Research Article
Print
Research Article
Uncovering local endemism from southeastern Myanmar: description of the new karst-associated terrestrial snail genus Burmochlamys (Eupulmonata, Helicarionidae)
expand article infoArthit Pholyotha‡, Chirasak Sutcharit‡, Aung Lin§, Somsak Panha|‡
‡ Chulalongkorn University, Bangkok, Thailand
§ Fauna and Flora International, Sanchaung Township, Yangon, Myanmar
| Academy of Science, The Royal Society of Thailand, Bangkok, Thailand

Corresponding author: Somsak Panha ( somsak.pan@chula.ac.th )

Academic editor: Martin Haase
© 2022 Arthit Pholyotha, Chirasak Sutcharit, Aung Lin, Somsak Panha.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Pholyotha A, Sutcharit C, Lin A, Panha S (2022) Uncovering local endemism from southeastern Myanmar: description of the new karst-associated terrestrial snail genus Burmochlamys (Eupulmonata, Helicarionidae). ZooKeys 1110: 1-37. https://doi.org/10.3897/zookeys.1110.82461
ZooBank: urn:lsid:zoobank.org:pub:01302157-EE40-4B99-99DD-3EC3377D929C
Open Access

Abstract

Salween River basin’s karst ecosystems in southeastern Myanmar remain largely unexplored and are likely to harbour a high terrestrial snail diversity that are often associated with high levels of snail endemism. Here, an outstanding group of new karst-associated terrestrial snails, Burmochlamys gen. nov., are discovered. A study of the comparative morphological and anatomical data reveals that the reproductive tract and radula of this new genus are closely related to the helicarionid genus Sophina Benson, 1859 but shell morphology (shape, size, and sculpture) and mantle extensions are distinct from the latter genus. Burmochlamys gen. nov. now consists of four known nominal species, B. cassidula comb. nov., B. cauisa comb. nov., B. perpaula comb. nov., and B. poongee comb. nov., and five new species; B. albida sp. nov., B. fasciola sp. nov., B. moulmeinica sp. nov., B. versicolor sp. nov., and B. whitteni sp. nov. The highlight is that the members of the new genus show site-specific endemism, being restricted to karstic habitat islands of the Salween River basin. In addition, the discovery supports that the unique and complex structure of Salween River basin’s karst ecosystems are habitats in which the terrestrial malacofauna have speciated and become endemic.

Keywords

Diversity, endemic, Indochina, land snail, limestone, Salween River basin, taxonomy

Introduction

Myanmar is globally recognised as a highly important biodiversity hotspot that supports a great number of several endemic species of animals (Myers et al. 2000; Grismer et al. 2018a, b; Sutcharit et al. 2020). Especially the Salween River basin located in the southeastern Myanmar has a wide diversity of limestone hills and outcrops surrounded by lowland areas that are temporarily flooded during the monsoon season (Figs 1, 2) that can form island-like habitats (Clements et al. 2006; Grismer et al. 2018a, b, 2021; Sutcharit et al. 2020). The Salween River basin’s karst ecosystems also serve as foci for speciation and endemism of the terrestrial malacofauna (Sutcharit et al. 2020) as well as geckos (Grismer et al. 2018a, b). Under these conditions, it is no surprise that although there have been several documentations of land snail fauna over many years, including Benson (1859), Theobald (1859), Stoliczka (1871), Godwin-Austen (1882–1920), Blanford and Godwin-Austen (1908), Pholyotha et al. (2020b), and Sutcharit et al. (2020), a large proportion of land snail fauna still remains undescribed. On the other hand, many known taxa from the region also need to be re-investigated because the current classification does not include any distinguishing characteristics, especially the genitalia, to achieve a more reliable generic classification level.

Figure 1. 

Map of the Salween River basin (known as Thanlwin River) in the southeastern Myanmar showing the sampling sites. Coloured triangles indicate the localities recorded for each Burmochlamys species. White circles indicate the localities recorded for Sophina species. White squares indicate the sampling localities with no records of both Sophina and Burmochlamys species.

Figure 2. 

Habitat of some species of Burmochlamys gen. nov. in the karst basin of Hpa-An, Kayin State, Myanmar. A type locality of B. fasciola sp. nov. at Bardai Mountain and microhabitat structure of the karst wall B newly discovered locality of B. poongee at Kaw Ka Thaung Cave C type locality of B. albida sp. nov. at Waiponla Monastery D type locality of B. moulmeinica sp. nov. at Lun Nya Pagoda E type locality of B. versicolor sp. nov. at Bayin Nyi Cave. Photos by Ruttapon Srisonchai.

