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

Cryptosemelus niger S. Tumpeesuwan & C. Tumpeesuwan, sp. nov. Living snail in natural habitats. Photograph by Chanidaporn Tumpeesuwan 12 December 2018 A C. niger crawling on soil in limestone crevice (white circle) B close-up view in living position C, D semislug was moved to green leaf for taking photo C left side represents left shell lobe (lsl) D right side represents right shell lobe (rsl), left shell lobes (lsl), and left dorsal lobe (ldl).