structural:expansion
Transition from Acheulean

ESA Acheulean sites are well documented across West Africa (except from the most tropical regions) but mostly remain undated.A few late Acheulean sites ("MSA" in the sense of late Acheulean, not Levallois) have been dated. Middle Pleistocene (pre 126 kya) sites are known from the northern Sahelian zones, while Late Pleistocene (post 126 kya) sites are known both from northern and southern West Africa. Unlike elsewhere in Africa, MSA sites appear to persist until very late, down to the Holocene boundary (12 kya), pointing to the possibility of late survival of archaic humans, and late hybridization with H. sapiens in West Africa. Furthermore, such results highlight significant spatiotemporal cultural variability and suggest that long inter-group cultural differences played a major role in later stages of human evolution in Africa.