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).