Angustopila akrodon Pall-Gergely & Hunyadi sp. nov.

Fig. 60

Type material.

Holotype: Vietnam • 1 empty shell (H: 0.88 mm, D: 0.87 mm); Thanh Hóa Province, Như Thanh District, 600 m south from Xuân Khang along road no. 45, around the cave temple (locality code: 2020/40); 19°40.35'N, 105°31.07'E; 80 m a.s.l.; 14 Feb. 2020; A. Hunyadi leg.; HNHM 105293.

Paratypes: Vietnam • 16 shells; same data as for holotype; coll. HA.

Diagnosis.

A medium-sized, concave-conical Angustopila species with a wide umbilicus, dense spiral striation, a prominent palatal and a highly situated upper parietal tooth.

Description.

Shell of normal size for the genus, higher than wide, or rarely slightly wider than high; off-white, concave-conical; body whorl widest from standard apertural view; protoconch consists of 1.25 whorls, with very slight indication of spiral striation preceding the first teleoconch whorl; teleoconch with fine, dense, irregularly spaced radial growth lines and much stronger, equidistantly-arranged dense spiral lines (ca. 16-20 on body whorl from standard apertural view); whorls 4.5, slightly shouldered; aperture oblique to shell axis from lateral view; umbilicus moderately wide; aperture pear-shaped with a parabolic sinulus caused by alignment of the parietal and upper palatal tooth; peristome expanded, not reflected; parietal callus protruding, detached from penultimate whorl; parietal tooth straight, strong but short, almost reaching peristome edge; upper palatal tooth situated very high in the aperture, points in direction of parietal tooth, blunter and wider than parietal tooth.

Measurements (in mm).

H = 0.88-1.04, D = 0.86-0.91, H/D*100 = 98.9-118.2 (n = 5), RUD = 26.4-27.3 (n = 2).

Differential diagnosis.

Angustopila akrodon sp. nov. differs from the much larger A. majuscula sp. nov. in the concave-conical shell shape, the blunter apex, denser spiral striation and the narrower sinulus. Angustopila concava is larger, it has a more oblique aperture and a weaker parietal tooth and lacks a palatal tooth.

Etymology.

The upper parietal tooth is situated very high compared to other species with two apertural teeth (ἄκρον = highest, ὀδούς = tooth in Greek).

Distribution.

Angustopila akrodon sp. nov. is known from the type locality only in Thanh Hóa Province of northern Vietnam (Fig. 31).