Re-description of the type species of the genera Ganesella Blanford, 1863 and Globotrochus Haas, 1935; with description of a new Ganesella species from Thailand (Eupulmonata, Camaenidae)

Abstract The taxonomy of the speciose genus Ganesella W.T. Blanford, 1863 and the endemic genus Globotrochus Haas, 1935 is unclear since the anatomical characters of the the type species of these two genera have never been reported before. Therefore, the present paper provides the first anatomical descriptions of the reproductive apparatus, pallial system and radula of Helix capitium Benson, 1848 and Helix onestera Mabille, 1887, the respective type species of Ganesella and Globotrochus. In addition, Ganesella rhombostoma (Pfeiffer, 1861) and Ganesella carinella (Möllendorff, 1902) from Thailand are re-described, and a new species, Ganesella halabalah Sutcharit & Panha, sp. nov., from southern Thailand is described. This new species differs from all others by having a larger shell, an obtuse apex and an aperture lip with a prominent beak-like deflection.


Introduction
The Camaenidae is one of the most speciose pulmonate snail families in Asia, and shows an astonishing diversity of taxa with different shell shapes, sizes and ecological characteristics (e.g., Pilsbry 1895, Solem 1959, Richardson 1985. Hitherto, camaenid taxonomy and classification has relied heavily on the shell morphology and, to a far lesser extent, on the reproductive anatomy. However, pulmonate shell characters are poor taxonomic markers as they often show convergent evolution and/or plastic features. The Camaenidae of Southeast Asia, including eastern India, Japan, Taiwan and southern China, are ground-dwelling or arboreal snails with relatively small to medium-sized, dextral or sinistral, trochoid shells. Traditionally, they were all assigned to the genus Ganesella W.T. Blanford, 1863. The (sub)generic name Ganesella was first coined without any description or definition to accommodate Helix capitium Benson, 1848 and Helix hariola Benson, 1856(Blanford 1863. As such, the definition of this (sub)genus has remained unclear (Zhou et al. 2011), the more so as the genital anatomy of Helix capitium was unknown until now (Schileyko 2003). Hence, the name Ganesella has been applied to a heterogeneous assemblage of what appears now to be at least four nominal subgenera (Thiele 1931, Zilch 1960, Richardson 1985. Unfortunately, there is little, if any, anatomical information on these (sub)genera.
The first data on the genital apparatus of Ganesella were published by Pilsbry (1895) for Helix japonica Pfeiffer, 1847, the type species of the genus Satsuma Adams, 1868. This genus was considered for a long time as a junior synonym of Ganesella (Pilsbry 1895, Thiele 1931, Zilch 1960). Yet, subsequent anatomical and molecular evidences have confirmed that Satsuma is to be treated as a distinct genus (Azuma 1995, Schileyko 2003, Wu et al. 2008, and is comprised of the species from Japan, Taiwan and southern China that were formerly assigned to Ganesella. As a consequence, the current interpretation of Ganesella confines this genus geographically to east of India and Southeast Asia. However, a general and consistent delimitation of Ganesella in terms of its genital features is still lacking, not in the least because the genital anatomy of its type species, Helix capitium was unknown until now (see below). Hence, species were assigned to Ganesella on the basis of shell characters only, and this has led to several misclassifications. A case in point is Ganesella brevibarbis (Pfeiffer, 1859) from China, which, after anatomical study, appeared to belong to the genus Plectotropis Martens, 1860 in the family Bradybaenidae (Albers 1860, Zhou et al. 2011. The recent revision of the Camaenidae by Schileyko (2003) has raised several subgenera of Ganesella to full genus rank (Liocystis Mörch, 1872, Coliolus Tapparone-Canefri, 1887, Coniglobus Pilsbry & Hirase, 1906and Globotrochus Haas, 1935, but this was still based only on shell characters. Hence, the first step towards a sound taxonomic revision of Ganesella in Indochina is to provide comparative anatomical data of the type species of the different genus-level taxa involved. The present study does so for the nominal genera Ganesella and Globotrochus, with their respective type species Helix capitium and Helix onestera Mabille, 1887. In addition, Ganesella rhombostoma (Pfeiffer, 1861) and Ganesella carinella (Möllendorff, 1902) from Thailand are re-described, and a new species from southern Thailand is described.

