Editor's Summary

9 August 2007

Head to head

The hominin species Homo habilis and the generally larger and later Homo erectus are often regarded as two points on a single evolutionary lineage, separated only by time. The case for that view was strengthened by the interpretation of the small, primitive skulls from Dmanisi in Georgia as morphological intermediates. But new fossil discoveries tell a different story. A particularly small Homo erectus skull, and jaw material from a late-surviving specimen of Homo habilis, were found in contexts that suggest that the two species coexisted in the Lake Turkana basin in Kenya for almost half a million years. As well as overlapping in time, H. habilis and H. erectus overlapped in size as well. A high degree of sexual dimorphism in H. erectus may be a factor in this. The cover shows the new Homo erectus fossil, a partial skull known as KNM-ER 42700, together with the largest African H. erectus, OH 9 from Tanzania.

Letter: Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya

F. Spoor, M. G. Leakey, P. N. Gathogo, F. H. Brown, S. C. Antón, I. McDougall, C. Kiarie, F. K. Manthi & L. N. Leakey

doi:10.1038/nature05986

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