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

Figs 74 , 75 , 76

Type material.

Holotype: Vietnam • 1 empty shell (H: 0.97 mm, D: 1.08 mm); Lạng Sơn Province, Tam Thanh, Núi Vọng Phu, Đ ền Chùa Thư ợng Ngàn (locality code: 2020/57); 21°51.21'N, 106°44.91'E; 250 m a.s.l.; 21 Feb. 2020; A. Hunyadi leg.; HNHM 105298.

Paratypes: Vietnam • 58 shells; same data as for holotype; coll. HA • 569 shells; Lạng Sơn Province, vicinity of Chùa Tam Thanh (locality code: 2020/58); 21°51.35'N, 106°44.81'E; 265 m a.s.l.; 21 Feb. 2020; A. Hunyadi leg.; coll. HA • 10 shells; same data as for preceding; coll. JJV.

Additional material.

Vietnam • 7 j/b shells; same data as for holotype; coll. HA • 115 j/b shells; Lạng Sơn Province, vicinity of Chùa Tam Thanh (locality code: 2020/58); 21°51.35'N, 106°44.81'E; 265 m a.s.l.; 21 Feb. 2020; A. Hunyadi leg.; coll. HA • 1 figured shell (Fig. 76 ); Thanh Hóa Province, Như Thanh District , H ải Vân, Hang Lò Cao Kháng Chiến, vicinity of the cave (locality code: 2020/41); 19°37.08'N, 105°34.63'E; 20 m a.s.l.; 14 Feb. 2020; A. Hunyadi leg.; HNHM 105299 • 7 shells; same data as for preceding; coll. HA .

Diagnosis.

A large, low or high concave-conical Angustopila species with a wide umbilicus, dense spiral striation, and two strong apertural barriers (elevated parietal, elongated or pointed lower palatal).

Description.

Shell large for the genus, wider than high or rarely slightly higher than wide; off-white, concave-conical, shell height highly variable from strongly depressed to triangular, with regularly growing whorls except for the last one; last whorl widest from apertural view; protoconch consists of 1.25-1.5 whorls, spirally striated with the exception of the first whorl; teleoconch with strong, rather dense, irregular radial ribs and equidistantly-spaced, dense spiral striae (ca. 19-21 on body whorl from apertural view); whorls 4-4.25, rounded with tendency towards shouldered contour (in apertural view, the body whorl is slightly pushed from baso-lateral direction); aperture oblique to shell axis in lateral view; umbilicus wide; aperture suboval; peristome expanded, not reflected; parietal callus not detached from penultimate whorl; parietal tooth elevated, straight, starts in some distance from peristome; lower palatal tooth runs parallel with the peristome on the lower 1/2 of the palatal region, in some specimens pointed, in others ridge-like, situated inside from peristome.

Measurements (in mm).

H = 0.85-1.12, D: 1.04-1.14, H/D*100 = 77.3-109.6 (n = 18), RUD = 29.0-33.3 (n = 5).

Differential diagnosis.

Angustopila majuscula sp. nov. is similar to this species by the large shell size, wide umbilicus and the possession of two apertural denticles. However, it has a convex conical shell shape, denser spiral striation and the palatal tooth is situated further up in the aperture. See also under A. pustulata sp. nov.

Etymology.

Named after the palatal tooth that runs parallel with the peristome.

Distribution.

Angustopila parallela sp. nov. is known from two localities in northern Vietnam (Lạng Sơn and Thanh Hóa Provinces) (Fig. 19 ).

Remarks.

Shells from population 2020/57 are generally more depressed than those of 2020/58, although the two groups overlap. The distance between these populations is ca. 300 m (!) in a straight line. Most shells of population 2020/41 possess an elongated palatal tooth, whereas that tooth is pointed in most shells of the other two populations. However, this difference is not exclusive, because there are individuals with a pointed palatal tooth in population 2020/41 and a more elongated tooth in the other two populations. Thus, even if the geographic distance is relatively large overall (ca. 280 km in a straight line), the morphological differences are insufficient to distinguish the population 2020/41 from the other two.

Figures

Figure 19. Distribution of Angustopila species.

Figure 74. Angustopila parallela Pall-Gergely & Hunyadi, sp. nov. A, C-H holotype (HNHM 105298) B paratype. (2020 / 57). Apertural (A, B), lateral (C), apical (D) and ventral (E) sides of the shell; sculpture on the protoconch (F), ventral (G) and frontal (H) surface of the body whorl.

Figure 75. Variability of Angustopila parallela Pall-Gergely & Hunyadi, sp. nov. from the type locality A, B holotype C paratype.

Figure 76. Angustopila parallela Pall-Gergely & Hunyadi, sp. nov. (2020 / 41). Apertural (A), lateral (B), apical (C) and ventral (D) sides of the shell; sculpture on the protoconch with protoconch-teleoconch boundary (E); aperture (F); ventral (G) and frontal (H) surface of the body whorl.