Angustopila hyron Pall-Gergely & Vermeulen, 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 hyron Pall-Gergely & Vermeulen sp. nov.

Fig. 89

Type material.

Holotype: Vietnam • 1 empty shell (H: 0.8 mm, D: 0.8 mm); Quang Ninh Province, Halong Bay area, unnamed island in Dau Moi Temple area (locality code: WMVT.0338); 20°55.69'N, 107°09.40'E; 13 Sep. 2003; W.J.M. Maassen leg.; RMNH.5006716.

Paratypes: Vietnam • 22 shells; Quang Ninh Province, Halong-Campha area, 4.5 km SW Quang Hanh (locality code: JJV6229); 20°58.98'N, 107°11.83'E; 29 Sep. 1998; J.J. Vermeulen & A.J. Whitten leg.; JJV6229 • 2 shells, same data as for preceding; coll. HA.

Additional material.

Vietnam • 1 shell (has only a palatal tooth and appears to be more triangular); same data as for holotype; RMNH.347776.

Diagnosis.

A small Angustopila species with a domed, conical-globular shell, strong parietal tooth, and two deeply set upper palatal and subcolumellar teeth.

Description.

Shell small for the genus, slightly higher than wide or slightly wider than high; colourless, translucent when fresh, dorsal side conical-globular to domed; body whorl widest in standard apertural view; protoconch consists of 1.5 whorls, with very slight indication of spiral striation preceding the first teleoconch whorl (visible only from lateral, not apical view); teleoconch weakly sculptured by some fine radial growth lines and much stronger, equidistantly-arranged spiral striae (ca. 16 on body whorl from standard apertural view); whorls 4, very slightly shouldered; aperture slightly oblique to shell axis from lateral view; umbilicus wide; aperture pear-shaped, sinulus wide; peristome expanded, not reflected; parietal callus protruding, detached from penultimate whorl; parietal tooth strongly developed, high, perpendicular to parietal side; upper palatal tooth weak, low, deeply-set; subcolumellar tooth also weak, blunt, also situated inside some distance from peristome.

Measurements (in mm).

H = 0.77-0.83, D = 0.75-0.86, H/D*100 = 91.9-106.7 (n = 7), RUD = 31.3-32.9 (n = 3).

Differential diagnosis.

Angustopila hyron sp. nov. can be distinguished from all other Angustopila species based on the depressed conical-globular shell, the domed form, and the three apertural teeth. The most similar and geographically close, A. quadridens sp. nov., is larger, has stronger spiral striation and bears four teeth, which are more pronounced than those in A. hyron sp. nov. Although Angustopila coprologos uninodus ssp. nov. also bears three denticles, it differs from A. hyron in that it is smaller, more depressed, and has a more prominent sculpture.

Etymology.

The specific epithet Angustopila hyron (Greek: beehive) refers to the shape of the shell, and to be used as a noun in apposition.

Distribution.

This species is known from two geographically adjacent sites in Halong Bay, northern Vietnam (Fig. 24 ).

Figures

Figure 24. Distribution of Angustopila species in the Halong Bay area.

Figure 89. Angustopila hyron Pall-Gergely & Vermeulen, sp. nov. (holotype, RMNH. 5006716). Apertural (A), ventral (B), apical (C) and lateral (D) sides of the shell; sculpture of the protoconch (E), aperture (F); ventral (G) and frontal (H) surface of the body whorl.