Aurignacian grinding stone from Surein I (Crimea): “trace-ing” the roots of starch-based diet

This study is applied to the unique grinding stone from Surein I retrieved in the Aurignacian layers of the rockshelter located in the south of the Crimea Peninsula. Our research enables us (i) to make reliable inference on the agency establishing the functional modification on the surface of the Surein I grinding stone, (ii) to demonstrate this grinding stone served as steady surface (Face A) to mechanically process plant materials including roots and tubers (under surface storage organs, USOs) and (iii) to set a chrono-cultural framework for starchy plants tenderization, also responding to key issues relating to the dietary breadth of early waves of Homo sapiens at the northern latitudes. We present a pilot research design which integrates data derived from macro and micro-scales techniques, by coupling use-wear traces analysis and use-related starch granules observation. The multi-scale approach allows distinctive resolutions for surface texture analysis thanks to the combined use of stereo, metallographic and digital microscopes; whereas transmitted and polarized light microscopes were used to observe use-related biogenic residues (U-RBR), namely starch granules, and SEM provided resolution down to the nano-scale. Our data suggest that Homo sapiens was exploiting the rich environment of the Pontic steppe-grassland since its earliest presence in south-eastern Europe by processing starchy plants to obtain calorific food. Moreover, this study brings fresh lines of evidence to the broadening of dietary strategies during late MIS 3 (40–25 ka calBP) by analysing ground stones from the poorly investigated non-flaked industry, and opens new scenarios for the reasoning on Homo sapiens successful colonization of Eurasia.