Streptaxidae (Mollusca: Gastropoda: Pulmonata) of the Seychelles Islands, Western Indian Ocean

The taxonomy of the species of the terrestrial carnivorous snail family Streptaxidae of the Seychelles archipelago is reviewed with the exception of the three species of the genus Priodiscus (vide Gerlach, 1995). All 18 species are restricted to the northern, granitic islands. This paper describes 15 species, including two new genera (Silhouettia and Careoradula), and four new subspecies (Edentulina dussumieri reservae, E. d. silhouettae, E. d. praslina, Stereostele nevilli parvidentata). The nominal taxon Streptaxis (Imperturbatia) constans var. silhouettae is raised to species level to become the type species of the new genus Silhouettia. The type species of Careoradula is Streptaxis (Imperturbatia) perelegans. Anatomical descriptions and figures are provided for 13 species; the new genus Careoradula is distinct from all other streptaxids by the complete absence of a radula and associated structures. Distribution is featured on individual maps for each species. The paper concludes with a key to the shells of all species, those of Priodiscus included, and some preliminary considerations on the distribution of this group in the Seychelles archipelago.