Australopithecus sediba is being cautiously examined as a possible missing link in the development of the human species. When a 9-year-old boy found some unusual bones near the Cradle of Humankind site near Johannesburg, South Africa in 2008, a further investigation led to a cave that held the almost two million year old fossils of an adolescent male and an adult female A. sediba. Some of the findings were published in Friday’s issue of the journal Science.
Since then, an international team of scientists has been hard at work to figure out where the species fits on the family tree.
Australopithecus sediba is smaller than our species, Homo sapiens, and it has an average smaller brain. The adult female wasn’t much taller than four feet, and she probably weighed around 72 pounds. The young male’s brain was 450 cubic centimeters or smaller, compared to a human brain that could reach around 1,600 cubic centimeters.
Their disproportionately long arms and legs reminded University of California at Santa Cruz researcher Daniel Farber of an orangutan. Overall, the species does seem to be an odd mix of human and apelike characteristics.
Their advanced hips and pelvis, combined with their long legs, suggested to researchers that the species could easily walk upright for long distances, rather than simply swing from the trees.
Lee Berger, of South Africa’s University of Witwatersrand and the lead author of the study, is convinced that A. sedabis possesses so many human-like traits that, “across the whole of the body that it must be considered, at the very least, a possible [human] ancestor.”
A reconstruction of the female’s gait suggested that she had a naturally pigeon-toed, somewhat shrugged-shoulder walk. Boston University’s Jeremy DeSilva, one of the researchers, admitted that he’d tried to walk that way himself, and it’s pretty painful.
However, the team observed features in the Australopithecus sediba bones that made the gait easy and natural for them.