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

Radula morphology of Cryptosemelus niger S. Tumpeesuwan & C. Tumpeesuwan, sp. nov. (paratype NHMSU-00055) A radula plate, teeth rows arranged in wide V-shape B close-up view of middle part of radula C close-up view of right side of radula D close-up view of right side of radula showing marginal teeth. Central teeth indicated by ‘C’; lateral teeth indicated by ‘L’; marginal teeth indicated by ‘M’.