Nomenclature of Genus-Group Names of Recent Asian Paludomidae (Gastropoda: Cerithioidea), with a Revision of Paludomus (Odontochasma) Stomatodon (Benson, 1862) from the Western Ghats, India

ABSTRACT The Oriental region is among the world's biologically most diverse regions, but also among the most biotically threatened, especially with regard to freshwater biota. The Cerithioidea comprise several families and are a major component of the freshwater gastropod fauna in the Oriental region. Among these, the Paludomidae include numerous taxa mostly described in the 19thcentury that are in many cases badly in need of revision. As an initial step towards a better understanding of the evolutionary systematics of the family, we here review the genus-group taxonomy and nomenclature of Asian Paludomidae. We show that Paludomus Swainson, 1840, Philopotamis Layard, 1855, Ganga Layard, 1855, and Odontochasma Tomlin, 1930, are available names for morphology-based genus-group taxa of Asian Paludomidae. By selection of Melania modicella I. Lea & H. C. Lea, 1851, as type species of Rivulina I. Lea & H. C. Lea, 1851, and by the designation of a neotype for Paludomus (Hemimitra) retusa Swainson, 1840, Rivulina and Hemimitra Swainson, 1840, can both be regarded as synonyms of Paludomus s. str. By selection of Paludomus sulcatus Reeve, 1847, as its type species, Heteropoma Benson, 1856, becomes an objective junior synonym of Philopotamis Layard, 1855. Furthermore, we show that the type species of Tanalia Gray, 1847, which has often been used for a subdivision of Paludomus or as a distinct genus, belongs to the Neritidae and that Odontochasma Tomlin, 1930, has been validly proposed as a replacement name for the preoccupied name Stomatodon Benson, 1862. Finally, we revise Paludomus (Odontochasma) stomatodon Benson, 1862, on the basis of available type material, describe its radula for the first time, and compare it with published data on radulae of other Asian paludomids. Taxonomic redundancy in the genus-group in Asian Paludomidae is estimated to be 50% and may be as high as 88% depending on taxonomic opinion.