Hypselostoma edentatum

Hypselostoma edentatum (Panha & J. B. Burch, 2002) Figs 111 R, 134, 154 Systenostoma edentatum Panha & Burch, 2002 d: 121–124, fig. 4. Systenostoma edentata — Panha and Burch 2008: 119–120, fig. 102. Hypselostoma edentata — Jochum et al. 2014: 31; Dumrongrojwattana and Wongkamhaeng 2024: 324, fig. 8. Type material examined. Thailand • holotype; 1997; S. Panha leg.; CUMZ ver. 022. Additional material examined. Thailand • 12 shells; Chiang Rai Province, limestone knoll, 4 km NE of Ban Pa Ngae limestone knoll, base of limestone ledge; 19°34.3167'N, 99°59.2333'E; 410 m a. s. l.; F. G. Thompson leg.; 12. May 1988; locality code FGT-4429; UF 380304. Type locality. “ Tamphatai National Park …, Phrae Province, 18 ° 36 ” 20 ' N, 99 ° 53 ” 49 ' E, 650 meters elevation …, Thailand … ”. Differential diagnosis. This species differs from all of its congeners by the absence of apertural barriers, which makes it superficially more similar to some Tonkinospira species. From all similar toothless Aulacospira species from Thailand, this species differs by the presence of raised spiral striation. See also under H. panhai. Distribution. This species in known from Lampang and Chiang Rai provinces in Thailand. Remarks. The type locality of this species is not in Phrae but in Lampang province. Specimens from Chiang Rai province shared the same shell morphology but were slightly more depressed than the holotype.