Rishetia kathmandica Budha & Backeljau

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

Rishetia kathmandica Budha & Backeljau sp. n. Figs 2E, 7, 13B

Ranibania tenuispira (Benson, 1836): Schileyko and Kuznetsov 1996, p. 158.

Rishetia tenuispira (Benson, 1836): Schileyko 1999, p. 533.

Rishetia tenuispira (Benson, 1836): Budha et al. 2015, p. 17.

Material examined.

Holotype. CDZMTU062P/1 specimen (dissected), Godawari Botanical Garden, Lalitpur, 1453-1550 m, 27.600013N, 85.398443E, 30.IV.2007, leg. P.B. Budha and R. Devkota. Paratypes: CDZMTU62/20 shells and CDZMTU063P/2 specimens (one dissected) from the type locality (same data as holotype). Paratypes: CDZMTU062b/40 shells and CDZMTU062P/7 specimens, Godawari Botanical Garden, Lalitpur, 1453 m, 27.596657N, 85.381392E, 03.IX.2008, leg. P.B. Budha. Paratypes: CDZMTU064/40 shells and CDZMTU064P/12 specimens (3 dissected), Nagarjun Forest, Balaju, Kathmandu, 1600 m-1800 m, 27.739058N, 85.297854E, 02.X.2008, leg. S. Khatiwara and S. Khanal. Glessula sp. Nagarkot, Nepal, A. Comfort 1989, one shell at NHM, London (general collection, non-type). Rishetia tenuispira (Benson, 1836). In addition, one photograph of two shells (Fig. 14D): ZMMU, Lc. 34221, Raniban Range, Nagarjun Royal Forest, Balaju, Kathmandu, Nepal, 1480 m, leg./det. A.G. Kuznetsov, 28.04.1995; ZMMU, Lc. 34222, 1600-1800 m, leg./det. A.G. Kuznetsov, 28+30.04.1996.

Distribution.

Nepal.

Etymology.

The name refers to the hill forests of Kathmandu valley from where the specimens were collected.

Shell.

Measurements (n = 17): SH 24.8-41.1 mm, SW 7.8-9.3 mm, HA 7.1-8.5 mm, WA 4.1-5.4 mm, Wh 11.0-13.0; holotype: SH 28.1 mm, SW 8.1 mm, HA 7.1 mm, WA 4.1 mm, Wh 12; approx. 4 × higher than wide, elongately turreted, colour ruddy, regularly sculptured. The first whorl pointed (Fig. 2E1) with distinct and regular radial riblets, more prominent on the first few whorls, ribs much stronger towards the suture; middle whorls of the shell show incised radial striation. Suture shallow, sides moderately flat. Aperture small, oval, 1.6 × higher than wide, peristome thin, columellar margin slightly convex, thinly calloused, white.

Radula

(Fig. 13B). Central tooth very small, lacks cusps, lateral teeth tricuspid.

Animal

(Fig. 14E). Grey black, with dark tentacles. Body minutely papillate. The sole is lighter than the body.

Genitalia

(n = 5) (Fig. 7 A–B). The flagellum is a long cylindrical sac; the epiphallic caecum is a simple sac, shorter than the flagellum. Penis cylindrical and longer than the epiphallus. The penial retractor muscle far apart from the flagellum. Interior wall of the penis with distinct rectangular zigzag folds (Fig. 7A). Three specimens contained 12-14 juvenile shells in the spermoviduct. Vagina about as long as the penis. Gametolytic sac pear shaped with a neck that is not distinct from the Gametolytic duct. Hermaphroditic duct is connected closer towards the free end of the albumen gland.

Remarks.

Schileyko and Kuznetsov (1996) initially described this species as Ranibania tenuispira (Benson, 1836) (collected from Raniban forest, Balaju, Kathmandu, Nepal). Later Schileyko (1999) referred the species to as Rishetia tenuispira (Benson, 1836). However, the shells of Nepalese " R. tenuispira " do not match with: (1) the possible syntype of Subulina tenuispira Benson, 1836 at UMZC l.102045, type locality labelled as 'Teria Ghat’, because this syntype has a blunt first whorl (Fig. 14A), (2) Achatina tenuispira Benson, 1836 shells in the MacAndrew collection from the W. Khasi hills (India) at the NHMUK, London, Acc. No. 1582.03.VII.I (Fig. 14C), and (3) 33 syntypes of Glessula (Rishetia) longispira Godwin-Austen, 1920 from Rishetchu, Sikkim, India NHMUK, Reg. No. 1903.7.1.552, because these syntypes have a blunt first whorl and comparatively very slender shell (Fig. 14B). Therefore we here describe Nepalese " R. tenuispira " as the new species R. kathmandica . The genitalia of this new species are similar to those of R. longispira , but R. kathmandica sp. n. has a relatively longer vagina (Fig. 7B, C). R. kathmandica sp. n. is common in mixed Quercus-Rhododendron forests between 1400 m and 2000 m in the hills around Kathmandu valley. The general collection of NHM, London contains a single shell of R. kathmandica sp. n. from Nagarkot, Nepal, labelled as Glessula sp.