Anatomical and phylogenetic investigation of the genera Alabastrina Kobelt, 1904, Siretia Pallary, 1926, and Otala Schumacher, 1817 (Stylommatophora, Helicidae)

Abstract. This study presents new insights in the anatomy of genital organs of some large helicid gastropods from northern Africa. The genetic analysis with the markers COI, 16S, H3, and 5.8 S rRNA+ITS2 reveales a high support for Alabastrina and Otala as separate evolutionary lineages within the Otalini. The position of Siretia as another separate lineage within the Otalini is discussed. “Tingitanaminetteidecussata” clusters within the O.xanthodon clade and confirms that the genus Tingitana can be synonymised with Otala. The genus Alabastrina differs from all other known genera by possession of a penial appendix. This character state is also found in topotypic A.tistutensis. Examination of the twin penial papilla system in Otala recovers a reduction of the proximal penial papilla in O.punctata. The position of Helixmurcica as a separate subspecies of O.lactea is not supported, and it is here considered to be a synonym of the latter species.