The Gelasian gastropod fauna of Selsoif (Manche, France)

We have little understanding of the evolution of modern marine faunas from the European Atlantic coasts. In NW France very rich Neogene and early Quaternary mollusc assemblages occur that may shed light on the evolution of these modern faunas. Here we describe a Gelasian gastropod assemblage consisting of 76 species-level taxa from Selsoif (Manche, France), recovered from a sand extraction site between 1989-2020 by various collectors. The fauna reflects a range of intertidal to shallow subtidal palaeoenvironments. A few reworked Eocene fossils were also recovered. The extant portion of the Selsoif fauna is dominated by species with a Lusitanian signature, but also contains common species that nowadays have a Boreal-Celtic and Mediterranean signature. Furthermore, the fauna has quite some species in common with Early Pleistocene North Sea Basin faunas and also contains a few endemic species such as Calliostoma normanensis n. sp., Seila quinquecarinata n. sp., Alvania selsoifensis n. sp., Admete trigostomoides n. sp. The Selsoif fauna therefore represents a transitional fauna between Neogene and modern marine faunas of the European Atlantic.