THREE NEW SPECIES AND A NEW GENUS OF HYPSELOSTOMATIDAE (GASTROPODA: PULMONATA) FROM CONG TROI CAVE, NORTHERN VIETNAM

The Hypselostomatidae Zilch, 1959 comprise a family of minute pupilloid snails usually endemic to limestone habitats in single hills, adjacent hill ranges, and in caves of Southeast Asia. Except for one molecular study, their taxonomy is largely conchologically driven. In this work, shell material derived from sediment samples from the Cong Troi Cave in Northern Vietnam is examined and taxonomically assessed. Altogether, five species are recognized. Three new species are described: Angustopila stochi Páll-Gergely et Jochum, sp. n., Tonkinospira tomasini Páll-Gergely et Jochum sp. n. and Dentisphaera maxema Páll-Gergely et Jochum, sp. n. For the latter species, Dentisphaera Páll-Gergely et Jochum a new genus is erected. Another hypselostomatid species is found to be identical with the original sample of Angustopila subelevata Páll-Gergely et Hunyadi, 2015 from Guangxi, China. This is the first record of A. subelevata from Vietnam. The fifth species closely resembles Pupisoma sp. from Thailand. Though figured here, it is not assessed taxonomically in this work