Angustopila gracilis Pall-Gergely & Hunyadi, 2023

Pall-Gergely, Barna, Hunyadi, Andras, Vermeulen, Jaap J., Grego, Jozef, Sutcharit, Chirasak, Reischuetz, Alexander, Dumrongrojwattana, Pongrat, Botta-Dukat, Zoltan, Oerstan, Aydin, Fekete, Judit & Jochum, Adrienne, 2023, Five times over: 42 new Angustopila species highlight Southeast Asia's rich biodiversity (Gastropoda, Stylommatophora, Hypselostomatidae), ZooKeys 1147, pp. 1-177 : 1

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 ).

Figures

Figure 31. Distribution of Angustopila species.

Figure 65. Angustopila gracilis Pall-Gergely & Hunyadi, sp. nov. A paratype B-I holotype (HNHM 105296). Apertural (A, B), lateral (C), apical (D) and ventral (E) sides of the shell; aperture (F); sculpture on the protoconch (G), ventral (H) and frontal (I) surface of the body whorl.