Angustopila steffeki Pall-Gergely & Grego, 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 steffeki Pall-Gergely & Grego sp. nov.

Fig. 81

Type material.

Holotype: Laos • 1 empty shell (H: 0.64 mm, D: 0.74 mm); Bolikhamsay Province, large spring lake at S foot of limestone massif 2 km NNE of Na Pavan village, ca. 5 km from Phontan crossing at road 8 (locality code: JG16); 18°13.30'N, 104°44.81'E; 18 Feb. 2017; J. Grego leg.; NHMUK 20170296.

Diagnosis.

A small, depressed-globular Angustopila species with the aperture oblique to shell axis, a strongly protruding aperture, and relatively weak parietal and rather strong upper palatal tooth.

Description.

Shell small, wider than high; off-white, depressed-globular with domed spire; body whorl widest in standard apertural view; protoconch consists of 1.25 whorls, microstructure finely pitted and granular with a powdery superficial texture and with weak spiral striae (although holotype corroded; ca. 19 on body whorl from standard apertural view); teleoconch ornamented by some fine irregular, radial growth lines and stronger, equidistantly-arranged spiral striae; whorls 4, shouldered; aperture not oblique to shell axis from lateral view (although the peristome might be broken); umbilicus very wide; aperture pear-shaped with strongly distinct, relatively narrow sinulus and wider main section; peristome slightly expanded, not reflected; parietal callus strongly protruding, detached from penultimate whorl; upper parietal tooth relatively weak, low, but quite long, reaching peristome, perpendicular to parietal side; palatal tooth relatively strong, situated directly opposite of parietal tooth just at peristome edge.

Measurements (in mm).

H = 0.64, D = 0.74, H/D*100 = 86.5, RUD = 36.3 (holotype).

Differential diagnosis.

In comparison to other Angustopila species possessing two apertural denticles, Angustopila steffeki sp. nov. shows a more depressed shell with a dome-like appearance. Angustopila pallgergelyi has a more conical shell, a lower spire, and denser spiral striation. Angustopila somsaki sp. nov. has a less globular shell, less cylindrical (more funnel-shaped) umbilicus, and a less pointed palatal tooth.

Etymology.

This species is dedicated to and named after Jozef Šteffek (1952-2013), Slovak malacologist.

Distribution.

This species is known from the type locality only in Bolikhamsay Province of Laos (Fig. 48 ).

Figures

Figure 48. Distribution of Angustopila species.

Figure 81. Angustopila steffeki Pall-Gergely & Grego, sp. nov. (holotype, NHMUK 20170296). Apertural (A), ventral (B), lateral (C) and apical (D) sides of the shell; sculpture of the protoconch (E); aperture (F); ventral (G) and frontal (H) surface of the body whorl.