Fossils Propose Potential New Candidate For Human Ancestor
A collection of prehuman skeletons discovered in South Africa reveals that these creatures were, from head to heel, a collage of primitive and modern anatomy, and anthropologists say it may be time to reconsider mankind's evolutionary path.
Several partial skeletons of the two million-year-old species Australopithecus sediba were discovered in South Africa in 2008 at Malapa, near Johannesburg, South Africa. The human branch of the evolutionary tree, called Homo, is thought to have arisen from a group of ancient species called australopithecines. The newly studied species is a member of this group, and so its similarities to humans are interesting and may solve the mystery as to how Homo sapiens emerged.
In six research papers published in Science, an international team described how the hominids had almost-human hands attached to apelike arms, a rib cage that was narrow like an ape's at the top but more humanlike lower down, and a spine that likely had the same number of vertebrae as a human.
Jeremy DeSilva of Boston University, lead author of one of the papers, said the fossils reveal an unexpected "mosaic of anatomies."
"I didn't think you could have this combination that hand with that pelvis with that foot... And yet, there it is," he noted.
The research, led by Lee Berger of South Africa's University of the Witwatersrand, includes the forensic autopsy of the sediba species that apparently fell to their deaths in the Malapa Cave about 1.97 million years ago. No one knows if they died together or alone. There is no evidence the creatures were killed by animals.
"All of the research so far shows that sediba had a mosaic of primitive traits and newer traits that suggest it was a bridge between earlier australopiths and the first humans," said Professor Debbie Guatelli-Steinberg, one of the study authors from Ohio State University in the US.
Australopithecus sediba is in the same genus family as two other ancient hominins discovered in Africa, Australopithecus afarensis - the famous "Lucy" skeleton unearthed in Ethiopia in 1974 - and Australopithecus africanus, also from South Africa.