A revision of Obscurella Clessin, 1889 (Gastropoda Prosobranchia: Cyclophoridae)

A review is presented of the eight recent species of Obscurella, one of which, O. asturicum spec. nov. is new to science. The subdivision in species is supported by sympatric occurrence without intermediate forms. A key is given and the shell, soft parts, ecology and distribution of the species are described. Sexual dimorphism is evident in the shells of all species. Micropenises have been found occasionally in males of five species; in O. oscitans (Gofas, 1989) all male specimens have a micropenis. Based on differences in shell and preferred habitat, three subgenera are distinguished within Obscurella, viz. Obscurella, Cantabrica subgen. nov. and Canestrinia subgen. nov.