What can microshells tell us? A case-study from the Palaeolithic site of Riparo Bombrini (Balzi Rossi, NW Italy)

The exploitation of marine molluscs during the Middle and Upper Palaeolithic is a topic that has been extensively investigated over the last few years, shedding light on human adaptation in coastal environments. However, such studies mainly focus on the role of marine molluscs in the subsistence practices of the hunter-fisher-gatherers of the Mediterranean Basin. Although small, non-dietary gastropods found in archaeological deposits have the potential to provide important clues regarding past human activities, their role is still little investigated. This research explores the question of whether taphonomy could be useful for the interpretation of these less conspicuous “incidental” shell remains found in archaeomalacological assemblages. In this paper we present the results of a taphonomic study carried out on a total of 314 Bittium shells recovered in the Mousterian and Protoaurignacian levels of Riparo Bombrini, a collapsed rockshelter in the Balzi Rossi Palaeolithic site complex (NW Italy). How did these small, non-dietary gastropods come to be deposited? Are they an unintentional by-product of certain harvesting techniques, or the result of a deliberate gathering? Or, could natural factors be responsible for their presence at the site? To answer these questions, different types of taphonomic processes were considered. Comparing the Bombrini archaeomalacological remains and modern shells accumulated on beaches leads us to propose that the most likely cause of their presence at the site is a correlation between Bittium shells and small sea pebbles, rather than the accidental transport of these shells with algae and seagrasses that could have been brought back to the site.