A molecular phylogenetic investigation of Cyathopoma (Prosobranchia: Cyclophoridae) in East Asia

The Cyclophoridae is the dominant group of operculated terrestrial snails in East Asia. The group consists of 4 subfamilies and about 300 species currently arranged in 34 genera. They occupy a range of habitats and exhibit considerable morphological diversity. Members of Cyathopoma are tiny white cyclophorid snails occurring in East Asia, Madagascar, and the Seychelles. The phylogenetic relationships of Cyathopoma are uncertain. In order to investigate the relationships among cyclophorids and within East Asian Cyathopoma species, we sequenced part of the mitochondrial cytochrome oxidase subunit I (COI) gene from 31 species of 9 genera of cyclophorids. We constructed phylogenetic trees using Neighbor-joining, Bayesian, and maximum-likelihood analyses. Phylogenetic relationships based on mitochondrial (mt)DNA sequences suggested that Cyclophorus, Cyclotus, Leptopoma, and Platyrhaphe are monophyletic. Combined with molecular and radular data, we concluded that Cyathopoma and Cyclotus are only distantly related. Cyathopoma iota has been considered to be a controversial member of this group. Through molecular and radular data, we found Cya. iota to be closer to Cya. taiwanicum than to Cya. micron, and concluded that Cya. micron, Cya. ogaitoi, Cya. iota, and Cya. taiwanicum belong to Cyathopoma. In addition we provide the first report of Cya. ogaitoi from Guizhou Province, China.