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Research Article
Conchological differentiation and genital anatomy of Nepalese Glessulinae (Gastropoda, Stylommatophora, Subulinidae), with descriptions of six new species
expand article infoPrem B. Budha§, Fred Naggs|, Thierry Backeljau
‡ University of Antwerp, Antwerp, Belgium
§ Tribhuvan University, Kathmandu, Nepal
| Natural History Museum, London, United Kingdom
¶ Royal Belgian Institute of Natural Sciences, Brussels, Belgium
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Abstract

Eleven species of Glessulinae belonging to the genera Glessula Martens, 1860 (three species) and Rishetia Godwin-Austen, 1920 (eight species) are reported from Nepal, six of which are new to science and are described here, viz., G. tamakoshi Budha & Backeljau, sp. n., R. kathmandica Budha & Backeljau, sp. n., R. nagarjunensis Budha & Naggs, sp. n., R. rishikeshi Budha & Naggs, sp. n., R. subulata Budha & Naggs and R. tribhuvana Budha, sp. n. and two are new records for Nepal viz. G. cf. hebetata and R. cf. mastersi. The relation between the shell height-width ratio and the structure of the proximal part of the male reproductive organs in Glessulinae is explored. Illustrations and a key for the identification of the Nepalese Glessulinae are provided, including the first record of a spermatophore in Rishetia.

Keywords

flagellum, genitalia, Glessula, identification key, Nepal, Rishetia, shell sculpture, spermatophore

Introduction

The Glessulinae Godwin-Austen, 1920 are one of the most speciose achatinoid subfamilies (Gastropoda, Stylommatophora) with more than 160 nominal species. The majority of these are known from India and Sri Lanka (Nevill 1878, Beddome 1906, Pilsbry 1908-1909, Gude 1914, Godwin-Austen 1920). A few species occur in Myanmar and very few are recorded from Thailand, Vietnam, Borneo, Sumatra, and Java (Tenison-Woods 1888, Pilsbry 1908–1909, Panha 1995–1996, Schileyko 2011). Kashmir and Himachal Pradesh, India, form the western limit of glessulines in the Himalaya, where they are represented by only three species: Glessula huegeli (L. Pfeiffer, 1842), G. paupercula (Blanford, 1861) and G. tornensis Blanford, 1870 (Gude 1914, Surya Rao and Mitra 2005). In contrast, the eastern Himalaya, the NE Indian states of West Bengal, Sikkim, Assam, Arunachal Pradesh, Nagaland, Meghalaya, Mizoram and Manipur, including Nepal (east of Kaligandaki river) shows a much higher (n > 50) glessuline species diversity (Godwin-Austen 1920, Budha et al. 2015).

In what is widely consulted as the most recent review of gastropod classification, Bouchet and Rocroi (2005) accept the placement of Rishetia Godwin-Austen, 1920 as the type genus of the Rishetiinae Schileyko, 1999 within Subulinidae but do not follow Schileyko, 1999 in placing Glessula Martens, 1860 in a separate family, the Glessulidae Godwin-Austen, 1920. They place the Glessulinae within the Subulinidae. However, the generic status and relationship between Glessula and Rishetia remain unclear and Rishetia is often synonymised with Glessula (Zilch 1959, Mitra et al. 2005, Ramakrishna et al. 2010). Until this wide range of doubt is resolved, from synonymising Rishetia within Glessula to placing Rishetia in a distinct family, we provisionally follow Godwin-Austen (1920) in recognising Rishetia and Glessula as being closely related groups at generic level. This uncertainty can be largely attributed to the limited anatomical information on glessulids, the taxonomy of which is largely based on shells, and to the wide geographical range of species that have been included within Glessula. Outside of South Asia Glessula is known from shell characters only. Conversely, glessuline genital anatomy exhibits significant variation, but the genitalia of only a few species of this large group are currently documented (Semper 1877, Godwin-Austen 1918, 1920, Fernando 1950, Schileyko 1999). More generally, since Godwin-Austen’s (1920) work, only a few sporadic studies of glessulines have been published (Schileyko and Kuznetsov 1996, Schileyko 1999, Ramakrishna and Mitra 2002, Mitra et al. 2005, Surya Rao and Mitra 2005, Surya Rao et al. 2007, Raheem et al. 2008, 2014, Ramakrishna et al. 2010 and Budha et al. 2015).

To date, only four nominal glessuline species have been reported from Nepal, namely Glessula subjerdoni Beddome, 1906, Glessula orobia (Benson, 1860), Rishetia tenuispira (Benson, 1836) and Rishetia hastula (Benson, 1860) (Schileyko and Kuznetsov 1996, Schileyko 1999, Budha et al. 2015). In the present study we include data on the genital anatomy of 10 species, describe six new species and provide a dichotomous identification key to all currently known Glessula and Rishetia species in Nepal.

