Streptaxid microcosm: the radiation of the endemic genus Pseudelma Kobelt 1904 (Gastropoda Pulmonata Streptaxidae) on Mayotte, Comores

Streptaxidae is a family of carnivorous tropical land snails, with extensive radiations in the Neotropics, Africa and Asia. About 40 species have been described from the Comores. The genus Pseudelma Kobelt 1904, endemic to Mayotte, is revised. Its anatomy, reported here for the first time, places it in the subfamily Enneinae, and indicates a close relationship to Maurennea Schileyko 2000 from the Comores and Mauritius. Five previously known species, and two new species, are recognized and classified in three genus-group names, Pseudelma, Fultonelma Haas 1951, and Marielma n. subgen. Species of Pseudelma have a high level of syn-topy, and up to six species may co-occur at one locality. Besides Mayotte, Pseudelma had been recorded only from Madagascar, but we suggest that Pseudelma madagascariensis Fischer-Piette, Blanc & Vukadinovic 1974, described based on two shells without precise locality data, is a synonym of Elma messageri (Bavay & Dautzenberg 1904), a species from Vietnam. We thus reject its Madagascan type locality and restrict the distribution of Pseudelma to Mayotte, Comores.