Rishetia rishikeshi Budha & Naggs

Budha, Prem B., Naggs, Fred & Backeljau, Thierry, 2017, Conchological differentiation and genital anatomy of Nepalese Glessulinae (Gastropoda, Stylommatophora, Subulinidae), with descriptions of six new species, ZooKeys 675, pp. 129-156 : 136-137

Rishetia rishikeshi Budha & Naggs sp. n. Figs 2I, 10, 13C

Material examined.

Holotype: CDZMTU070P/1 specimen, Jhawalepakho Community Forest near Rishikesh Temple, Ridi, Gulmi District, montane hill Shorea robusta forest, 832 m, 27.932775N, 83.436552E, 06.IX.2006, leg. P.B. Budha. Paratypes: CDZMTU071/11 shells from the type locality (same data as holotype).

Distribution.

Only reported from the type locality.

Etymology.

The species name refers to the famous Rishikesh Hindu Temple at Ridi, Gulmi District.

Shell.

Measurements (n = 10): SH 12.1-16.2 mm; SW 4.6-5.7 mm; HA 4.0-5.5 mm; WA 2.5-3.4 mm; Wh 8.0-9.3; holotype: SH 14.1 mm; SW 5.3 mm; HA 4.4 mm; WA 2.6 mm; Wh: 9.2; approx. 2.6 × higher than wide, oblong turreted, yellowish brown. Surface with regular, dense, radial ribs towards the suture. Suture deep, spire convex. Aperture small and ovate, 1.7 × higher than wide, peristome thin, columellar margin abruptly truncated.

Radula

(Fig. 13C). Central tooth very small, lateral teeth tricuspid with the central cusp bifurcated.

Animal

(Fig. 14E). Dark grey with a heavily papillated body. The foot is light, showing weak transverse lines on the sole.

Genitalia

(n = 2) (Figs 10 A–B). Vas deferens with a constant diameter over its entire length. Epiphallic caecum nearly as long as the flagellum. Epiphallus long, but shorter than the penis. The penial retractor muscle far apart from the flagellum. Vagina as long as the penis. Gametolytic sac is nearly round, separated by a neck from the gametolytic duct. Albumen gland very small in the dissected specimens. The internal surface of the penis smooth with several longitudinal convoluted folds (Fig. 10B).

Remarks.

R. rishikeshi sp. n. was collected from the western side of Kaligandaki River. Conchologically, this new species is similar to R. mastersi Godwin-Austen, 1920 of Assam, NE India ( Godwin-Austen 1920, p. 46, pl. 162, fig. 3). But the flagellum and epiphallic caecum are comparatively very short in R. rishikeshi sp. n. Similarly the interior of the penis in R. rishikeshi sp. n. contains several convoluted folds while in R. mastersi there is only one strong and straight fold.