Australopithecus sediba – new analyses and surprises

Australopithecus sediba – new analyses and surprises

A different way of walking upright

New studies of the skeletons of Australopithecus sediba suggest that this South African species has a surprising combination of features that may make it an ancestor of the human genus Homo.

Dated 1.98 million years old, the fossil skeletons of A. sediba from Malapa cave are so complete that scientists can see what entire skeletons looked like near the time when Homo evolved. Details of the teeth, the length of the arms and legs, and the narrow upper chest resemble earlier Australopithecus, while other tooth traits and the broad lower chest resemble humans.

What is surprising is that the legs and feet point to a previously unknown way of walking upright. With each step, Australopithecus sediba turned its foot inward with its weight focused on the outer edge of the foot. This odd way of striding may mean that upright walking evolved on more than one path during human evolution.

The Malapa scientific team, led by Dr. Lee Berger, published its new studies on April 12, 2013, in the journal Science.

photo of replica of Australopithecus sediba adult female, MH2

Berger, L.R., 2013. The mosaic nature of Australopithecus sediba. Science Vol. 340 no. 6129, pp. 163-165. (DOI: 10.1126/science.340.6129.163)