Friday, September 09, 2011

Australopithecus sediba

Australopithecus sediba at 1.977 Ma and Implications for the Origins of the Genus Homo. R. Pickering, et al. Science 333: 1421-1423.

Five papers based on Australopithecus sediba have been published in Science on Sept. 9, 2011. They include an analysis of the most complete hand ever described in an early hominin, the most complete undistorted pelvis ever discovered, the highest resolution and most accurate scan of an early human ancestors brain ever made, new pieces of the foot and ankle skeleton, and one of the most accurate dates ever achieved for an early hominin site in Africa.

Au. sediba (MH-1) skull reconstruction (opaque) with endocast (green, opaque) partially visible as a result of virtual craniotomy. Dr K. Carlson, U. Witwatersrand.
Abstract: Newly exposed cave sediments at the Malapa site include a flowstone layer capping the sedimentary unit containing the Australopithecus sediba fossils. Uranium-lead dating of the flowstone, combined with paleomagnetic and stratigraphic analysis of the flowstone and underlying sediments, provides a tightly constrained date of 1.977 ± 0.002 million years ago (Ma) for these fossils. This refined dating suggests that Au. sediba from Malapa predates the earliest uncontested evidence for Homo in Africa.

The cranium of the juvenile skeleton of Au.sediba. Pic courtesy of Lee Berger & U. Witwatersrand.