India, Bangladesh, Sri Lanka, Nepal, China, Myanmar, Borneo, Sumatra, Java, Thailand and Vietnam (Gude 1914, Panha 1995-1996, Schileyko 2011).

Achatina ceylanica L. Pfeiffer, 1845

Shell ovate-conic or turreted, glossy in general, with or without spiral lirae on the first 1-2 whorls, first whorl rounded, body whorl broad, columella truncated. Vagina shorter than penis. The proximal part of male reproductive organ varies with respect to the form of the flagellum, i.e. from a comb-like structure with many notches, to a hand-like structure with two or more finger-like processes (Figs 3–5).

CDZMTU055/10 shells and CDZMTU055P/2 specimens (dissected), Maipokhari, Ilam, Cryptomeria forest, 2100 m, 27.006944N, 87.93000E, 29.X.2010. leg. P.B. Budha. Glessula orobia var. major Godwin-Austen, 1920: Syntypes NHMUK, Reg. no. 1986020, 2 shells, Richila Peak, Sikkim. G. orobia (Benson, 1860): Syntypes NHMUK, Reg. no. 1946.10.16.82-83, 2 shells, Senchal, Darjeeling, India. G. orobia (Benson), RBINS (I.G. 10591), 2 shells, Darjeeling, India.

“Sinchul et Darjiling (alt. ped. 8500 et 7000, NE India)”.

Nepal and NE India (Godwin-Austen 1920, Kuznetsov and Schileyko 1997, Budha et al. 2015).

Shell. Measurements (n = 6): SH 7.0–8.5 mm, SW 4.0–4.5 mm, HA 3.0–3.5, WA 2.0–2.5, Wh 6.0–7.0; approx. 1.8× higher than wide, thin, ovate-conic, fresh shells light yellowish, older shells straw coloured. Surface glossy, with widely spaced incised radial striations. The first whorl smooth, second whorl with 10–11distinct fine spiral lirae (Fig. 2A1), other whorls with widely spaced radial striations. Sides convex, suture impressed. Aperture nearly ovate, 1.7× higher than wide, margin simple and thick, columellar margin abruptly truncated, columella slightly curved.

Figure 2. 

Shells (A–K) and SEM micrographs of apical whorls (A1–K1) of Nepalese glessulines. A Glessula orobia (Benson, 1860): CDZMTU055P, shell of dissected specimen, Maipokhari, Ilam, Eastern Nepal BGlessula cf. hebetata: CDZMTU056P, shell of dissected specimen, Godawari, Lalitpur, Central Nepal C G. tamakoshi sp. n., holotype: CDZMTU057P, shell of dissected specimen, Suridobhan, left bank of Tamakoshi River, Dolakha District, Central Nepal D Rishetia hastula (Benson, 1860): CDZMTU059P, shell of dissected specimen, Chitwan National Park, riverine forest opposite bank of Sauraha, Rapti River E R. kathmandica sp. n., holotype: CDZMTU062P, shell of dissected specimen, Godawari Botanical Garden, Lalitpur, Central Nepal FR. cf. mastersi: CDZMTU065P, shell of dissected specimen, Kurintar, Chitwan, degraded riverine bushes with big boulders, mixed Shorea robusta forest G R. nagarjunensis sp. n., holotype: CDZMTU067P, shell of dissected specimen, Nagarjun forest, Balaju-Jamacho trail Nagarjun-Shivapuri National Park, Kathmandu, Nepal H R. rishikeshi sp. n., holotype: CDZMTU0170P, shell of dissected specimen, Jhawalepakho Community Forest, Ridi, Gulmi District, montane hill Shorea robusta forest I Rishetia sp. CDZMTU078P, shell of dissected specimen, Boshikharka, Dhading, Central Nepal J R. subulata sp.n., holotype: CDZMTU072P, shell of dissected specimen, Godawari, along the Godawari-Phulchowki road approx. 200 m above the Naudhara Temple K R. tribhuvana sp. n., holotype: CDZMTU077, shell of dissected specimen, Tribhuvan University garden, Kirtipur, Kathmandu, Nepal.

(n = 2) (Fig. 3). Vas deferens with a constant diameter. The flagellum hand-shaped with five “fingers”. The first “finger” is small and pear-shaped, the fifth “finger” is comparatively short and positioned apart like a thumb (Fig. 3A). Penis cylindrical, basal portion narrower than the proximal portion. The diameters of the gametolytic sac and duct of the dissected specimens were not particularly different. The vagina short, nearly 1/4^th the length of the penis. The penial retractor muscle close to the flagellum. The albumen gland elongated, long, about half of the total length of the spermoviduct. The hermaphrodite duct is very thick.

