Hypselostoma W. H. Benson, 1856

Genus Hypselostoma W. H. Benson, 1856 View in CoL

Diagnosis.

Shell tiny, turbinate, high-spired, or discoidal. Peristome adnate or separated from the adjacent body whorl forming a tuba; edge of peristome expanded. Aperture with four or more parietal and angular apertural lamellae or plicae (barriers), except in Hypselostoma edentatum (Panha & J. B. Burch, 2002 d) and H. pongrati sp. nov. which have no apertural barriers and H. sichomphuense sp. nov. which has only three barriers ( Panha and Burch 2008; Gojšina et al. 2025). The genitalia of Hypselostoma possess a penis that is more swollen than the epiphallus; gametolytic sac connects to vagina very close to atrium, divided into two parts, with the proximal part swollen and larger than the penis (except in H. cultura ( Tanmuangpak & Dumrongrojwattana, 2022) , in which the gametolytic sac has a long duct between proximal and distal part, while there is no swollen proximal part in H. depressispira ( Berry, 1963)) . These anatomical characters differ from the genus Aulacospira Möllendorff, 1890 , whose gametolytic sac connects to the vagina far from the atrium ( Dumrongrojwattana and Tanmuangpak 2020)