New species of the dancing semislug Cryptosemelus Collinge, 1902 (Eupulmonata, Ariophantidae) from Loei Province, northeastern Thailand with a key to genera of mainland Southeast Asian semislugs and a key to species of the genus

Abstract

In this study, we describe a new dancing semislug from a limestone hill area in northeastern Thailand. Cryptosemelus niger sp. nov. differs from the three recognized congener species from western and southern Thailand, due to differences in their body and shell lobes coloration, appearance of penial caecum, shape and surface texture of penis and epiphallus, and radula formula and morphology.