Material and methods

From 2006 to 2010 glessuline shells and specimens were hand-collected during surveys in the Baitadi, Bardiya, Dadeldhura, Darchula, Chitwan, Dolakha, Gulmi, Ilam, Kailali, Kathmandu, Lalitpur, Nawalparasi and Tanahun districts in Nepal, including three national parks: Shivapuri-Nagarjun National Park, Langtang National Park and Chitwan National Park. Collecting locations are shown in Figure 1.

Figure 1. 

Collecting locations for glessulines in Nepal.

Snails were drowned in water and preserved in 90% ethanol, which was changed at least once within a week after collection. All new material is deposited in the Central Department Zoology Museum of Tribhuvan University (CDZMTU), Nepal. The numbers of shells in the samples are indicated after the registration numbers. The letter ‘P’ indicates that the sample consists of live-collected specimens preserved in ethanol. Illustrations were made using a camera lucida mounted on a stereomicroscope. Features of the interior of the penis were drawn from photographs by Rajman Maharjan (Natural History Museum, Kathmandu). Whorls were counted and shells were measured (in mm) with electronic digital callipers as described by Kerney and Cameron (1979). All descriptions in this paper are based on material collected in Nepal.

We avoided the shell terms ‘protoconch’ and ‘teleoconch’ because the demarcation between these shell parts is unclear in glessulines. So we used the first whorl and second whorl for ‘protoconch’and the other whorls for ‘teleoconch’. The term ‘apical whorls’ is used for the first three or more whorls together. The terminology of the reproductive organs was modified from Tompa (1984). We arbitrarily differentiate the proximal parts of the male reproductive organs as ‘epiphallic caecum’, being the structure positioned close to where the vas deferens joins the epiphallus, and as ‘flagellum’, being the other sac-like structure connected to the epiphallus. The internal surface of the penis is referred to as smooth or folded to avoid ill-defined functional terms such as ‘stimulator’ and ‘pilaster’. In this paper we refer proximal part toward the free end of the male genitalia and the distal part closer toward genital orifice.

Type and other reference material was examined in the collections at the Natural History Museum, London (NHM), the University Museum of Zoology, Cambridge (UMZC), the Royal Belgian Institute of Natural Sciences, Brussels (RBINS) and the Zoological Museum of Moscow State University (ZMMU), Moscow, Russia.

Abbreviations used

Genitalia: AG: Albumen gland. AT: Atrium. EC: Epiphallic caecum. EP: Epiphallus. F: Flagellum. GD: Gametolytic duct. GS: Gametolytic sac. HD: Hermaphrodite duct. IP: Interior of Penis. P: Penis. PR: Penial retractor muscle. SO: Spermoviduct. V: Vagina. VD: Vas deferens.

Shell measurements: HA: height of aperture. SH: shell height. SW: shell width. Wh: number of whorls. WA: width of aperture.

Systematics

Subulinidae P. Fischer & Crosse, 1877

Glessulinae Godwin-Austen, 1920

Glessula von Martens, 1860

Distribution

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

Type species

Achatina ceylanica L. Pfeiffer, 1845

Main characteristics

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 35).

Glessula orobia (Benson, 1860)

Figs 2A, 3

Achatina orobia B. : Benson 1860, p. 461.

Achatina orobia, Benson: Hanley and Theobald 1876, pl. 18, fig. 7.

Stenogyra (Glessula) orobia, Benson: Nevill 1878, p. 170.

Glessula orobia (Benson): Pilsbry 1909, p. 96.

Glessula orobia Benson: Gude 1914, p. 427.

Glessula orobia Bs.: Godwin-Austen 1920, p. 19.

Material examined

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.

Type locality

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

Distribution

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 B Glessula 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 F R. 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.

Genitalia

(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 1/4th 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.

Remarks

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.

Glessula cf. hebetata Godwin-Austen, 1920

Figs 2B, 4

Glessula hebetata: Godwin-Austen 1920, p. 49, pl. 162, fig. 26.

Material examined

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.

Type locality

"Munipur" NE India.

Distribution

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

Shell

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.

Genitalia

(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 1/5th 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.

Remarks

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.

Glessula tamakoshi Budha & Backeljau, sp. n.

Figs 2C, 5, 13A

Material examined

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).

Distribution

Only known from the type locality.

Etymology

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

Shell

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.

Radula

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

Genitalia

(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 1/6th 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.

Remarks

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).

Rishetia Godwin-Austen, 1920

Ranibania Schileyko and Kuznetsov, 1996, Ruthenica 5: 158–160 (type species: Achatina tenuispira Benson, 1836).

Distribution

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

Types species

Rishetia longispira Godwin-Austen, 1920.

Main characteristics

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.

Rishetia hastula (Benson, 1860)

Figs 2D, 6

Achatina hastula B.: Benson 1860, p. 461.

