Taxonomic revision of terrestrial snails genera Macrochlamys, Cryptozona and Hemiplecta in Thailand

Abstract

Terrestrial snail genus Macrochlamys in the present study contains the genital characteristics as of the genus Sarika which later carefully studied from the literatures and collected specimens, can be concluded that the previous reported Macrochlamys from Thailand must be classified into Sarika by the straight penial appendix and penial retractor muscle position. Macrochlamys asamurai and Syama diadema also cotain the spineless shaped spermatophore as of the genus Sarika. The main genital characteristic of genus Cryptozona is blackish epiphallus and long epiphallic caecum. While the genus Hemiplecta has a very short spermatheca and blunt knob epiphallic caecum. Hemiplecta siamensis from Saraburi Province has genital description as of the genus Sarika and must be reclassified into Sarika siamensis. Hemiplecta weinkauffina in this study looks very close to the genus Dyakia in a short dart sac with having a duct of dart gland at the distal end, spermatheca on the base of dart sac, no penial appendix and no epiphallic caecum. It must be reclassified into genus Dyakia. The mean ratio of spermatheca length to vas deferens length (SL/VDL) could be used to classified in generic level, and also could be classified in specific level of Cryptozona siamensis 1 and Cryptozona siamensis 2. Other ratios such as penis length to vas deferens length (PeL/VDL), penial appendix length to vas deferens length (PAL/VDL) and vas deferens length to epiphallus length (VDL/EL) could be used to classified in specific level of Hemiplecta distincta and Hemiplecta neptunus