Angustopila margaritarion 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 margaritarion Pall-Gergely & Hunyadi sp. nov.

Fig. 47

Type material.

Holotype: Laos • 1 empty shell; Luang Namtha Province, 19.8 km southeast from centre of Vieng Phou Kha, south from Ban Phou Lek, southern edge of quarry (locality code: 2019/122); 20°32.54'N, 101°07.96'E; 780 m a.s.l.; 8 Oct. 2019; A. Hunyadi leg.; HNHM 105288.

Paratypes: Laos • 3 shells; same data as for holotype; coll. HA • 3 shells; Luang Namtha Province, 43.8 km from centre of Luang Namtha towards Vieng Phou Kha, Phou Lan, 100 m from left side of road (locality code: 2019/123); 20°44.53'N, 101°11.10'E; 770 m a.s.l.; 8 Oct. 2019; A. Hunyadi leg.; coll. HA.

Diagnosis.

A medium-sized Angustopila species with a conical-globular shell, few (ca. 3.75) whorls, glossy shells with very weak spiral striation, a strongly thickened peristome, and an elevated, club-shaped parietal tooth.

Description.

Shell of normal size for the genus, slightly higher than wide; conical-globular; body whorl widest in standard apertural view; protoconch consists of ca. 1.25 whorls (although the protoconch-teleoconch boundary is not clearly discernible), with very weak spiral striation; teleoconch glossy, with extremely fine growth lines and very weak spiral striae (ca. 14 on body whorl from apertural view); on both ventral and dorsal surfaces of body whorl spiral lines dominant; whorls 3.75-4, slightly shouldered; aperture slightly oblique to shell axis from lateral view; umbilicus moderately narrow; aperture ovate-oblong with a straight parietal callus; sinulus very wide, isolated due to elevated parietal tooth; peristome expanded, not reflected; parietal callus only very slightly detached from penultimate whorl; parietal tooth elevated, high, with club-shaped cross sectional view, perpendicular to parietal wall or slightly bent towards columella.

Measurements (in mm).

H = 0.87-0.96, D = 0.79-0.84, H/D*100 = 107.4-114.3 (n = 6), RUD = 23.8-27.5 (n = 3).

Differential diagnosis.

Angustopila margaritarion sp. nov. lives sympatrically with A. fabella , which is larger, has a conical (instead of conical-globular) shell, has a matt shell surface, stronger spiral striation, and more slender parietal tooth. See also under A. vandevenderi sp. nov. and A. vitrina sp. nov.

Etymology.

The glossy shell resembles a tiny pearl (μαργαριτάριον in Greek). The specific epithet is to be used as a noun in apposition.

Distribution.

This new species is known from two nearby localities (ca. 23 km between them in a straight line) in Luang Namtha Province, northern Laos (Fig. 48 ).

Figures

Figure 47. Angustopila margaritarion Pall-Gergely & Hunyadi, sp. nov., paratype (A) and holotype (HNHM 105288) (B-I). Apertural (A, B), lateral (C), apical (D) and ventral (E) sides of the shell; aperture (G), microstructure of the protoconch (F), ventral (H) and frontal (I) surface of the body whorl.

Figure 48. Distribution of Angustopila species.