COLLEGE STATION, April 8, 2010 - Two well-preserved skeletons of a human ancestor never before seen have been discovered in South Africa by a team that includes a Texas A&M University anthropologist.
The discovery is outlined in a paper titled " Australopithecus sediba : A New Species of Homo -like Australopith from South Africa," which is the cover story of the April 9 edition of "Science Magazine," the official publication of the American Association for the Advancement of Science (AAAS). The lead author on the paper is the project director, Dr. Lee Berger of the University of the Witwatersrand. Darryl de Ruiter of Texas A&M, the lead craniodental specialist on the project, is the second author.
The genus name Australopithecus translates into "southern ape," and the species is loosely referred to as an "ape man," because they could still move around in the trees but once on the ground could walk on two legs as humans do, de Ruiter explains. " Sediba " means "fountain" or "wellspring" in the Seotho language.
"We actually think we have found the best candidate for a direct ancestor of Homo , the genus to which humans belong," de Ruiter said of the fossils, which are believed to be between 1.78 and 1.95 million years old.
The site of the remains - a 10-by-10-foot cave about 8 feet deep - was discovered in August 2008, de Ruiter said. It was actually Berger's 9-year-old son who spotted the first bone.
"When I first saw the skeletons, I knew we had something special," said de Ruiter, who examined the skull, jaws and teeth of what is believed to be an adult female and a juvenile male - possibly members of the same group. "Both were remarkably complete and extremely well-preserved."
He said the skulls are human-like but smaller, and their teeth are similar to humans'.
The skeletons are shaped like those of early representatives of Homo , though they are relatively small like those of the australopithecines , the ancestors of Homo . Conversely, the teeth of the new species are small like in humans, but shaped like those of Australopiths . "What we have here is a clearly transitional form," de Ruiter stated.
Only three other skeletons of this great antiquity in Africa approach this level of completeness, de Ruiter says: the 2.9-million-year-old "Lucy" from Ethiopia, the 2.2-million-year-old "Little Foot" from elsewhere in South Africa and the 1.6-million-year-old "Nariokotome Boy" in Kenya. However, this new site is unique in revealing multiple individual skeletons that can be directly associated with each other, de Ruiter says.
The team is continuing to search for additional skeletons at the site. De Ruiter said he and some of his students are returning to the South African site this summer. Meanwhile, a contest is planned to allow South African schoolchildren to nickname the two skeletons.