Revision of deep-water species in Granulina (Gastropoda: Granulinidae) from Mauritania and Western Sahara

Empty shells (thanatocoenoses) have been reviewed of species in the genus Granulina (Gastropoda: Granulinidae) from the lower shelf and upper bathyal zones off Mauritania and Western Sahara. We encountered nine species of which four were already known from off Mauritania. Four new species are proposed herein: Granulina reginae sp. nov., G. ronaldi sp. nov., G. sandrae sp. nov. and G. sigridae sp. nov. These four sympatric new species lack labial denticles and they probably form a phyletic clade with a common ancestor. Most hitherto known species in Granulina from the NE Atlantic Ocean and the Mediterranean possess labial denticles. One additional new species with denticles was left in open nomenclature because the material available was considered inadequate. Species in Granulina from Mauritania and Western Sahara have not been found off NW Morocco or the Canary Islands, and the species known from NW Morocco and the Canary Islands have not been found off Mauritania and Western Sahara. The southern extents of the distributions of the Mauritanian species are currently uncertain as additional sampling would be required off Senegal or further South. A key to Mauritanian species in Granulina is given.