Two new species of genus Anceyoconcha S. Tumpeesuwan & C. Tumpeesuwan, in Nahok et al., 2020 (Gastropoda: Pulmonata: Camaenidae), from northeastern Thailand

Abstract

Two new species of the Indochinese tree snail Anceyoconcha S. Tumpeesuwan & C. Tumpeesuwan, in Nahok et al., 2020, are described from natural forests and forestry plantations on sandstone and basalt hills in northeastern Thailand. These snails can be found on trees from the foothills to higher elevations, around 1–2 m above ground level. The new species Anceyoconcha carinata and Anceyoconcha elongata possess the key characters of the genus, namely, a shell that is sinistral, ovate conic to elongate conic with six to nine slightly convex whorls, semi-transparent, and lustrous. The dart sac and mucous glands are absent, and the flagellum long cylindrical and tapering. Both new species differ from all previously described species by unique characters of shell; length of penis, vagina and free oviduct; and flagellum shape. The phylogeny based on the mitochondrial and nuclear DNA and genetic distances suggest that all Anceyoconcha species form a well-supported monophyly, and that both new species are differentiated from the rest of the congeners. © National University of Singapore.