Bone retouchers and end-scrapers side by side at Bushman Rock Shelter: Exploring a ca. 100,000-year-old technological imbrication in southern Africa

A growing body of archaeological data points towards distinct cultural innovations during Marine Isotopic Stage (MIS) 5 in Africa. At Bushman Rock Shelter in South Africa, we described previously a large corpus of end-scrapers that constitute a technological novelty in the context of MIS 5 developments. Here, we describe 25 bones with impressions collected from the same deposits. Middle Stone Age layers at the site represent a succession of distinct technological phases, but the bones with impressions are strictly associated with one of them only, characterised by the presence of end-scrapers. Our refined optically stimulated luminescence and U-series chronology, presented here, dates securely this technological association to 103 ± 3 ka. Amongst the bones with impressions, there is a marked preference for the diaphyses of large ungulate long bones. Scraping marks linked to periosteum removal and evidence of fresh breakage indicate the use of bones while still fresh. Macro- and microscopic characteristics of the used areas confirm that the bones were used during percussive activities. The orientation of the bone surface modifications indicates repeated, similar technological gestures. We propose that these bones with impressions are bone retouchers that were fully integrated into the production of the end-scrapers and that they document a clear technological imbrication between the processing of animal resources and the manufacture and use of stone tools. We argue that the use of bones in lithic retouching or resharpening activities represents a critical step in the technological process that led to the exploitation of bone as a versatile raw material by hunter-gatherers.