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

Figs 79 , 80

Type material.

Holotype: Thailand • 1 empty shell (H: 0.66 mm, D: 0.78 mm); Chiang Mai Province, northeastern part of Doi Chiang Dao, Wat Tham Chiang Dao northwest 2 km (locality code: 2015/6); 19°24.02'N, 98°54.68'E; 835 m a.s.l.; 7 Feb. 2015; A. Hunyadi leg.; CUMZ 7440.

Paratypes: Thailand • 1 shell; same data as for holotype; NMBE 550642 • 9 shells; same data as for holotype; coll. HA • 3 shells; Chiang Rai Province, 7 to 9 km SSW of Mae Sai, around Wat Tham Pla (locality code: 2015/18); 20°19.72'N, 99°51.82'E; 400 m a.s.l.; 12 Feb. 2015; A. Hunyadi leg.; coll. HA • 7 shells; Chiang Rai Province, 6 km S of Chiang Khian, toward Pa Ngae, Wat Phra That Charui (locality code: 2015/20); 19°34.41'N, 99°59.19'E; 420 m a.s.l.; 13 Feb. 2015; A. Hunyadi leg.; coll. HA • 1 imaged shell; same data as for preceding; HNHM 103480.

Additional material.

Thailand • 2 juvenile shells; same data as for holotype; coll. HA .

Diagnosis.

A small, depressed-globular Angustopila species with domed dorsal side, a pear-shaped aperture having an apertural axis nearly parallel to shell axis, a strong parietal tooth, and a very weak upper palatal tooth.

Description.

Shell small for the genus, wider than high; off-white, depressed globular with domed dorsal side; body whorl widest from standard apertural view; protoconch consists of 1.25 whorls with four spiral striae; teleoconch ornamented by fine radial growth lines and stronger, equidistantly- arranged spiral striae (ca. 12-20 on body whorl from standard apertural view); whorls 3.5, slightly shouldered; aperture slightly oblique to shell axis from lateral view; umbilicus very wide and perspectival; aperture pear-shaped with slight indentation at the parietal side; apertural axis and shell axis join under a small angle (nearly parallel with each other); sinulus relatively wide; peristome expanded, not reflected; parietal callus strongly protruding slightly beyond width of penultimate whorl, visible even from lateral view behind palatal peristome, detached from penultimate whorl; irregular parietal tooth relatively weak, low, but quite long, nearly reaching peristome, oblique to parietal side (joins at an angle less than 90 degrees); upper palatal tooth very weak and low, situated on opposite side to parietal tooth, and set in some distance from peristome.

Measurements (in mm).

H = 0.62-0.67, D = 0.75-0.8, H/D*100 = 80-89.5 (n = 9), RUD = 32.9-37.8 (n = 4).

Differential diagnosis.

Angustopila pallgergelyi has a deeper parietal incision and a stronger (more elevated and pointed) upper palatal tooth. See under A. maasseni sp. nov.

Etymology.

The species is dedicated to Prof. Somsak Panha (Chulalongkorn University, Thailand) to acknowledge his work, which resulted in the discovery of numerous new invertebrate species in Southeast Asia and initiated the careers of many young taxonomists.

Distribution.

This species is known from three localities in Chiang Mai and Chiang Rai Provinces in northern Thailand. The largest distance between the localities is ca. 145 km (Fig. 55 ).

Remarks.

Although some small differences could be determined between the two figured shells deriving from two different localities, we found no notable conchological differences between the three populations.

Figures

Figure 55. Distribution of Angustopila species.

Figure 79. Angustopila somsaki Pall-Gergely & Hunyadi, sp. nov. (holotype, CUMZ 7440). Apertural (A), ventral (B), lateral (C) and apical (D) sides of the shell; aperture (E, F); sculpture of the protoconch (G), ventral (H) and frontal (I) surface of the body whorl.

Figure 80. Angustopila somsaki Pall-Gergely & Hunyadi, sp. nov., sample 2015 / 20, HNHM 103480. Apertural (A), ventral (B), lateral (C), and apical (D) sides of the shell; sculpture of the protoconch (E); aperture (F); ventral (G) and frontal (H) surface of the body whorl.