The microsnail genera Clostophis and Acinolaemus (Eupulmonata, Pupilloidea, Hypselostomatidae) from central Thailand, with description of three new species

Hypselostomatid microsnails of the genera <i>Clostophis</i> and <i>Acinolaemus</i> from limestone hills in central Thailand were studied and three new species are described. <i>Clostophis rhynchotes</i> Tongkerd & Panha, <b>sp. nov.</b> is diagnosed by a conical spire, long and descending tuba, 14 spiral striations on the last whorl, and only a single parietal lamella. In addition, a previously known species, <i>C. proboscideus</i>, is redescribed, and variations in its apertural dentition are also documented. In the genus <i>Acinolaemus</i>, two new sympatric species that clearly differ in shell shape are described. <i>Acinolaemus rhamphodontis</i> Tongkerd & Panha, <b>sp. nov.</b> is characterised by a depressed conical spire with a long and descending tuba, and eight apertural dentitions, while <i>A. corusticorus</i> Tongkerd & Panha, <b>sp. nov.</b> possesses a conical shell without a tuba and nine apertural dentitions. Specimens from the type locality of <i>A. ptychochilus</i> (the type species), <i>A. cryptidentatus</i> and <i>A. mueangonensis</i> are re-described and compared with the new species. The living snails of <i>A. mueangonensis</i> and <i>A. rhamphodontis</i> Tongkerd & Panha, <b>sp. nov.</b> possess blackish to translucent bodies. In addition, COI barcoding data for <i>Clostophis</i> and <i>Acinolaemus</i> are provided for the first time.