Angustopila gracilis Pall-Gergely & Hunyadi sp. nov.

Fig. 65

Type material.

Holotype: Laos • 1 empty shell (H: 0.94 mm, D: 0.85 mm); Bolikhamsai Province, 15 km southeast from centre of Lak Sao, 4.5 km northeast on a side road, Phu Phako, limestone gorge (locality code: 2019/110); 18°06.55'N, 105°03.78'E; 510 m a.s.l.; 2 Oct. 2019; A. Hunyadi leg.; HNHM 105296.

Paratypes: Laos • 699 adult + 207 juvenile shells; same data as for the holotype; coll. HA (juvenile shells are also of characteristic shape for the species, and thus, they are also selected to be paratypes) • 10 shells, same data as for the holotype; coll. JJV.

Diagnosis.

A medium-sized, concave-conical Angustopila species with conspicuously narrow initial whorls and wide body whorl, aperture wide with a regularly developed parietal tooth, and a very weak, blister-like lower palatal tooth.

Description.

Shell of normal size for the genus, higher than wide or rarely slightly wider than high; off-white, concave-conical with conspicuously narrow initial whorls and wide body whorl; last whorl widest from standard apertural view; protoconch consists of 1.25 whorls, spirally striated with the exception of the first protoconch whorl; teleoconch with weak, irregular radial ribs and equidistantly, sparsely-spaced, spiral striae (ca. 12-16 on body whorl from standard apertural view); whorls 4.25-4.5, rounded; aperture oblique to shell axis in lateral view; umbilicus wide, slightly excentric; aperture nearly rounded, wide; sinulus wide, weakly separated; peristome expanded, not reflected; parietal callus not detached from penultimate whorl; parietal tooth elevated, straight, starts in some distance from peristome, rather long; lower palatal tooth tiny, blister-like.

Measurements (in mm).

H = 0.89-0.97, D = 0.82-0.95, H/D*100 = 93.7-113.4 (n = 7), RUD = 26.5-31.8 (n = 4).

Differential diagnosis.

Angustopila antidomedon sp. nov. and A. pustulata sp. nov. possess a less rounded (rather depressed-rounded) body whorl and a less rounded aperture. Moreover, none of those species have such slender initial whorls.

Etymology.

This species is named after the slender (Latin: Angustopila gracilis) initial whorls.

Distribution.

Angustopila gracilis sp. nov. is known from the type locality only in Bolikhamsai Province of Laos (Fig. 31).