Dicharax verrucosus Páll-Gergely & Hunyadi, 2021

Páll-Gergely, Barna, Hunyadi, András, Grego, Jozef, Reischütz, Alexander & Auffenberg, Kurt, 2021, Nineteen new species of Alycaeidae from Myanmar and Thailand (Gastropoda: Caenogastropoda: Cyclophoroidea), Zootaxa 4973 (1), pp. 1-61 : 44-45

Dicharax verrucosus Páll-Gergely & Hunyadi n. sp.

Fig. 34

Material examined. Holotype: Myanmar, Shan State, Taunggyi, hill above Aye Say Tee Pagoda, Dragon Cave , 20°47.489’N, 97°03.036’E, 1380 m a.s.l. (locality code: 2018/44), 08 Oct. 2018, A. Hunyadi, K. Okubo & J.U. Otani leg., HNHM 104862 (holotype: D: 2.83 mm, H: 2.14 mm) . Paratypes: 10 shells, same data as holotype, HA . Other material: 2 shells, Myanmar, Shan State, Hsihseng centre E ca. 6 km, right side of rd. + 400 m on unpaved rd., limestone hill, 20°7.983’N, 97°18.145’E, 1010 m a.s.l. (locality code: 2018/40), 07 Oct. 2018, A. Hunyadi, K. Okubo & J.U. Otani leg., HA .

Etymology. The specific epithet verrucosus (Latin for excrescence/wart) refers to the small swelling on R3, reminiscent of a wart.

Diagnosis. A Dicharax species with a relatively high spire, glossy, smooth R1, R2+R3 about a quarter whorl (R3 shorter than R2), and blunt swelling on R3.

Description. Shell light grey, possibly translucent when fresh; shell outline rounded in dorsal view, spire elevated, body whorl rounded; protoconch low, rather glossy, 1.5 whorls; R1 approximately 2.25 whorls, smooth, glossy, with occasional, weak growth lines; boundary between R1 and R2 conspicuous due to dense R2 ribs; R2 ribs curved toward aperture, ca. 36–38 R2 ribs present; R2 ribs situated close to each other, spaces between ribs much less than rib width; R2+R3 covers ca. quarter whorl; R3 very short; about half as long as R2; sculpture of R3 similar to R1, boundary between R2 and R3 distinct, indicated by deep constriction; middle of R3 with prominent, blunt swelling; aperture slightly oblique to shell axis; rounded, with slight upper incision in parieto-palatal region; boundary between inner and outer peristomes distinct, especially at columellar portion; inner peristome slim, slightly protruding, outer peristome strongly thickened, expanded and reflected, especially toward umbilicus (in sample 2018/40 more conspicuously than in 2018/44); umbilicus relatively narrow, less than a third of shell width.

Measurements. D: 2.76–3.24 mm, H: 2.1–2.46 mm (2018/44); D: 3.21–3.55 mm, H: 2.46–2.5 mm (2018/40).

Operculum. Unknown.

Differential diagnosis. The combination of the elevated spire, smooth R2, short R3 with a prominent swelling distinguishes this species from all congeners.

Distribution. Both known populations occur in the southeastern part of Shan States, Myanmar. The straightline distance between the two is ca. 77 km ( Fig. 17 ).

Remarks. The typical shells from Taunggyi are slightly smaller, and have less reflected peristomes than specimens from Hsihseng. However, since all other shell characters (shape, ratios of the shell regions, and shell sculpture) are identical, we treat them as the same species.

Figures

FIGURE 17. Distribution of alycaeid species in northern Thailand and Myanmar. filled circle: Dicharax admirandus Páll- Gergely & Auffenberg, n. sp., empty square: Dicharax ebrius Páll-Gergely & Auffenberg, n. sp., filled triangle: Dicharax gnomus Páll-Gergely, n. sp., filled square: Dicharax mirounga Páll-Gergely, n. sp., inverted empty triangles: Dicharax verruco- sus Páll-Gergely & Hunyadi n. sp., rhombus: Dicharax stuparum Páll-Gergely & Hunyadi, 2018, empty triangle: Metalycaeus anas Páll-Gergely & A. Reischütz, n. sp.

FIGURE 34. Dicharax verrucosus Páll-Gergely & Hunyadi n. sp., A: holotype (HNHM 104862), B: specimen from sample 2018/40 (coll. HA).