Hypselostoma utongense Panha & J. B. Burch, 2004

Hypselostoma utongensis Panha & Burch in Panha et al. 2004: 72–73, fig. 10.

Hypselostoma utongensis — Panha and Burch 2008: 103, fig. 87; Dumrongrojwattana and Wongkamhaeng 2024: 324, fig. 8.

Material examined.

Thailand • 16 shells; Kanchanaburi Province, Erawan National Park, Erawan Falls Trail; 14°22.310'N, 99°08.699'E; 17 Feb. 2015; A. Hunyadi leg.; coll. HA .

Type locality.

“ Tam Sua Hill, Utong District, Supanburi Province, 14°34'27"N, 99°46'26"E, 80 meters elevation ”.

Differential diagnosis.

This species is similar to two Hypselostoma which share the completely (or almost completely) flat shell with strongly upturning last whorl ( H. khaowongkot and H. tridentatum). From them, it most obviously differs by its hooked upper and lower palatal plicae which are blunt in the former.

Distribution.

This species is known from two provinces in Thailand, Supanburi (type locality) and Kanchanaburi (this study).

Remarks.

In some specimens, previous whorls are partly sunken into the last while in others completely.

2. Hypselostoma hungerfordianum group

Diagnosis. Hypselostoma hungerfordianum group is characterised by a peculiar shell surface sculpture, as if “ scaly, granulated ”. This surface sculpture is unique and we assume that all the species which share this trait are possibly more closely related.

Remarks. This group has representatives across Southeast Asia and includes 19 species. The distribution spans from Kayin State in Myanmar and eastwards to western Cambodia (Battambang Province). Southernmost localities are known in Peninsular Malaysia while northernmost come from Loei Province in Thailand.