PHYLOGENY, SPECIES-LIMITS AND TAXONOMIC REVISION OF OTALINI (HELICIDAE) FROM NORTH-WEST AFRICA

The affinities and detailed phylogeny of the tribe Otalini of the Helicidae are elucidated from DNA sequence data, derived from all the recognised genera and most of the NW African species. The genus Theba (Thebini) emerges as the sister group of all Otalini. Eremina is placed here in a separate new tribe Ereminini; it forms a Glade sister to the combined Thebini and Otalini. The nine genera recognised within the Otalini are placed in two subtribes, as follows: Cantareusina (new subtribe, for Cantareus, Cornu, Erctella, Rossmaessleria), and Otalina (Maurohelix, Massylaea, Eobania, Otala and Loxana). Other nominal genera based on type species from NW. Africa are synonymised. The first comprehensive modern revisions of species limits in Loxana and Maurohelix are presented, based on studies of genital anatomy and shells from extensive recent collections, mapping of distributions and DNA sequence data. Numerous conchologically distinctive allopatric populations within the expanded concept of Loxana appear to be more realistically regarded as forming far fewer biological species. Hence, this supports reduction of five polytypic genera previously recognised (including Alabastrina and Atlasica) to the single genus Loxana. The habitat preferences of these species are described, their ranges are mapped and evolution and differentiation of their shell characters are discussed. Data supplementary to those from other recent studies are also presented for Rossmaessleria, Massylaea, Eobania and Otala. Massylaea and Eobania are maintained as separate genera based on new molecular and morphological data. One new species is described within Otala, three other species are recognised as valid and additions to that genus (O. juilleti, O. orientalis, O. pallaryi) and the placement of O. hieroglyphicula therein is confirmed. Evolution of the distal genitalia in Helicidae is discussed, revealing several remarkable instances of convergent evolution that had not been reported previously.