About a series of cylindrical shelled Granulina (Marginellidae) from north east Atlantic waters and the taxonomic organisation of the Granulininae

A series of tiny cylindrical shelled Granulina are reported as ranging off the North West African coasts, through the recent finding of several phenae. G. cylindrata sp. nov. is described from Senegal, the chromatism of its soft parts and the microsculpture of its shell are presented, as well as the variability of its shell morphology. The species is also recorded from the Cape Verde Islands, together with a closely related species quoted as Granulina sp. 1. A third cylindrical shelled species is recorded from Lanzarote, Canary Islands, as Granulina sp. 2. The relative demographic density of Granulininae is confirmed as being noticeably variable depending on the species. Granulina cylindrata sp. nov. and Granulina sp. 1 are placed in the same species group and compared to similar species ranging off North West Africa. Various groups are shown to occur in the Granulininae, distinguishable on the basis of shell outlines and macrosculptures. The placement of Granulina in Marginellidae is confirmed on the basis of several shell features. A discussion is held about the general issue of supraspecific organisation in the Granulininae, assessing the validity of taxonomic arguments in view of adequate groupings within the considerable morphologic disparity observed.