Fig. 5

Early hominins from South Africa. a A. africanus from Sterkfontein. b P. robustus from Swartkrans. The sites from which these fossils are found are approximately only a mile from each other. A. africanus, a gracile australopith, predates P. robustus, a robust australopith. Note the more massive cheekbones and the sagittal crest (a ridge of bone on the braincase from which large chewing muscles arise) in P. robustus. Image and copyright courtesy of Eric Delson