Achatina (Electra) hastula Benson: Hanley and Theobald 1876, pl. 18, fig. 4.

Stenogyra (Glessula) hastula, Benson: Nevill 1878, p. 169.

G. lessula hastula (Benson): Pilsbry 1909, p. 93.

Glessula hastula Benson: Gude 1914, p. 414.

Glessula (Rishetia) hastula Benson: Godwin-Austen 1920, p.16.

Material examined

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.

Type locality

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

Distribution

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

Shell

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.

Genitalia

(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.

Remarks

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.

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. 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.

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.

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.

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.

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).

Rishetia nagarjunensis Budha & Naggs, sp. n.

Figs 2G, 9, 13E

Material examined

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.

Distribution

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

Etymology

The name is derived from the type locality Nagarjun Forest.

Shell

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.

Radula

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

Genitalia

(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.

Remarks

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).

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 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.

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.

Rishetia subulata Budha & Naggs, sp. n.

Figs 2J, 11

Material examined

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.

Distribution

Only known from the type locality.

Etymology

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

Shell

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 3rd and 4th 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.

Radula

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

Animal

Dark grey and papillate.

Genitalia

(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.

Remarks

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 2nd and 3rd 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.

Rishetia tribhuvana Budha, sp. n.

Figs 2K, 12

Material examined

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.

Distribution

Hill forests of Kathmandu valley, Nepal.

Etymology

The name refers to the type locality, Tribhuvan University garden

Shell

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 3rd and 4th 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.

Genitalia

(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.

Remarks

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.

Key to the Nepalese Glessulinae

1 Shell ovate-conic, adult shell height/width ratio < 2.5 2 (Glessula)
Shell elongately turreted, adult shell height/width ratio > 2.5 4 (Rishetia)
2(1) First two whorls with spiral lirae (Fig. 2A1), flagellum hand-shaped (Fig. 3) G. orobia
First two whorls without spiral lirae, flagellum comb-shaped (Figs 45) 3
3(2) Adult shell height < 15 mm, flagellum comb-shaped, vas deferens becomes wider towards spermoviduct (Fig. 4) G. hebetata
Adult shell height > 15 mm, flagellum comb-shaped, diameter of vas deferens constant (Fig. 5) G. tamakoshi sp. n.
4(1) Adult shell height < 20 mm 5
Adult shell height > 20 mm 9
5(1) Adult shell height/width ratio ≤ 3 6
Adult shell height/width ratio > 3 8
6(5) Flagellum long 7
Flagellum very short, epiphallic caecum very short-knob (Fig. 6) R. hastula
7(5) Epiphallic caecum longer than flagellum (Fig. 8) R. mastersi
Epiphallic caecum nearly as long as flagellum (Fig. 10) R. rishikeshi sp. n.
8(5) Epiphallic caecum much shorter than flagellum (Fig. 11) R. subulata sp. n.
Epiphallic caecum nearly as long as flagellum (Fig. 12) R. tribhuvana sp. n.
9(4) Shell slender, 10–14 whorls, flagellum and epiphallic caecum simple sacs (Fig. 7) R. kathmandica sp. n.
Shell slender, 10–11 whorls, flagellum and epiphallic caecum simple knob (Fig. 9) R. nagarjunensis sp. n.

Discussion

Godwin-Austen (1920) differentiated Rishetia from Glessula sensu stricto on the basis of the male reproductive organs of four Glessula species G. ochracea, G. orobia var. major, G. orophila and G. inornata, and two species of Rishetia, R. longispira (type species) and R. garoense Godwin-Austen, 1920. He reported that Glessula has a comb-like flagellum and Rishetia has a simple sac-like flagellum. Probably based on the elongated shell of R. longispira he assigned several other slender and elongated Himalayan species to Rishetia. Therefore we explored the relation between shell form and genitalia in 10 species of Glessula and 10 species of Rishetia (Table 1). This suggests that the male reproductive organ of Glessula and Rishetia differs by: (1) the shape of the flagellum, being hand- or comb-shaped without an epiphallic caecum in Glessula (Figs 35) vs. a simple knob or tubular sac with an epiphallic caecum in Rishetia (Figs 612), (2) the penial retractor inserting close to the flagellum and epiphallus in Glessula vs. penial retractor inserting far from the flagellum near the penis/epiphallus junction in Rishetia, and (3) the very short epiphallus in Glessula vs. the comparatively longer epiphallus in Rishetia. Recent data on the genitalia of G. ceylanica (the type species of Glessula) shows that this species has a very distinct hand-like flagellum with a small thumb and five fingers (D. Raheem, pers communication). Taken altogether, it appears as if these genital characters are correlated with the shell height/width ratio, such that the shell height/width ratio in Glessula is < 2.5, while in Rishetia it is always > 2.5, at least in the species listed in Table 1. Also the shell sculpture tends to differ between Glessula and Rishetia, with Glessula usually having a somewhat weaker sculpture than Rishetia. The extent to which this putative differentiation between Glessula and Rishetia can be maintained when data on more species from a wider geographic range become available remains to be established.