Materials and methods
Shells and living specimens were collected from various localities in Thailand and Vietnam. Live specimens were drowned in water and then fixed in 70% (v/v) ethanol for anatomical examination. Specimens were primarily identified using the publications of Benson (1848Benson ( , 1856, Pfeiffer (1853), Pilsbry (1891Pilsbry ( , 1895 and Möllendorff (1898), and were also compared with the relevant type material in museum collections (see below). To study anatomy, three to ten specimens were dissected under a stereomicroscope. Drawings were made with a camera lucida. Adult shells were used to measure the shell height (h) and shell width (w), and to count the number of whorls. Radulae were examined under scanning electron microscopy (SEM; JEOL, JSM-5410 LV).

Institutional
Genitalia typical of camaenids, without accessory organs on penis or vagina. Penis short to long, with small to large penial verge, but no penial appendix; epiphallus and flagellum short.
Remarks. The genus Ganesella s.s. differs from Satsuma s.s by having a penial verge, but no penial appendix. In contrast, Satsuma has a short to long penial appendix on the distal part of the penis, but lacks a penial verge. In addition, Satsuma occurs from Japan to Taiwan and southern China, while Ganesella occurs from South to Southeast Asia, including Japan (Azuma 1995, Schileyko 2003, Wu et al. 2008. Darwininitium shiwalikianum Budha & Mordan, 2012, the type species of the monotypic genus Darwininitium Budha & Mordan, 2012, appears conchologically identical to Helix capitium, the type species of Ganesella (see also Budha et al. 2016). Therefore, the genus Darwininitium, which was originally described from central Nepal, is here tentatively regarded as a junior subjective synonym of the camaenid genus Ganesella. If this is confirmed, then Darwininitium was erroneously assigned to the family Cerastidae and as such, its pallial system with a long kidney and s-shape ureter would point to a sigmurethrous condition and not to a case of pseudosigmurethry within the Orthurethra (sensu Solem 1959 and see also Budha et al. 2016). These taxonomic conclusions appear to be supported by DNA sequence data (Budha et al. 2016).
Shell and genitalia have been described in detail by Budha et al. (2012). The unique and distinctive characters of G. capitium are its small, relatively elevated, trochoid shell. Aperture open sublaterally. Whorls slightly convex with wide and shallow suture. Last whorl angular with weak peripheral keel. Shell colour brownish with whitish-opaque, irregular, spots or streaks. Genitalia with short atrium; cylindrical, short penis, about half as long as the vagina, and proximally with blackish, spongy tissue. Epiphallus and flagellum together short, about as long as the penis, but flagellum longer than epiphallus. Internal wall of penis with numerous longitudinal pilasters.  Fig. 2E).
Description. Shell small, dextral, thin and with a depressed trochoid. Apex acute; embryonic shell smooth with brownish colour. Whorls 5-6, increasing regularly, convex; suture wide and deep. Shell surface smooth or with fine growth lines. Last whorl large, very weekly angular to rounded; beneath convex; last whorl with brownish peripheral band. Shell brownish and translucent, with whitish-opaque, irregular streaks on upper and lower periphery. Aperture ovate; lip whitish and expanded; parietal callus transparent. Umbilicus rimate; columella whitish and expanded, overhanging umbilicus.
Remarks. The shells of Ganesella hariola, G. carinella and G. capitium have a trochoid shape, but the shell of G. capitium is clearly more elevated than the shells of the two other species. The shell of G. hariola differs further from that of G. capitium and G. carinella in having a deep suture and a rounded last whorl with a brownish spiral band on the periphery. In contrast, the shells of G. capitium and G. carinella have a shallow suture and an angular to keeled last whorl without a brownish peripheral band.  fig. 18. Blanford 1903: 278. Gude 1914: 196, 197. Zilch 1960: 610, fig. 2140. Zilch 1966: 202. Richardson 1985: 132, 133. Schileyko 2003: fig. 1958. Description. Shell. Shell small, dextral, thin and depressed trochoid. Apex acute; embryonic shell smooth with brownish colour. Whorls 5-6, increasing regularly, slightly convex and slightly shouldered near suture; suture wide and shallow. Shell surface smooth or with fine growth lines. Last whorl large, angular with strong keel; beneath convex. Shell brownish and translucent, with wide, whitish-opaque, irregular spiral band on upper and lower side. Aperture ovate; lip slightly expanded and whitish; parietal callus transparent. Umbilicus rimate with small hole; columella whitish and expanded overhanging umbilicus.
Genital organs. Atrium (at) short (N = 10) and proximally with blackish tissues. Penis (p) cylindrical, about as long as the vagina; proximally blackish; distally slightly enlarged at penial verge. Epiphallus (e) and flagellum (fl) very short, approximately one-third of penis length. Vas deferens (vd) long and narrow, extends from free oviduct and terminates at distal epiphallus. Penial retractor muscle (pr) long and thin. Flagellum short, as long as or longer than epiphallus (Fig. 5A).
