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

Fig. 87

Type material.

Holotype: Vietnam • 1 empty shell (H: 0.87 mm, D: 0.81 mm); Sơn La Province, Quỳnh Nhai district, 20 km north from crossing point to Thuận Châu, Chiềng Khoang, cave above the village (locality code: 2020/9); 21°33.44'N, 103°40.91'E; 315 m a.s.l.; 7 Feb. 2020; A. Hunyadi leg.; HNHM 105317.

Paratypes: Vietnam • 4 shells; same data as for holotype; coll. HA.

Diagnosis.

A medium-sized, conical Angustopila species with three prominent apertural barriers (long parietal tooth reaching parietal callus, prominent lower palatal tooth, prominent subcolumellar tooth).

Description.

Shell of normal size for the genus, slightly higher than wide; off-white, translucent; conical with regularly growing whorls; body whorl widest in standard apertural view; protoconch consists of 1.5 whorls, with slight spiral striation on the last protoconch whorl; teleoconch with some strong to weak radial striae, occasionally grouped in multiple thread-like lines between stronger radial growth lines and spiral striae (ca. 12-14 on body whorl from standard apertural view) of comparable strength, resulting in a reticulated sculpture; whorls 4.25-4.5, rounded; aperture slightly oblique to shell axis in lateral view; umbilicus wide; aperture broad piriform-subquadrate with straight concave parietal part; peristome expanded, not reflected; parietal callus not detached from penultimate whorl; parietal tooth large and straight, directed towards lower palatal tooth; anterior to large parietal tooth (on the parietal callus) the callus is supported with a whitish triangular thickening facing to the front; palatal tooth situated on lower part of palatal wall (probably homologous with the lower palatal tooth), small, denticle-like, sits close to basal lip; subcolumellar tooth situated at junction of columellar and basal positions, similar in size and alignment to the peristome edge and in line with the palatal tooth.

Measurements (in mm).

H = 0.87-0.92, D = 0.81-0.86, H/D*100 = 101.2-109.6 (n = 4), RUD = 30.5-30.7 (n = 2).

Differential diagnosis.

No other Angustopila species shows similar arrangement of apertural barriers (parietal + lower palatal + subcolumellar), and the thick callus anterior to the parietal tooth has not been observed in any other congeners. Maybe Angustopila tetradon sp. nov. could be considered as being most similar, but it has an additional upper palatal tooth and a lower conical shell shape. Furthermore, A. rara sp. nov. has a narrower umbilicus, a wider subcolumellar tooth, and a more apically situated palatal tooth.

Etymology.

The specific epithet Angustopila apokritodon derives from the Greek words ἀπόκριτος (= separated) and ὀδούς (= tooth) referring to the large distance between the palatal and subcolumellar teeth.

Distribution.

This species is only known from the type locality in Sơn La Province in Vietnam (Fig. 27 ).

Figures

Figure 27. Distribution of Angustopila species.

Figure 87. Angustopila apokritodon Pall-Gergely & Hunyadi, sp. nov. A paratype B-I holotype (HNHM 105317). Apertural (A, B), lateral (C), apical (D) and ventral (E) sides of the shell; sculpture of the protoconch with protoconch-teleoconch boundary (F); aperture (G); ventral (H) and frontal (I) surface of the body whorl.