Figure 3. 

Genitalia of G. orobia: A General view, CDZMTU055P, Maipokhari, Ilam, Eastern Nepal B var. major reproduced from Godwin-Austen (1920), pl. CLXV, fig. 4.

Specimens were collected in eastern Nepal, at less than 30–40 km west of the type locality, Darjeeling, and at a similar altitude (7000 ft = 2100 m). Based on shell size Godwin-Austen (1920) distinguished var. major (SH 13.0, SW 5.2) and var. minor (SH 8.0–9.0, SW 3.75–4.0). He figured the genitalia of var. major from Damsang, Sikkim, with its hand-shaped flagellum (Fig. 3B) containing four finger-like processes, of which the first is short, while the second and the third are fused to a single finger. In contrast, the flagellum of Nepalese specimens has five distinct finger-like processes. Based on the shell size, Nepalese specimens belong to the var. minor. For the time being the taxonomic status of both varieties remains unclear.

CDZMTU056/1 juvenile shell and CDZMTU056P/1 specimen (dissected), Godawari, approx. 150 m above the Godawari National Herbarium, Lalitpur, Central Nepal, 1636 m, 27.5965N, 85.3894E, 02.XII.2006, leg. P.B. Budha.

"Munipur" NE India.

Burrail range, Augaoluo Peak, Naga Hills, NE India; Nepal.

Measurements (n = 1): SH 13.3 mm, SW 6.2 mm, HA 5.3 mm, WA 3.8 mm, Wh 7.0, approx. 2× higher than wide, solid, ovate-conic, yellowish. Surface, glossy, with widely spaced incised radial striations. The incised striations start from the first whorl, sides convex, suture shallow. Aperture semi-oval, 1.4× higher than wide, peristome simple and thick, columellar margin short and truncate.

(n = 1) (Fig. 4). Vas deferens widens towards the spermoviduct and opens into the terminal part of the small, pear shaped epiphallus. Flagellum comb-like with numerous notches in the comb, the terminal notch comparatively wider. The basal end of the penis cylindrical, widening from the middle to the proximal end (Fig. 4). Vagina very short, nearly 1/5^th of the length of the penis. The penial retractor muscle close to the flagellum. The gametolytic sac is elongated, connected to the gametolytic duct by a narrow neck. The convoluted mass of the hermaphroditic duct is thick and compact and the albumen gland in the dissected samples is short.

Figure 4. 

Genitalia of Glessula cf. hebetata: CDZMTU056P, Godawari, Lalitpur, Central Nepal.

The sculpture, thick peristome and size of the Nepalese specimen match with the original description of G. hebetata Godwin-Austen, 1920 (p. 49, pl. 162, fig. 26). The genitalia suggest that G. cf. hebetata is closely related to G. ochracea Godwin-Austen, 1918, and G. orophila (Reeve, 1849), all sharing a similar comb-shaped flagellum. Yet, the shell of G. ochracea is larger (SH 21.25, SW 9.25) and shows a sharper striation (Godwin-Austen 1920). In contrast, with respect to G. orophila, Godwin-Austen (1920, p. 4) questioned the identity of the genitalia figured under this name by Semper (1873, pl. 12, fig.14–16). Hence, there is no other comparative data available with respect the genital anatomy of G. cf. hebetata, including of G. hebetata itself. However, the shell of the single specimen of putative G. hebetata from Nepal looks similar to the figure of Godwin-Austen (1920, p.49, pl. CLXII, fig. 26) which is why this specimen is referred to as G. cf. hebetata.

Holotype: CDZMTU057P/1, Suridobhan, left bank of Tamakoshi River, Dolakha District, Central Nepal, North face, rocky hill slope, mixed Schima wallichi forest with dominant Lauraceae trees,1023 m, 27.754754N, 86.216755E, 03.II.2009, leg. P.B. Budha. Paratypes: CDZMTU058/13 shells and CDZMTU058P/2 specimens (dissected) from the type locality (same data as holotype).

Only known from the type locality.

The species name refers to the type locality Tamakoshi River valley.