Qualitative correlation between shell height/width ratio and proximal part of the male genital parts in Glessula and Rishetia (n refers to the number of shells measured).

Species SH SW SH/SW ratio Flagellum, epiphallic caecum (EC) Reference
Glessula ceylanica (n=2) 23.0 11.0 2.1 Hand-shaped, EC absent 4, 1
G. cf. hebetata (n=1) 13.3 6.2 2.1 Comb-shaped, EC absent 1
G. inornata (n=3) 27.0 12.0 2.2 Comb-shaped, EC absent 2, 7
G. oakesi (n=2) 13.8 6.0 2.3 Hand-shaped, EC absent 2
G. ochracea (n=1) 21.3 9.3 2.3 Comb-shaped, EC absent 2,3
G. orobia (n=6) 7.7 4.3 1.8 Hand-shaped, EC absent 1
G. orobia var. major (n=2) 11.8 5.8 2.0 Hand-shaped, EC absent 2
G. orophila (n=4) 19.2 9.6 2.0 Comb-shaped, EC absent 2
G. serena (n=3) 21.0 9.5 2.2 Comb-shaped, EC absent 3, 6
G. tamakosi (n=4) 18.6 9.3 2.0 Comb-shaped, EC absent 1
Rishetia capillacea (n=2) 10.5 3.5 3.0 Tubular sac, EC ? 1
R. garoense (n=2) 27.0 5.3 5.2 Tubular sac, EC ? 2
R. hastula (n=10) 11.5 3.8 3.0 Tubular sac, EC present 1
R. kathmandica (n=22) 33.3 8.6 3.9 Tubular sac, EC present 1
R. longispira (n=4) 39.7 9.3 4.3 Tubular sac, EC present 2
R. cf. mastersi (n=13) 14.7 5.5 2.7 Tubular sac, EC present 1
R. nagarjunensis (n=4) 36.5 11.1 3.3 Simple knob, EC present 1
R. rishikeshi (n=7) 13.2 5.0 2.7 Tubular sac, EC present 1
R. subulata (n=4) 11.9 3.8 3.1 Tubular sac, EC present 1
R. tribhuvana (n=7) 9.6 2.9 3.3 Tubular sac, EC present 1

Finally, Schileyko (1999) recognised the Glessulidae Godwin-Austen, 1920 as a distinct family and introduced the Rishetiinae (with Rishetia as type genus) as a new subfamily within the Subulinidae. He also included the genera Eutomopeas Pilsbry, 1946, Tortaxis Pilsbry, 1906 and Bacillum Theobald, 1870 within Rishetiinae based on the presence of some form of truncation of the columella. It remains to be decided whether this classification (and separation) of Glessula and Rishetia will stand a phylogenetic analysis. This study illustrated the spermatophore of R. hastula, the first observation of a spermatophore in Glessulinae. This observation adds to the accumulating evidence that in contrast to Tompa’s (1984) suggestion that Achatinidae and their relatives do not produce spermatophores, these structures may be not uncommon in the Achatinoid clade of the Stylommatophora. Indeed, spermatophores have been reported in Achatinidae (Plummer 1975), Subulinidae (Baker 1945, Marcus 1968, Naggs 1994, Medeiros et al. 2013) and Streptaxidae (de Winter et al. 1999, Gerlach and van Bruggen 1999, de Winter and Vastenhout 2013, Rowson and Tattersfield 2013).

Acknowledgements

We gratefully acknowledge funding from the Royal Belgian Institute of Natural Sciences (RBINS), Brussels, and the Darwin Initiative, Defra, UK through the NHM project ‘Developing land snail expertise in South and South East Asia’ to P.B. Budha. We are indebted to the director of the Department of National Parks and Wildlife Conservation, Babarmahal, Kathmandu and the wardens of the Chitwan National Park, Langtang National Park and Shivapuri National Park for the permission to collect specimens. We thank R. Devkota, S. Khatiwara and S. Khanal for their field assistance to P.B. Budha, Jonathan Ablett (NHMUK) for providing access of material at NHM, Julien Cillis (RBINS) for SEM images, and Yves Barette (RBINS) for stacking photographs. We are grateful to Dinarzarde Raheem (RBINS and NHM) for providing access to dissected material of Glessula capillacea and other figures of Glessula and to Alexander Sysoev (ZMMU), Moscow for providing images of Rishetia tenuispira collected from Nepal. We are grateful to Ben Rowson, National Museum of Wales and Edmund Gittenberger, Leiden, the Netherlands for their valuable comments.

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