One group of snails with a small, depressed to conical, and rounded body whorl constitutes a distinctive part of the southeastern Burmese fauna (Stoliczka 1871; Blanford and Godwin-Austen 1908; Sutcharit et al. 2020). However, shell-based taxonomy of the group is insufficient for generic classification where the generally conserved shell form has created long-lasting taxonomic confusion. There are many genera of the speciose limacoid families in the Helicarionidae Bourguignat, 1877 (i.e., Sophina Benson, 1859) and Ariophantidae Godwin-Austen, 1883 (i.e., Macrochlamys Gray, 1847 and Microcystina Mörch, 1872) that present these shell morphs (Blanford and Godwin-Austen 1908; van Benthem Jutting 1950; Solem 1966; Schileyko 2002, 2003; Vermeulen et al. 2019; Pholyotha et al. 2020b; Sutcharit et al. 2020). Fortunately, the morphological characters of the mantle extensions, radula, and genitalia can distinguish between all these genera. In addition, integrative systematic revision of several Southeast Asian helicarionoids (i.e., Páll-Gergely et al. 2016; Pholyotha et al. 2020a, b, c, 2021a, b; Sutcharit et al. 2020, 2021) and the Australian helicarionids (i.e., Hyman et al. 2017; Hyman and Köhler 2018) confirms the taxonomic importance of these characters.

After intensive sampling from karstic and non-karstic habitats in southeastern Myanmar, the two overlooked species, Helix poongee Theobald, 1859 and Helix cassidula Benson, 1859, were found and showed a surprising incongruence in the radular and genital morphology that prevented their classification into the current known genus Macrochlamys (Blanford and Godwin-Austen 1908; Pholyotha et al. 2018, 2020b). In this survey, additional undescribed species of small-sized snails were also found. Noticeably, all seven species are likely to be the intermediate form to several genera because they have a mantle morphology similar to those of Macrochlamys, a small-sized shell with a spiral striated shell sculpture like Microcystina, and spatulate radula teeth identical to those of Sophina. Despite the absence of a molecular framework, the morphology-based revision has been widely accepted and could greatly contribute to a more robust taxonomy of the Asian helicarionoids (Solem 1966; Páll-Gergely et al. 2016; Vermeulen et al. 2019; Pholyotha et al. 2020a, b, c, 2021a, b; Sutcharit et al. 2020, 2021). Therefore, in this study, we describe a new land snail genus Burmochlamys gen. nov. together with the re-description of the two known species: Helix poongee and H. cassidula and five newly described species based on the comparative morphological and anatomical dataset. This discovery has also highlighted the growing knowledge of the diverse and endemic terrestrial snail fauna in Myanmar.

Materials and methods

Sampling, material preserving, identification, and morphological examination

Land snails were collected by direct visual searching and hand collecting from several accessible localities, including limestone and non-limestone habitats, from Shan State, Mon State, Kayin State, and the Tanintharyi Region; however, only the limestone area of the Salween River basin in southeastern Myanmar was found to house populations of Burmochlamys species (Fig. 1). Field surveys were conducted during the years 2015 to 2016 under an MOU between the Forest Department, Ministry of Natural Resources and Environmental Conservation and Forestry, Myanmar, and Fauna & Flora International. Prior to preservation of the collected specimens in the field, we took pictures of each individual species in life. Snails were then euthanised following the standard two-step method protocols (American Veterinary Medical Association 2020), and then preserved in 95% (v/v) ethanol for further morphological and molecular works. The animal use protocol was approved by the Chulalongkorn University Animal Care and Use Committee (CU-ACUC) under the approval number 1723018. Type material and other voucher specimens are deposited in the Chulalongkorn University Museum of Zoology (CUMZ), Bangkok, Thailand and additional paratype specimens are deposited at the Natural History Museum, London, United Kingdom (NHM or NHMUKwhen citing specimen lots deposited in the NHM). Species identification was made based on the current literature [i.e., Benson (1859), Theobald (1859), Stoliczka (1871), Blanford and Godwin-Austen (1908), Pholyotha et al. (2020b), and Sutcharit et al. (2020)], and then compared with the available reference collection of the NHM and the University Museum of Zoology, Cambridge (UMZC). For the descriptive work, adult shells and genitalia were imaged using a Nikon camera (DSLR D850) with a Nikon 105 Macro lens (AF-S VR Micro-Nikkor 105 mm f/2.8G IF-ED). Adult shells were measured for size using a Vernier caliper and counting the number of whorls. Three to ten specimens of each species were dissected and examined under an Olympus SZX2-TR30 stereoscopic light microscope. Radulae were extracted, soaked in 10% (w/v) sodium hydroxide, cleaned with distilled water, and then imaged by scanning electron microscopy (SEM; JEOL, JSM-6610 LV).