Penial verge (pv) small, conical, and with smooth surface. Penial wall ribbed, forming a series of swollen longitudinal pilasters (pp); middle wall with very thin pilasters. Pilasters swollen in the distal portion of penial chamber (Fig. 5B).
Jaw crescent, with anterior convex cutting margin. Vertical ribs prominent, and variable in number and size (Fig. 5D).
Pallial system. Typical sigmurethran; heart (au and ve) located left of kidney (on right in Fig. 5C). Pulmonary cavity approximately 5× longer than wide. Pulmonary vein (puv) and venation on lung roof (l) distinct and well developed. Kidney (k) long, slender and extending from posterior side to approximately the middle of pulmonary  cavity. Ureter (ur) is a sigmoid, closed tube arising from apex of kidney, extending along right side of kidney, recurving near rectum (r). Rectal opening adjacent to anus (a) and pneumostome (pn) (Fig. 5C).
Remarks. Hitherto, Ganesella carinella was regarded as a junior synonym of G. capitium. However, after Budha et al. (2012) described the genital apparatus of conchologically typical G. capitium, it became clear that G. carinella differs from the type species not only by having a more depressed shell with a strong peripheral keel but also by its longer penis and epiphallus, and its shorter vagina. In contrast, G. capitium has a more elevated trochoid shell, an angular last whorl, a shorter penis and epiphallus, and a longer vagina.
Ganesella carinella shows considerable variation in shell shape and colour. For example, specimens from Lopburi (Fig. 3A) tend to be paler and have a more descending aperture than specimens from Saraburi. Specimens from Chiangmai (Fig. 3B) tend to have more whitish spots on their shell than specimens from Lopburi and Saraburi. Yet, this conchological variation is not matched by consistent genital differences. Therefore, we conclude that the shell variation within this widely-distributed species only involves intraspecific polymorphism.
Vaginal wall with several smooth, longitudinal pilasters; vaginal wall itself with strong longitudinal ridges through the vaginal chamber (Fig. 5F).
Jaw crescent, with anteriorly convex cutting margin. Vertical ribs thin, and variable in number and size (Fig. 5G).
Distribution. This species was formerly known from its type locality in Cambodia (Morlet 1889(Morlet , 1890 and some inaccurate localities recorded from Vietnam (Schileyko 2011). In Thailand, it is known from several localities in Chachoengsao, Srakeo and Chanthaburi Provinces.
Remarks. Ganesella rhombostoma has long been overlooked and its taxonomic status has been unclear. The species has been erroneously assigned to Amphidromus Albers, 1850and Giardia Ancey, 1907(see Dautzenberg and Fischer 1906, Schileyko 2011). Yet, its trochoid shell and sub-ventrally opening aperture show that it belongs to neither of these genera, since Giardia (type species Bulimus siamensis Redfield, 1853) and Amphidromus (type species Helix perversus Linnaeus, 1758) have an elongate, ovate shell, a non-deflected last whorl, an ovate and laterally opening aperture, and a narrowly opened umbilicus (see also Schileyko (2003) and Sutcharit and Panha (2006) for further comparisons). Moreover, the anatomical evidence presented here suggests that this species rather belongs to Ganesella. However, the relationships between Ganesella and Giardia needs further investigation by molecular analysis.
Specimens from isolated limestone outcrops at Khao Maka, Chacheongsao are smaller and have a more ovate shell without a brownish spiral band on of the last whorl (Fig. 3G). However, anatomically they are indistinguishable from typical G. rhombostoma and, therefore, they are considered conspecific. Type locality. Sirindhorn Waterfall, Hala-Bala Wildlife Sanctuary, Waeng District, Narathivat Province, Thailand.

Ganesella halabalah
Diagnosis. The dextral, large, trocoid shell with pale green to yellow colour, obtuse apex and apertural lip with prominent beak-like deflection.
Description. Shell. Shell medium-sized (height 23.6 mm, width 25.1 mm), thin, dextral and trochoid. Apex obtuse; embryonic shell smooth and black. Whorls 5-6, increasing regularly, smooth; suture wide and shallow; shell surface with thin growth lines. Last whorl large, with well-developed peripheral keel and blunt at lower periphery. Shell colour pale green or yellow to monochrome creamy; earlier whorls paler; with or without brown spiral band on peripheral keel and lower periphery. Periostracum thin corneous, brownish and translucent. Aperture relatively large, semi-ovate; parietal callus transparent; columella wide and whitish. Apertural lip expanded, whitish, and angled with prominent beak-like deflection at peripheral keel. Umbilicus rimate and partially obscured by lower apertural lip. Etymology. The specific name is derived from the type locality Hala-Bala Wildlife Sanctuary, Narathivat, Thailand.
