Bensonella wangviangensis

2.Bensonella wangviangensisgroup Diagnosis. This species group is characterised by angular lamella as strong as the parietal or even stronger, fully reaching the peristome edge, palatal tubercle not in its typical form but clearly represents a slightly discontinued part of the upper palatal plica (thus, it is of more lamella-like than tubercle-like appearance) and closely situated angular lamella and palatal tubercle which clearly separated the sinulus from the rest of the aperture. Remarks. Four species are assigned to this group and they inhabit northern Thailand (Loei Province) as well as adjacent territories in Laos (Vientiane and Khammouane provinces). Due to the same distribution and very similar overall shell morphology, these species are probably closely related.