Angustopila huoyani Jochum, Slapnik & Pall-Gergely , 2014

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 huoyani Jochum, Slapnik & Pall-Gergely, 2014

Figs 66 , 67

Angustopila huoyani Jochum, Slapnik & Páll-Gergely in Jochum et al. 2014: 27, figs 4, 5, video 1.

Angustopila huoyani - Páll-Gergely et al. 2015a: 39, fig. 3.

Type locality.

"China, Hunan, Longshan (龙山县), Huoyan (火焰), Feihu Dong (飞虎洞), (29°12.53'N, 109°18.37'E, 550 m alt.)".

Type material examined.

Holotype: China • 1 shell; Hunan, Longshan, Huoyan, Feihu Dong ("Cave of the Wild Tiger"), Kitajska; 13 Apr. 1997; Verovnik leg.; MCSMNH 50312/1.

Paratypes: China • 1 shell; same data as for holotype; MCSMNH 50312/2-3 • 3 shells; same data as for holotype; MCSMNH 50312/4-6 • 2 shells; same data as for holotype; MCSMNH 50312/7-9.

Additional material examined.

China • 65 complete shells; same data as for holotype; MCSMNH 50312 (separated into 4 vials based on morphological groups, see remarks) • 48 broken shells (in 2 vials); same data as for holotype; MCSMNH 50312.

Diagnosis.

A medium-sized to large, conical-globular Angustopila species with a very narrow umbilicus, a parietal tooth, and an upper palatal tooth.

Differential diagnosis.

The morphologically closest congener with two apertural denticles is A. tamlod known from Thailand; however, Angustopila huoyani is tightly coiled, has a more conical shell, bears more pronounced apertural dentition, and has stronger and denser spiral striation. The shell of A. dominikae is more compact and is 2/3 the size of A. huoyani . Though also bearing two denticles, A. uvula sp. nov. is comparatively loosely coiled, has larger whorls, a bulbous protoconch and a slightly downwards directed tuba and bears a very prominent parietal denticle opposed by a weak palatal one. Angustopila bidentata sp. nov. has a narrower umbilicus and more oblique aperture. Angustopila erawanica sp. nov. has a more horizontally oriented aperture that is impressed at the parietal lamella.

Measurements (in mm).

H = 0.96-1.31; D = 0.82-1.1, H/D*100 = 109.1-143.6 (n = 67), RUD = 14.3-18.8 (n = 6).

Distribution.

This species is known from two caves, one located in Guangxi, and the other in Hunan, China (Fig. 19 ).

Remarks.

The original description of the type material describes the holotype and eight paratypes. However, results in Jochum et al. (2014: table 2) were based on 30 specimens. For this revision, and because we intended to re-investigate this species and compare it with other congeners, we borrowed the type material of A. huoyani from its home museum in Ljubljana. The examination revealed that in addition to the holotype and the paratypes, there were 65 shells (previously unknown to Jochum et al. 2014) in perfect condition and several others that were somewhat damaged. The 65 shells showed extraordinary variation in terms of shell size and shape, while the positions of the apertural teeth and the sculpture did not vary. At first sight, the shells could be separated into four more or less clearly distinguishable groups as follows: (1) shell large, rounded, aperture ovoid, whorls: 4.75-5.5 (mean: 5.15); (2) shell large, with many whorls, aperture depressed (narrow), whorls: 5.5-6.5 (mean: 5.89) (3) shell very slender, aperture ovoid, whorls: 5-6 (mean: 5.47); and (4) shell small, rounded, aperture ovoid, whorls: 4.75-5.5 (mean: 5.26). After we measured all shells, it became evident that none of these groups are distinct based on shell measurements alone (see Fig. 67 ). Although the grouping of the shells into morphological groups was possible using a stereo microscope, these do not likely belong to a biologically distinct species. It is, however, possible that the soil sample containing all A. huoyani shells originated from multiple subpopulations living under different environmental conditions. Thus, the extreme variability we observed is explained by phenotypic plasticity.

Measurements of the holotype (H: 1.14 mm, D: 0.94 mm) differ from those published in the original description (H: 1.09 mm, D: 0.87 mm).

Figures

Figure 19. Distribution of Angustopila species.

Figure 66. Angustopila huoyani Jochum, Slapnik & Pall-Gergely, 2014 (holotype, MCSMNH 50312 / 1). Apertural (A), apical (B), lateral (C) and ventral (D) sides of the shell; sculpture on the protoconch (E), aperture (F); ventral (G) and frontal (H) surface of the body whorl.

Figure 67. Conchological variability (upper plate) and Shell diameter (x axis, in mm) vs. shell height (y axis, in mm) (lower diagram) of Angustopila huoyani Jochum, Slapnik & Pall-Gergely, 2014. Group 1 (A, B), Group 2 (C, D), Group 3 (E, F), Group 4 (G, H). Group 1 (dot), Group 2 (circle), Group 3 (empty square), Group 4 (filled square).