Measurements (n = 4): SH 17.7–19.5 mm, SW 9.2–9.6 mm, HA 8.6–8.8 mm, WA 4.9–5.0 mm, Wh 7.0–8.0; holotype: SH 19.5 mm, SW 9.6 mm, HA 8.8 mm, WA 4.9 mm, Wh 7.8. The largest shell measured 19.5 mm, approx. 2× higher than wide, solid, ovate-conic, light yellowish. Surface glossy, with widely spaced incised radial striations, stronger towards the suture and faint at the middle to lower part of the whorls. The first whorl smooth, blunt with fine and dense striations near the suture. Sides convex, suture fairly impressed. Aperture nearly ovate, 1.7× higher than wide, peristome simple and thick, columellar margin abruptly truncate, columella slightly curved.

(Fig. 13A). Teeth pointed, lateral cusps not distinct. Central tooth smaller and with a narrower base than the lateral teeth.

(n = 3) (Fig. 5). Vas deferens with a constant diameter. Flagellum wide comb-like with numerous notches ending in a short hook at the free end. Vagina very short nearly 1/6^th length of the penis. Gametolytic sac is oval, connected to the gametolytic duct by a short neck. The penial retractor muscle close to the flagellum. The mass of the hermaphroditic duct highly developed in all dissected samples. Interior of penis with two bulky masses of ‘brain-like folds’ (Fig. 5B).

Figure 5. 

Genitalia of G. tamakoshi sp. n., holotype: CDZMTU057P, A General view B Interior of penis of the same, Suridobhan, left bank of Tamakoshi River, Dolakha District, Central Nepal.

Conchologically, G. tamakoshi sp. n. is similar to South Indian G. indica Gude, 1914 (genitalia unknown) and Sri Lankan G. serena (Benson, 1860). Yet, G. indica has a much wider shell and relatively more whorls (>9 whorls), while the penis of G. serena contains one longitudinal fold and two folds proximal to this longitudinal fold. Schileyko (1999, p. 542, fig. 711) referred the longitudinal fold to as pilaster and the two proximal folds to as the spiral stimulators. In G. tamakoshi sp. n. the interior of the penis contains a bulky masses of brain-like folds (Fig. 5B).

India, Sri Lanka, Bangladesh, Myanmar, Nepal (Godwin-Austen 1920, Schileyko 1999, Raheem et al. 2014, Budha et al. 2015).

Rishetia longispira Godwin-Austen, 1920.

Shell slender, elongately turreted, generally more than 2.5× higher than wide, columella truncated, transluscent, shell sculpture in general stronger than in Glessula. Vagina generally longer than penis. The proximal part of the male reproductive organs with a simple flagellum, either like a knob or tubular sac, epiphallic caecum generally present.

CDZMTU059/24 shells and CDZMTU059P/5 specimens, Chitwan National Park, Central Nepal, riverine forest, opposite bank of Rapti River at Sauraha, 142–211 m, 27.571774N, 84.489514E, 8.XI.2008. CDZMTU060/6 shells, Kumrose Community Forest, 197 m, 27.556519N, 84.553028E, 21.X.2008. CDZMTU061/1 shell, Baghmara Community Forest, 201 m, 27.57750N, 84.466017E, 20.X.2008, leg. P.B. Budha. R. hastula (Benson, 1860) at NHMUK, Godwin-Austen colln. Reg. No. 3557.03.VII.1.

West Bengal “Pankabari (= Pankhabari), prope Darjeeling”, India.

NE India, Nepal (Budha et al. 2015).

Measurements (n = 8): SH 9.5–13.6 mm, SW 3.5–4.1 mm, HA 3.3–3.6 mm, WA 2.0–2.5 mm, Wh 8.0–10.0; approx. 3× higher than wide, slender, elongate, brownish, with dense radial riblets all over the shell. The first whorl blunt and smooth, fine riblets starting from the second whorl. Suture deep, spire rounded. Aperture ovate elliptical, nearly 2× higher than wide, peristome thin, columellar margin calloused whitish, obliquely truncate at the base.

(n = 5) (Fig. 6). Flagellum very short tubular sac; there is a very short knob-like epiphallic caecum. Penis cylindrical, basal end comparatively narrow, swollen at the middle and proximal portions cylindrical. Epiphallus basally swollen and the proximal portion tapering. The penial retractor muscle far apart from the flagellum. Gametolytic sac balloon-like, separated from the gametolytic duct by a narrow neck. A mature dissected specimen contained 4–5 gelatinous eggs in the spermoviduct. Another mature specimen contained a spermatophore in the gametolytic sac. This is the first observation of a glessuline spermatophore (Fig. 6B). Vagina short, nearly half the length of the penis. Albumen gland elongate and yellowish; hermaphroditic duct thinner than the albumen gland in the observed specimens.

