Rishetia cf. mastersi Godwin-Austen, 1920

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 : 134-135

Rishetia cf. mastersi Godwin-Austen, 1920 Figs 2F, 8A

Glessula (Rishetia) mastersi Godwin-Austen, 1920: Godwin-Austen 1920, p. 46, pl. 161, fig. 14., pl. 162, fig. 22.

Glessula mastersi Godwin-Austen, 1920: Ramakrishna et al. 2010, p. 166.

Material examined.

CDZMTU065/5 shells, Kurintar, Chitwan, degraded riverine bushes with big boulders, mixed Shorea robusta forest, 420-527 m, 27.875820N, 84.589321E, 25.X.2008, leg. P.B. Budha. CDZMTU065b/16 shells and CDZMTU065P/1 specimen (dissected), Kurintar, Chitwan, 527 m, 27.874143N, 84.586683, 23.VII.2010, leg. P.B.Budha.

Shell.

Measurements (n = 30): SH 13.0-19.0 mm, SW 5.4-6.3 mm, HA 5.0-6.1 mm, WA 2.7-3.5 mm, Wh 8.5-9.5; approx. 2.7 × higher than wide, oblong turreted, yellowish brown. Surface with shallow radial ribs, stronger towards the suture, sculpture regular, thin transparent periostracum. Suture deep, spire convex. The first whorl rounded (Fig. 2F1). Aperture small and ovate, 1.7 × higher than wide, peristome thin, columellar margin short and abruptly truncated.

Genitalia

(n = 2) (Figs 8A). Vas deferens long with a constant diameter. The flagellum is a simple sac. Epiphallic caecum is longer than the flagellum. Epiphallus much shorter than the penis. The penial retractor muscle far apart from the flagellum. Gametolytic duct slender, ending into a balloon-like gametolytic sac, which is slightly longer than the gametolytic duct. Vagina as long as the penis. Interior wall of the penis with a strong fold.

Remarks.

A single specimen of Rishetia sp. was collected from the Shorea robusta forest at Bosikharka, Dhanding (CDZMTU078P). Its shell is similar to R. mastersi Godwin-Austen, 1920, but it is slightly smaller and has relatively stronger radial ribs. The shape of its flagellum and epiphallus is similar to that of R. mastersi too (Figs 8A, 8C), but the interior of its penis shows three longitudinal folds (Fig. 8D), whereas in R. mastersi there is only one longitudinal fold (Fig. 8B).