LAUSR

Abstract The arrival and disappearance of the Acheulean technocomplex in Europe, and specifically in the Iberian Peninsula, is a longstanding topic of discussion with relevance for unravelling the Middle Pleistocene human occupation dynamics of the continent. Despite containing one of the first Acheulean sites excavated in Europe (As Gandaras de Budino site), the Mino River basin (north-western Iberian Peninsula) remains understudied and has yielded relatively limited information on the temporal and spatial dynamics of the regional Acheulean technocomplex over the last fifty years. Here we present a systematic archaeological and numerical dating study of a previously undocumented Acheulean site located in the lower Mino River basin (Arbo site, Pontevedra, Spain). This newly discovered site preserves a late Middle Pleistocene Acheulean assemblage that has been dated to pre-Marine Isotope Stage 5 by a combination of post-infrared infrared stimulated luminescence (pIR-IR) and electron spin resonance (ESR) dating of sedimentary silicates. The new excavations reveal that the site preserves a dense concentration of artefacts made from allochthonous raw materials. Detailed lithic analyses show that the industry has some elementary flake production systems devoid of Levallois cores, but with supplementary non-standardised flake tool types and some large cutting tools (LCTs) - mainly handaxes that are usually finalized with soft-hammer. The results obtained at Arbo complement those obtained recently at the nearby Porto Maior site, as well as the seminal study of As Gandaras de Budino, and demonstrate an important Acheulean and hominin presence in the Mino River basin during the second half of the Middle Pleistocene.