Phylogenetic position of Canaridiscus and reestablishment of Gonyodiscus (Gastropoda: Discidae)

The genus Canaridiscus M. R. Alonso & Ibáñez, 2011, endemic to the Canary Islands, has a curious taxonomic history and is currently defined based only on the peculiar anatomy of its genital organs. Its relationship to European Discus species and other members of the family Discidae is unclear and its status as a distinct genus remains tentative. In the present study we include a species of Canaridiscus, C. textilis (Shuttleworth, 1852), in a molecular phylogenetic framework of the Discoidea to investigate its position in the superfamily’s tree. Canaridiscus is retained as a distinct genus in Discidae, but Discus is shown to be polyphyletic. Thus, the genus Gonyodiscus Fitzinger, 1833 is here resurrected to include 2 European species, reclassified as G. perspectivus (Megerle von Mühlfeld, 1816) and G. rotundatus (O. F. Müller, 1774). Discus Fitzinger, 1833 is restricted to a clade containing mostly North American species.