Homo erectus technological behaviors during the Middle Pleistocene Transition: Engaji Nanyori, Oldupai Gorge

The Acheulean technocomplex is a milestone in the evolutionary adaptability, technological development, and dispersal of Homo erectus. While the earlier phases of the Acheulean have been thoroughly investigated in Eastern Africa, reliably dated assemblages in environmental context spanning the Middle Pleistocene Transition (1.2–0.8 Ma) are extremely rare at a global scale. Engaji Nanyori (Bed III, Oldupai Gorge) is one of a few sites offering a window into Acheulean behavior during this critical period of climatic crisis and aridification. We study lithic assemblages from recent excavations of an Acheulean occupational sequence dated 1.1–0.9 Ma, revealing a stable technological system that focused on flake production by relying on Oldowan-like knapping strategies while rendering infrequent the manufacture of Large Cutting Tools. We present a continental analysis of Acheulean technologies during the Middle Pleistocene transition aimed at exploring the influence of climatic, ecological, and environmental instability on adaptability. Our results underscore the numerous similarities between the technological strategies of Engaji Nanyori and those of the penecontemporary sites, illustrating the uniform character of African Acheulean assemblages regardless of their temporal, geographical or environmental settings.