| Resumo: | [EN] The littoral species of the genus Crisilla Monterosato, 1917 from the Azores, Madeira, Selvagens and the Canary Islands are reviewed. Some species from the West African coasts have been also studied and the type species of this genus, the European Crisilla semistriata (Montagu, 1808), has been taken as reference. In total we have studied 19 species, of which 4 are described as new, 3 from the Canary Islands and 1 from Ghana in the Gulf of Guinea. Two of the species, Crisilla quisquiliarum (Watson, 1886) and Crisilla ugesae (Verduin, 1988), previously included in the genus Setia H. Adams & A. Adams, 1852 are here transferred to Crisilla. For each species a detailed description is given supported with SEM photographs, and data about its known distribution and bathymetric range are provided. The study concludes that, like Alvania Risso, 1826, the genus Crisilla seems to be polyphyletic and appear to represent some independent lines of transition between the species with thicker shell and well-marked sculpture (genus Alvania) to those with thinner shell and more or less smooth surface (genus Setia). Finally a key to adult shell of all the species that we consider belonging to the genus Crisilla is provided.
|
|---|