Distribution. This new species is currently known from the type locality (in Narathivat, Thailand) and Gunung Tahan, Kelantan, Malaysia, which is about 150 km south of the type locality. The latter shell (Fig. 4C) was collected in 1901 in a tropical rain forest. This shell is in all aspects identical to the unique name-bearing type.
Remarks. Even though Ganesella halabalah sp. nov. is described from empty shells, its unique features mean that it cannot be confused with any other camaenid species from the area. Yet, with its trochoid shell and its prominent, beak-like apertural rostrum, G. halabalah sp. nov. does resemble a Papuininae phenotype. However, the geographic distribution of the Papuininae is largely restricted to New Guinea, Australia and Melanesia (Schileyko 2003), though excluding the Greater Sunda Islands and Indochina. Given that the Malay Peninsula is a remote area for land snail dispersal between Australasia and Indochina (Hausdorf 2000), further anatomical and molecular evidence is needed to assess an eventual relationship with Papuininae.
This new species clearly differs from all Ganesella and other land snail species known in Indochina. The most similar species is Ganesella perakensis (Crosse, 1879) from Malaysia, which has a much smaller (average shell height < 10 mm), thin shell, and a simple apertural lip (Fig. 4D). Ganesella halabalah sp. nov. has a larger shell (average shell height > 20 mm), an obtuse apex and an aperture lip with a typical, prominent beak-like deflection.
The new species also differs from all Kenyirus Clements & Tan, 2012 species from Malaysia by having a conical spire, yellowish shell and narrower umbilicus. While K. sodhii Clements & Tan, 2012 has a depressed spire, long spout-like apertural rostrum on the peripheral keel, and 3-4 brownish spiral bands on the last whorl. In comparison K. sheema Foon et al., 2015 has subglobose shell, an angular last whorl, and with two brownish spiral bands below the periphery; while K. balingensis Tan et al., 2017 has a smaller and brownish shell.
Description. Shell trochoid, thin, translucent, 4-6 slightly convex whorls. Last whorl angulated or carinated, slightly descending in front. Colour light yellowishbrown. Embryonic shell smooth. Post apical whorls with irregular, thin, radial ridges and spiral line (smooth below peripheral angle or keel). Aperture ovate, moderately oblique, with slightly expanded and reflexed margins. Umbilicus closed. Shell height ranged from 16 to 17 mm and shell width ranged from 21 to 22 mm. Genitalia typical of camaenids, but with thin (small size and fully functional) male genital organs (penis and epiphallus).
Radular teeth triangular and tricuspid. Remarks. The weak development of male genitalia in Globotrochus is unusual among the Indochinese taxa, but is common in papuinid genera, such as Papustyla Pilsbry, 1893, Letitia Iredale, 1941, Papunella Clench & Turner, 1959and Wahgia Clench & Turner, 1959(Schileyko 2003. However, Papuininae are geographically confined to New Guinea, Australia and Melanesia (Schileyko 2003), and have never been recorded in Indochina. Therefore, it seems as if 'weak male genital parts' is an autapomorphy of Globotrochus.
Globotrochus differs from all other camaenid genera in Indochina (i.e., Chloritis, Satsuma, Ganesella and Neocepolis) by its weakly developed male genital organs. In contrast, the genera Chloritis, Ganesella and Neocepolis have typical camaenid genitalia, with well-developed male genital organs, including a relatively short to long penis, an epiphallus and penial verge, and a short to long flagellum. Furthermore, Ganesella has no penial appendix. Satsuma has a fully-developed male genital organ, with a short to long penial appendage, but without a penial verge (Solem 1993, Schileyko 2003, 2004, Sutcharit et al. 2007, Sutcharit and Panha 2010. Currently, only two nominal species are assigned to Globotrochus. Based on the literature, museum specimens and recent field surveys, it seems as if Globotrochus is restricted to the north of Vietnam (Vermeulen and Maassen 2003, Schileyko 2003, 2011. However, an ambiguous locality record from Elephant Mountain, Laos (sensu Schileyko 2011: 46) needs verification.

Type locality. Tonkin [north Vietnam].
