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

Fig. 83

Type material.

Holotype: Vietnam • 1 empty shell (H: 0.9 mm, D: 0.81 mm); Sơn La Province, 10 km from centre of Mộc Châu towards Sơn La, right side of road no. 6, south of Tất Ngoằng (locality code: 2020/5); 20°52.58'N, 104°35.34'E; 715 m a.s.l.; 5 Feb. 2020; A. Hunyadi leg.; HNHM 105314.

Paratypes: Vietnam • 13 adult shells; same data as for holotype; coll. HA.

Additional material.

Vietnam • 1 j/b shell; same data as for holotype; coll. HA.

Diagnosis.

A medium-sized Angustopila species with a conical (very slightly conical-globular) shell, a strong parietal tooth reaching the peristome edge, and an upper palatal tooth of comparable height.

Description.

Shell of normal size for the genus, higher than wide; off-white, translucent, conical to very slightly conical-globular; body whorl widest in standard apertural view; protoconch consists of 1.5 whorls with rather weak spiral striation preceding the first teleoconch whorl; teleoconch with very fine irregularly spaced, weak radial growth lines crossed by much stronger irregularly and sparsely-spaced spiral striae (ca. 11-14 on body whorl from apertural view); on both ventral and dorsal surfaces of body whorl spiral lines dominant or spiral and radial lines are of comparable strength; whorls 4-4.25, rounded or very slightly shouldered; aperture slightly oblique to shell axis from lateral view; umbilicus moderately wide; aperture reniform, sinulus relatively narrow and isolated due to the pronounced parietal and palatal teeth; peristome expanded, not reflected; parietal callus protruding, detached from penultimate whorl (aperture not adnate); parietal tooth elevated, strong, but short, reaches parietal callus, perpendicular to parietal wall; palatal tooth almost as high as parietal one, situated near peristome edge, at middle of palatal region, just opposite of parietal tooth.

Measurements (in mm).

H = 0.86-0.9; D = 0.81-0.85, H/D*100 = 102.4-111.1 (n = 4), RUD = 26.5-28.4 (n = 2).

Differential diagnosis.

Angustopila tweediei sp. nov. is most similar to A. bathyodon sp. nov. in terms of shell size and shape, and the position of apertural barriers. However, the spire of the latter species is lower, and both parietal and palatal teeth are situated much deeper inside the aperture. Angustopila reticulata sp. nov. is similar in general shell shape and size and the formation of the apertural barriers. However, it has a thicker peristome, a protruding palatal lip anterior to the palatal tooth, a rather reticulated superficial sculpture (i.e., the radial lines are strong), and slightly wider umbilicus. The apertural denticles of A. huoyani are similar, but that species is much larger, has more whorls, and a more horizontally oriented aperture than this new species.

Etymology.

This new species is dedicated to and named after Michael W.F. Tweedie (1907-1993), English naturalist and malacologist, who pioneered collecting Southeast Asian land snails via sediment sampling methods ( Tweedie 1961).

Distribution.

This species is known from the type locality only (Fig. 27 ).

Figures

Figure 27. Distribution of Angustopila species.

Figure 83. Angustopila tweediei Pall-Gergely & Hunyadi, sp. nov. A paratype B-I holotype (HNHM 105314). Apertural (A, B), lateral (C), apical (D) and ventral (E) sides of the shell; sculpture on the protoconch (F); aperture (G); ventral (H) and frontal (I) surface of the body whorl.