Figure 6. 

Genitalia of Rishetia hastula, CDZMTU059P, A General view B Spermatophore of the same, Chitwan National Park, riverine forest opposite bank of Sauraha, Rapti River.

R. hastula is common in subtropical riverine floodplain forest leaf litter at lower altitudes (up to 300 m) in Chitwan National Park and the adjacent bufferzone community forests.

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.

Nepal.

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

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.

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

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

(n = 5) (Fig. 7A–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.

Figure 7. 

Genitalia of R. kathmandica sp. n. and Glessula (Rishetia) longispira Godwin-Austen, 1920. A Interior of penis of R. kathmandica sp. n., holotype CDZMTU062P B General view of the same, Godawari Botanical Garden, Lalitpur, Central Nepal C General view of G. (R.) longispira reproduced from Godwin-Austen (1920), pl. CLXV, fig. 4.

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.

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.

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.

(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.

Figure 8. 

Genitalia of R. cf. mastersi and Rishetia sp.: A General view of R. cf. mastersi, CDZMTU065P B Interior of penis of the same, Kurintar, Chitwan, degraded riverine bushes with big boulders, mixed Shorea robusta forest C General view of Rishetia sp. CDZMTU078P D Interior of penis of the same, Boshikharka, Dhading, Central Nepal.

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).

Holotype: CDZMTU067P/1, Nagarjun Forest, Balaju-Jamacho trail, Nagarjun-Shivapuri National Park, Kathmandu, Nepal, 1850 m, 27.745997N, 85.287240E, 24.I.2009, leg. P.B. Budha, R. Devkota, S. Khatiwara and S. Khanal. Paratypes: CDZMTU067/9 shells and CDZMTU068P/1 specimen from the type locality (same data as holotype). Paratypes: CDZMTU069P/1 specimen (dissected), Phulchowki Hill, mixed Rhododendron forest, 2324 m, 27.578317N, 85.396885E, 03.V.2007, leg. P.B. Budha.

Nagarjun-Shivapuri National Park and Phulchowki Hill, Central Nepal.

The name is derived from the type locality Nagarjun Forest.

Measurements (n = 4): SH 33.2–38.4 mm, SW 10.6–11.9 mm, HA 10.2–10.8 mm, WA 5.5–6.2 mm, Wh 10–11.0; holotype: SH 38.0 mm, SW 12.0 mm, HA 10.5 mm, WA 6.3 mm, Wh 11; approx. 3.3× higher than wide, elongately turreted, thick, reddish-brown or dark chestnut colour. Surface striated with obliquely raised riblets on the first 2–3 whorls, later whorls with comparatively thin and dense sculpture. The first whorl smooth, rounded. Sides rather flat, suture shallow. Aperture ovate, 1.8× longer than wide, peristome thin, inner side of the aperture thickened and whitish, columella slightly truncate at the base.

(Fig. 13E). Central tooth very small, lacks cusps, lateral teeth shouldered.

(n = 2) (Fig. 9). All specimens have a long vas deferens. Flagellum and epiphallic caecum are reduced to two very short knobs (Fig. 9A). Penis cylindrical, with a nearly constant diameter in its proximal half, distally it rapidly expands into a bulbous section before the diameter contracts to somewhat less than the proximal penis, narrowing slightly distally. The penial retractor muscle far apart from the flagellum. The inner surface contains weakly convoluted folds (Fig. 9B). Epiphallus length about 1/3 of penis length. Vagina nearly as long as the penis. Gametolytic duct cylindrical, ends into a simple gametolytic sac. Hermaphroditic duct is loosely convoluted and connected at the middle of the albumen gland.

Figure 9. 

Genitalia of R. nagarjunensis sp. n., holotype: CDZMTU067P, A General view B Interior of penis of the same, Nagarjun forest, Balaju-Jamacho trail Nagarjun-Shivapuri National Park, Kathmandu, Nepal.

