Our Kind of Hominins

The classic excavations at the Swartkrans cave locality, South Africa, have yielded a large number of hominin specimens, attributed mostly to Praeanthropus robustus . One of these, SK 54, is a young child with two very distinct puncture marks on its cranium. Kenyanthropus platyops originates from geological deposits dating to around 3.5 million years ago. Its discovery so recently, with its unique anatomical features so unexpected, sent shockwaves through the anthropological world and started a flurry of speculation. Indeed, recently it has been suggested that the cranium of the type specimen of Kenyanthropus platyops (specimen KNM-WT 40000) may actually represent a specimen of Praeanthropus , as it suggests that the distortion of the specimen has resulted in a misdiagnosis. While this suggestion deserves serious consideration, some derived features of Kenyanthropus, which are unlikely to be overtly influenced by the type of distortion, suggest otherwise. For example, K. platyops , unlike Pr. afarensis , does not have an occipitomarginal sinus or a compound temporonuchal crest; it has reduced incisor heteromorphy, the upper molars are also significantly reduced in size relative to Praeanthropus , and finally its enamel thickness is reduced. Therefore, Kenyanthropus can be recognized as a distinct taxon.