Material examined. Type material. This species was described on the basis of shells from the Balansa coll. Mabille (1887b: 89, 90, pl. 2, figs 4, 5) re-published the description of the species with an illustration of a shell. The MNHN-Malacologie collection contains two lots with syntypes. The first lot is from the Balansa coll. and consists of two shells with an original label giving the taxon name, collection locality and marked with the word "M. Balansa 1887. Type". One of the two shells is not damaged and its size closely matches the measurements in the original description and the illustration of Mabille (1887b: pl. 2, figs 4, 5). This shell is, therefore, here designated as the lectotype MNHN-IM-2000-32456/1 (Fig. 4E, height 15.1 mm, width 20.5 mm, 5 whorls). The second shell is broken up into three pieces and becomes the paralectoype MNHN-IM-2000-32456/2 (1 shell). The second lot MNHN-IM-2000-2073 consists of a shell with the marking "Type" on its label. Yet, this lot does not belong to the Balansa collection and was subsequently labeled as "H. onestera J. Mab. var.". Therefore, we exclude this lot from the type series of this nominal species (ICZN 1999: Art. 72 Description. Shell. Shell medium-sized, dextral, thin and trochoid. Apex acute; embryonic shell smooth with brownish colour. Whorls 5-6, increasing regularly, slightly convex and slightly shouldered near suture; suture wide and shallow. Shell surface smooth or with fine growth lines. Last whorl large, angular with strong keel, beneath slightly convex. Shell monochrome, light brownish and translucent. Aperture semiovate; lip slightly expanded and brownish; parietal callus thin. Umbilicus closed; columella small and whitish. Genitalia. Male genital organ (N = 3) thin (small size and fully function). Atrium (at) short, about as long as penis. Penis (p) short, proximally cylindrical, distally like a short, but wider tube. Penial sheath and penial verge absent. Epiphallus (e) small, as long as penis; flagellum absent. Vas deferens (vd), short, narrow, extending from free oviduct to tip of epiphallus. Penial retractor muscle (pr) relatively thin and long (Fig. 6A).
Internal walls of vagina with several smooth surfaces of longitudinal pilasters (vp). Vaginal wall itself with strong longitudinal ridges through the vaginal chamber (Fig. 6B).
Radula. Teeth arranged in anteriorly pointed, nearly straight rows, each row containing about 79 (39-1-39) teeth. Central tooth symmetric tricuspid, mesocone large with pointed cusp, ectocone very small and located in the middle of tooth. Lateral and marginal teeth undivided. Inner teeth (no. 1-14) asymmetric tricuspid, endocone and ectocone small, and mesocone large with pointed cusp (Fig. 7G, H). Outermost teeth tricuspid, endocone small and located close to apex of teeth; mesocone relatively large with curved cusp, and ectocone located at base and cusps sometimes split into two pointed cusps (Fig. 7H, I).
Jaw crescent, with anteriorly convex cutting margin. Vertical ribs prominent, variable in number and size (Fig. 6D). Pallial system. Typical sigmurethran; heart (auricle and ventricle) located left of kidney (on right in Fig. 6C). Pulmonary cavity approximately 5× longer than wide. Pulmonary vein and venation on lung roof distinct and well developed. Kidney elongated, slender and extending from posterior side of cavity to approximately half of pulmonary cavity. Ureter sigmoidal, closed tube arising from apex of kidney, extending along right side of kidney, recurving adjacent to rectum. Rectal opening adjacent to anus and mantle collar (Fig. 6C).
Distribution. This species is known from the type locality and recent records from Cuc Phuong National Park, Ninh Binh, and Nui Con Vui near Hai Phong, in northern Vietnam (Schileyko 2011).
Remark. Live specimens of this species were collected for the first time in 2006 at Cuc Phuong, Vietnam. This is a very humid area with tropical forest patches and limestone karst. The snails were collected on small shrubs, suggesting that it may be an arboreal species.
Recently, Thach (2017) described a new species from Vietnam under the southern Pacific Islands endemic genus Diastole Gude, 1913(see Schileyko 2002. The species Diastole simonei Thach & Huber, 2017 was described from the same geographical area as Globotrochus onestera, the original description of which did not mention this species. The type specimens of Globotrochus onestera and Diastole simonei are identical in all characters. Hence, we treat Diastole simonei Thach & Huber, 2017 as a junior subjective synonym of Globotrochus onestera.
Remark. Globotrochus mellea is similar to Globotrochus onestera in almost all shell characters, except for its larger last whorl, strong angular peripheral keel and more depressed trochoid shell. Therefore, we provisionally retain Globotrochus mellea as a distinct species.
Center of Excellence on Biodiversity BDC-PG2-160012, and the Darwin Initiative Project no. 14-653. We also thank the anonymous reviewers for critically reviewing the manuscript.