The shell of R. nagarjunensis sp. n. is similar in size and shape to that of sympatric R. kathmandica sp. n. However, the shell of R. kathmandica sp. n. is more slender and has more whorls than R. nagarjunensis sp. n. Conversely, R. nagarjunensis sp. n. has a wider body whorl, a comparatively more robust shell, and stronger radial ribs than R. kathmandica sp. n. The genitalia of both species are consistently different due to the reduced knob-like flagellum and epiphalic caecum in R. nagarjunensis sp. n., as well as by the inner surface of the penis, which in R. nagarjunensis sp. n. shows three loosely convoluted folds, whereas in R. kathmandica sp. n. it shows distinct rectangular zigzag folds (Fig. 7A1).

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).

Only reported from the type locality.

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

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.

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

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

(n = 2) (Figs 10A–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).

Figure 10. 

Genitalia of R. rishikeshi sp. n., holotype: CDZMTU0170P, A General view B Interior of penis of the same, Jhawalepakho Community Forest, Ridi, Gulmi District, montane hill Shorea robusta forest.

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.

Holotype: CDZMTU072P/1 specimen (dissected), Godawari, along the Godawari-Phulchowki road, approx. 200 m above the Naudhara Temple, 1837 m, 27.5766N, 85.3786E, 02.X.2008, leg. P.B. Budha. Paratype: CDZMTU072/1 shell (same locality). Paratypes: CDZMTU073/3 shells, Phulchowki Hill, Central Nepal, mixed forest, 2324 m, 27.578317N, 85.396885E, 04.V.2007, leg. P.B. Budha and R. Devkota.

Only known from the type locality.

The name refers to the typical subuline-like shell shape.

Measurements (n = 3): SH 10.8–14.9 mm, SW 3.6–4.1 mm, HA 3.3–3.5 mm, WA 1.8–1.9 mm, Wh 9.0–9.5; holotype: SH 10.8 mm, SW 3.6 mm, HA 3.3 mm, WA 1.8 mm, Wh 9.0; approx. 3.1× higher than wide, elongated, thin, dull brown. Surface shining obliquely striated, covered with thin transparent epidermis, slightly denser on the 3^rd and 4^th whorl; transverse sculpture more widely separated on the penultimate and body whorls. Whorls shouldered. The first whorl blunt and smooth, eroded. Sides rounded; suture deep. Aperture ovate elliptical, approx. 2× higher than wide, peristome thin, columellar margin calloused whitish, slightly truncate at the base.

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

Dark grey and papillate.

(n = 1) (Fig. 11). Vas deferens very long, enters into the epiphallus at some distance from the base of the flagellum. The flagellum is long and C-shaped. Epiphallic caecum very short. Epiphallus approx. as long as the penis. The basal part of the penis is comparatively wider than the proximal part. The penial retractor muscle far apart from the flagellum. Gametolytic sac elongated. The vagina is nearly as long as the penis. Albumen gland elongated and hermaphrodite duct is connected at the middle of the gland.

Figure 11. 

Genitalia of R. subulata sp. n., holotype: CDZMTU072P, Godawari, along the Godawari-Phulchowki road approx. 200 m above the Naudhara Temple.

R. subulata sp. n. is similar to R. hastula (Benson, 1860) and R. tribhuvana sp. n., but R. subulata sp. n. has a wider body whorl and more blunt first whorl than R. hastula, while its 2^nd and 3^rd whorls have equal diameters (unequal diameters in R. hastula) (Fig. 2 D1 and J1). The body whorl in R. subulata sp. n. is much wider than in R. tribhuvana sp. n. (Fig. 2 J and K). Moreover, the flagellum of R. subulata sp. n. much larger than the epiphallic caecum, whereas in R. tribhuvana sp. n. the flagellum and epiphallic caecum are of similar sizes. In R. hastula the flagellum and the epiphallic caecum are very small.

Holotype: CDZMTU074P/1 specimen, Tribhuvan University garden, Kirtipur, Kathmandu, Nepal, 1320 m, 27.680203N, 85.289154E, 15.VIII.2006, leg. P.B. Budha. Paratypes: CDZMTU074/15 shells and CDZMTU075P/5 specimens (3 dissected) from the type locality, 22.III.2011, leg. P.B. Budha. Paratypes: CDZMTU076/6 shells, Champadevi Forest, Kirtipur, Kathmandu, Nepal, 1680 m, 27.653060N, 85.244785E, 23.VIII.2006, leg. P.B. Budha. Paratypes: CDZMTU077/4 shells, Nagarjun Forest, 1582 m and 1680 m, 27.742616N, 85.293248E, 07.I.2009, 16.I.2009, leg. S. Khanal and S. Khatiwara.

