Species identification and invasion pathways of an introduced snail Macrochlamys sp. in Japan

The various problems caused by invasive species have become more serious in recent years, and thus it is important to discuss their identifications and invasion processes. Phylogenetic and population genetic methods are effective tools for solving these problems. Some land snails, including the genus Macrochlamys, have invaded and established themselves worldwide as invasive species. In this study, we identified the species of Macrochlamys sp. from Japan and estimated their invasion pathways to Japan. Phylogenetic analysis showed that the Japanese snails were closely related to Macrochlamys indica from Bangladesh and West Bengal. Population genetic analysis also revealed that most of the Japanese snails were concentrated in single haplotype and were close in genetic distance. Detailed anatomical investigation of genitalia and oral organs showed morphological similarities between the Japanese and Bangladeshi snails, supporting the results of the phylogenetic analysis. These findings suggest that the Japanese Macrochlamys sp. is recognized as Macrochlamys indica and may have been introduced from the vicinity of Bangladesh and West Bengal and subsequently spread within Japan.