First record and description of a new species of the land snail genus Pearsonia Kobelt, 1902 (Cyclophoridae: Pterocyclinae) from Thailand, with a note on radula morphology

A new cyclophorid species of the genus Pearsonia possessing a sub-discoidal shell with a sutural tube was discovered from a dolomitic limestone hill in Lamphun Province, northern Thailand. This discovery also represents the first record of the genus in Thailand. Pearsonia lamphunensis, new species, differs from the related congeners by the zig-zag brown stripes that are present on both dorsal and ventral sides of the shell. The radula morphology of the genus Pearsonia is examined for the first time. The central cusps of both central and lateral teeth are shovel-shaped, and the central cusp's width is more than half that of the tooth's width. Comparisons of the radula morphology of Pearsonia lamphunensis, new species, and the recently described Pterocyclos diluvium Sutcharit & Panha in Sutcharit et al., 2014, suggests that Pearsonia is more closely related to Pterocyclos than Rhiostoma, which has fewer cusps in the outer lateral teeth, and thus differs from both aforementioned genera.