Hill forests of Kathmandu valley, Nepal.

The name refers to the type locality, Tribhuvan University garden

Measurements (n = 12): SH 7.5–11.0 mm, SW 2.7–3.0 mm, HA 2.5–3.0 mm, WA 1.4–2.0 mm, Wh 8.5–9.5; holotype: SH 10.1 mm, SW 3.0 mm, HA 2.5 mm, WA 2.0 mm, Wh 9; approx. 3.3× higher than wide, slender, thin, dull brown. Surface striated with radial fine ribs, much denser on the 3^rd and 4^th whorls; ribs widely separated on the penultimate and body whorls. The first whorl blunt and smooth. Spire rounded; suture deep. Aperture ovate elliptical; approx. 2× higher than wide, peristome thin; columellar margin calloused whitish, obliquely truncate at the base.

(n = 4) (Fig. 12). Vas deferens long. Flagellum slightly shorter than the epiphallic caecum. The length of the flagellum nearly two-thirds of that of the epiphallus. The basal part of the penis narrower than the proximal part. The vagina nearly as long as the penis. The penial retractor muscle far apart from the flagellum. The gametolytic sac is rounded and distinct from the gametolytic duct. The hermaphrodite duct is connected at the base of the albumen gland.

Figure 12. 

Genitalia of R. tribhuvana sp. n., holotype: CDZMTU077P, Tribhuvan University garden, Kirtipur, Kathmandu, Nepal.

R. tribhuvana sp. n. is the smallest Rishetia species in Nepal. Conchologically, it is “intermediate” between R. hastula (Benson, 1860) and R. roberti Godwin-Austen, 1920. R. tribhuvana sp. n. differs from both these species by its weaker radial sculpture compared to R. hastula and its narrower body whorl compared to R. roberti. Moreover, the illustrations of Godwin-Austen (1920, pl. CLXIII, fig. 10) suggest that R. roberti has a rounded first whorl, whereas it is nearly flat in R. tribhuvana sp. n. The flagellum and epiphallic caecum are well-developed and nearly equal in size in R. tribhuvana sp. n., whereas in R. hastula the flagellum is very small and the epiphallic caecum is only a minute-knob. R. tribhuvana sp. n. and R. hastula are known from geographically different locations. The former is a hill species reported above 1300 m, while the latter is known only from the plain below 300 m elevation. R. roberti is also a hill species from Richila peak, Sikkim. The presence of R. tribhuvana sp. n. in the garden of Tribhuvan University is due to a historical connection between this garden and the Champadevi hill Forest, about 4 km south 300–400 m higher from the university premises. This connection has been lost because of human settlement.

Figure 13. 

Radula of Glessula and Rishetia. A G. tamakoshi sp. n., CDZMTU057P, Suridobhan, Dolakha B R. kathmandica sp. n., CDZMTU062P, Godawari, Lalitpur C R. rishikeshi sp. n., CDZMTUO70P, Jhawalepakho, Ridi, Gulmi D R. subulata sp. n., CDZMTU072P, Godawari, Lalitpur E R. nagarjunensis sp. n., CDZMTU067P, Raniban, Balaju, Kathmandu.

Figure 14. 

Shells and animals of glessulines. A Achatina tenuispira, possible syntype from ‘Teria Ghat’ labelled as Subulina tenuispira Bens. ZMCU l.102045, Cambridge B Rishetia longispira Godwin-Austen, 1920, 33 syntypes, Rishetchu, Sikkim, NHMUK, Reg. No. 1903.7.1.552 C Rishetia tenuispira, W. Khasi Hills NHMUK, London, Acc. No. 1582.03.VII.I D Two shells of Rishetia kathmandica sp. n. from Nepal, previously determined by Schileyko (1999) as Rishetia tenuispira (Benson, 1836) (two lots : Central Nepal, Kathmandu valley, 1.3 km NW from Balaju, Rani-Ban Range, Nagarjun Royal Forest, 1480 m a.s.l., leg./det. A.G. Kuznetsov, 28.04.1995. ZMMU, No. Lc-34221 and 1600–1800 m a.s.l., leg./det. A.G. Kuznetsov, 28+30.04.1996. ZMMU, No. Lc-34222 E Rishetia kathmandica sp. n. Godawari, Lalitpur F Rishetia mastersi, Kurintar, Nepal.