List of abbreviations used in the figures: ant-ldl (anterior left dorsal lobe), at (atrium), cf (caudal foss), >ch (caudal horn), da (dart apparatus), e1 (portion of epiphallus nearer to penis), e2 (portion of epiphallus nearer to retractor muscle), ec (epiphallic caecum), fo (free oviduct), gd (gametolytic duct), gs (gametolytic sac), lsl (left shell lobe), p (penis), post-ldl (posterior left dorsal lobe), prm (penial retractor muscle), rdl (right dorsal lobe), rsl (right shell lobe), v (vagina),vd(vas deferens).

Systematic descriptions

Family Helicarionidae Bourguignat, 1877

Subfamily Durgellinae Godwin-Austen, 1888

Burmochlamys Pholyotha & Panha, gen. nov.

https://zoobank.org/060B5C90-76D8-44D5-96CC-924066E94F59

Type species

Burmochlamys fasciola sp. nov., by original designation.

Etymology

The name combines Burmo in reference to Burma, the historical name of Myanmar, and the Greek word chlamys meaning mantle or cloak in reference to land snail with well-developed mantle extensions. Therefore, the generic name means the Burmese land snail with the well-developed mantle extensions. The gender of the new generic name is feminine.

Diagnosis

Shell subglobose to globose, small size, little high spire, and sculptured with spiral furrows and undulating radial lines. Snail with five well-developed mantle extensions; caudal horn raised. Genitalia with penial retractor muscle attached at tip of epiphallic caecum; gametolytic organ with rather short to moderate cylindrical duct and bulbous sac; well-developed dart apparatus; flagellum absent. Radula with large monocuspid central tooth and attached by two smaller teeth; laterals and marginals undifferentiated, large monocuspid, and at base of each tooth on outer side attached by a smaller tooth.

Description

Shell subglobose to globose, small-sized, thin, whitish to brownish, with or without yellowish brown band on the periphery. Shell surface with distinct to faintly spiral furrows, crossed by distinct to faintly undulating radial lines. Whorls 5½–7, regularly increasing; spire rather elevated; body whorl rounded. Aperture oblique and crescentic with simple lip. Umbilicus open, narrow to moderate, and deep.

Animal reticulated skin with pale to dark greyish or with a brown or yellow tinge. Mantle lobes or mantle extension well developed, divided into two shell lobes and three dorsal lobes, and somewhat thickened near their margins (Fig. 3A–C). Shell lobes short to moderate, slender, finger-like, and same colour as body. Right shell lobe (rsl) rather longer and larger than left shell lobe (lsl). Dorsal lobes large, broad, normally larger than shell lobes, crescent-shaped, and same colour as body. Right dorsal lobe (rdl) larger than left dorsal lobe. Left dorsal lobe divided into anterior (ant-ldl) and posterior lobes (post-ldl). Sole tripartite and lateral foot margin present. Caudal foss (cf) and caudal horn (ch) present (Fig. 3B).

Figure 3. 

Synoptic illustration of mantle extensions, body terminology and radular morphology of Burmochlamys gen. nov. A right and left shell lobes of B. fasciola sp. nov. B mantle extensions (shell lobes and dorsal lobes) and posterior body of B. poongee C dorsal view of mantle extensions (shell lobes and dorsal lobes) of B. cassidula D, E representative SEM images of radula showing monocuspid central tooth (yellow) and lateromarginal teeth (blue) attached by the smaller triangular-shaped teeth (red). White arrow indicates pneumostome or breathing pore. Yellow arrow indicates a tiny cusp on outermost lateromarginal teeth.

