The Land Snail Genus Opisthoporus Benson In L. Pfeiffer, 1851 (Gastropoda: Caenogastropoda: Cyclophoridae) From Vietnam, With Description Of A New Species

Species of the genus Opisthoporus Benson in L. Pfeiffer, 1851 (family Cyclophoridae) occurring in Vietnam are reviewed and presented. In total, three species arc included: Opisthoporus beddomei Dautzenberg & Fischer, 1908; O. lubricus Dautzenberg & Fischer, 1908; and O. thuathienhuensis, new species. Opisthoporus thuathienhuensis, new species, differs most distinctly from related congeners by its small inverted U-shaped breathing tube that has its distal end touching the last whorl. The new species is known only from limestone hills of Thua 'linen Hue Province, central Vietnam, where terrestrial gastropod fauna is diverse, but relatively poorly known. This discovery represents the first record of the genus Opisthoporus in central Vietnam. A checklist of Opisthoporus taxa (mainly literature data) is presented.