the transitional species between the southern African ape-man Australopithecus africanus (like the Taung Child and Mrs. Ples) and either Homo habilis or even a direct ancestor of Homo erectus (like Turkana Boy, Java man or Peking man)."

The fossils, a juvenile male and an adult female, were deposited within a single debris flow and occur together in a near articulated state in the remains of a deeply eroded cave system. The sedimentary and geological context indicates that the timing of their death was closely related and occurred shortly before the debris flow carried them to their place of burial.

The species has long arms, like an ape, short powerful hands, a very advanced pelvis (hip bone) and long legs capable of striding and possibly running like a human. It is likely that they could have climbed. "It is estimated that they were both about 1.27 metres, although the child would certainly have grown taller. The female probably weighed about 33 kilograms and the child about 27 kilograms at the time of his death," adds Prof. Berger. "The brain size of the juvenile was between 420 and 450 cubic centimetres, which is small (when compared to the human brain of about 1200 to 1600 cubic centimetres) but the shape of the brain seems to be more advanced than that of australopithecines."

Through a combination of faunal, U-Pb and palaeomagnetic dating techniques, the age of the rocks encasing the fossils has been determined at 1.95-1.78 Ma. . Cosmogenic dating was used to interpret the landscape formation and to determine the depth of the cave at the time.

The skeletons were found amongst the articulated skeletons of a sabre-toothed cat, antelope, mice and rabbits. They are preserved in a hard, concrete like substance known as calcified clastic sediment that formed at the bottom of what appears to be a shallow underground lake or pool that was possibly about 50 metres tall about 1,9 million years ago.

Fossil preparators have worked arduously over the last two years to extract the bones from the rock. About 60 leading scientists from around the world and tens of students have had the opportunity to work on these amazing fossils. The most sophisticated scanning technology has been used to unveil the secrets of the past.

The site continues to be explored and without a doubt there are more groundbreaking discoveries to come forth. In celebration of this find, the children of South Africa have been invited to develop a common name for the juvenile skeleton. The fossils are owned by the people of South Africa, and curated by the University of the Witwatersrand, Johannesburg.

Source: University of the Witwatersrand