A new species of Scissurella from the Azores with discussions on Sinezona semicostata Burnay & Rolan, 1990 and Sinezona cingulata (O.G. Costa, 1861) (Gastropoda: Vetigastropoda: Scissurellidae)

Abstract

A new species of Scissurella d’Orbigny, 1824 from the Azores is described and compared to similar species from the eastern Atlantic and Mediterranean areas: Sinezona cingulata (O.G. Costa, 1861), Scissurella costata d’Orbigny, 1824, Sin. semicostata Burnay & Rolán, 1990, Sci. lobini (Burnay & Rolán, 1990) as well as two representatives from the Caribbean, Sin. confusa Rolán & Luque, 1994 and Sci. redferni (Rolán, 1996). The description and comparisons are based on shell and radula morphology examined by scanning electron microscopy. The species that are considered here are described by features including: shell shape, shell sculpture, shape of teleoconch I, which begins after the protoconch and ends at the onset of the selenizone and teleoconch II which extends from the selenizone to the aperture, presence or absence of a slit or foramen, details of the umbilical region and protoconch sculpture and width. Scissurella azorensis n. sp. is characterized by the protoconch sculpture, which contains axial cords on the outer margins only, having a open umbilicus region, teleoconch I being greater then one whorl and the amount of strong axial cords over the entire shell. The distributional range for Sin. semicostata is extended to the Salvage Islands. Sinezona fayalensis (Dautzenberg, 1889), Sin. depressa (Watson, 1897) and Sin. crossei (Folin, 1869) are compared to Sin. cingulata to show synonymy.