The family Nassariidae (Gastropoda: Buccinoidea) from the late Neogene of northwestern France

In this paper we revise the nassariid Plio-Pleistocene assemblages of northwestern France. Twenty-eight species are recorded, of which eleven are described as new; Nassarius brebioni nov. sp., Nassarius landreauensis nov. sp., Nassarius merlei nov. sp., Nassarius pacaudi nov. sp., Nassarius palumbis nov. sp., Nassarius columbinus nov. sp., Nassarius turpis nov. sp., Nassarius poteriensis nov. sp., Nassarius plainei nov. sp., Nassarius martae nov. sp., Nassarius gendryi nov. sp., five are left in open nomenclature. Two nassariid genera are recognised (Nassarius and Demoulia). The ‘Redonian’ assemblages and localities are grouped in four assemblages (Assemblages I – IV) corresponding to the four major stratigraphic groups of deposits recognised in the post mid-Miocene sequences of northwestern France. Assemblages I and II are not revised in this paper. Assemblage III contains a highly endemic nassariid species, known only from the northwestern French ‘Redonian’ deposits and is cool in character. Assemblage IV has the most diversified nassariid fauna, both in species, species groups, and contains the relatively thermophilic nassariid genus Demoulia. It is the most cosmopolitan in character, with the greatest affinity to the North Sea Basin fauna, but also shares common elements with the coeval Mediterranean assemblages. The high diversity and thermophilic character of this assemblage is unexpected, and cannot be explained at this time.