Homo Erectus Revisited: Aspects of Affinity and Diversity in a Pleistocene Hominin Species

Fossil material assigned to Homo erectus is reviewed and the composition, integrity and morphological range of the species explored, to investigate its phyletic status and possible components of geographical and temporal variation. There is no convincing morphological case for differentiating early African specimens (H. ergaster) or "Meganthropus"material from H. erectus and claims for their specific identity seem to reflect evolutionary models and perceptions of the process rather than the characteristics of the fossil specimens themselves. Ileret and Dmanisi fossils indicate marked cranial variation in early H. erectus, with SK 847 a similar or closely related form. New dates and clarified stratigraphy indicate early hominin presence in Java and a correspondingly long interval between early and latest H. erectus there. Regional trends include some increase in brain size and cranial robusticity (Africa), dental reduction (Java and China), increased brain size and cranial gracilisation (Java). Contrasts are, however, limited and could well reflect drift rather than selection, especially in SE Asia. Variation in cranial (? and body) size apparently persisted in African erectus with possible behavioural and socio-ecological correlates. Similar variability is lacking among the Asian fossils, implying major differences between African and Asian populations, but much more fossil evidence is needed to resolve this. Late Lower Pleistocene African H. erectus populations were ancestral to more derived forms, with the species persisting in Asia until Middle-Upper Pleistocene times. H. floresiensis was probably derived from SE Asian H. erectus via a transilience event and selection for endemic dwarfing.