Genitalia possess penis with thin penial sheath; penial retractor muscle varying in size and attached at tip of short and straight epiphallic caecum. Flagellum absent. Dart apparatus present. Gametolytic organ with rather short to moderate cylindrical duct and bulbous sac.

Radular teeth arranged in wide U-shaped rows. Central tooth monocuspid, large, narrow to broad spatulate shape, and with two smaller triangular-shaped teeth located at base (Fig. 3D). Lateral and marginal teeth not differentiated, monocuspid, large spatulate shape, and with only one smaller triangular-shaped tooth located at base on outer side. From inner to outer, lateromarginal teeth gradually narrower, smaller, and rather pointed cusp (Fig. 3D, E), and tiny inner cusp sometimes present on outermost teeth (yellow arrow in Fig. 3E).

Constituent species

Burmochlamys gen. nov. currently contains: B. cassidula (Benson, 1859), comb. nov., B. cauisa (Benson, 1859), comb. nov., B. perpaula (Benson, 1859), comb. nov., B. poongee (Theobald, 1859), comb. nov., B. albida sp. nov., B. fasciola sp. nov., B. moulmeinica sp. nov., B. versicolor sp. nov., and B. whitteni sp. nov.

Distribution

Burmochlamys gen. nov. shows a remarkable degree of endemism and localisation being restricted to the limestone karsts in the south of Salween River basin, Myanmar (Fig. 1). The limestone formations in the region are notable for their fragmented, island-like nature, with hills, caves, and towers forming archipelagos of habitat islands and some areas are temporarily flooded during the monsoon season (Fig. 2).

Remarks

Burmochlamys gen. nov. possesses a similar radular morphology (monocuspid and spatulate shape) to those of Aenigmatoconcha Tumpeesuwan & Tumpeesuwan, 2017, Chalepotaxis Ancey, 1887, and Sophina. However, the new genus is easy to distinguish from these three genera by having a microscopic shell sculpture, slender mantle extensions (left and right shell lobes) and genitalia with a well-developed dart apparatus and without a flagellum. In contrast, those three genera have a smooth shell surface and well-developed left and right shell lobes that can be enlarged and cover most of the shell. The genitalia of Sophina is more similar to that of Burmochlamys gen. nov., while Aenigmatoconcha has a small flagellum and no dart apparatus, and Chalepotaxis has neither flagellum nor dart apparatus (Páll-Gergely et al. 2016; Sutcharit et al. 2020; Pholyotha et al. 2021b).

In addition, Burmochlamys gen. nov. is clearly discriminated from other helicarionid and ariophantid genera with or without shell lobes by the presence of the monocuspid radular teeth (see Table 1). In comparison, the radular morphology of most genera in these families possess bicuspid, tricuspid, or multicuspid teeth (Stoliczka 1871; Blanford and Godwin-Austen 1908; van Benthem Jutting 1950; Solem 1966; Schileyko 2002, 2003; Páll-Gergely et al. 2016; Sutcharit et al. 2020; Pholyotha et al. 2021b).

Table 1.
Download as
CSV
XLSX

Comparison of the morpho-anatomical characteristics of Burmochlamys gen. nov. and the possibly related genera of the Helicarionidae and Ariophantidae in mainland Southeast Asia. References: 1 = this study, 2 = Stoliczka (1871), 3 = Blanford and Godwin-Austen (1908), 4 = van Benthem Jutting (1950), 5 = Solem (1966), 6 = Schileyko (2002), 7 = Schileyko (2003), 8 = Páll-Gergely et al. (2016), 9 = Tanmuangpak et al. (2017), 10 = Pholyotha et al. (2018), 11 = Pholyotha et al. (2020b), 12 = Pholyotha et al. (2020c), 13 = Pholyotha et al. (2021a), 14 = Pholyotha et al. (2021b), and 15 = Sutcharit et al. (2020).

Shell size (diameter) Periphery Shell lobe Radula teeth Epiphallic caecum Flagellum Dart apparatus Ref.
Family Ariophantidae Godwin-Austen, 1883
Khasiella Godwin-Austen, 1899 (Helix vidua Hanley & Theobald, 1876)* small to medium keeled or subangulate short, slightly extended central tricuspid, lateral tricuspid, marginal bicuspid free bent present present 3,6
Macrochlamys Gray, 1847 (Helix vitrinoides Deshayes, 1831) small to large round or anglulate moderate to long, slender central tricuspid, lateral tricuspid, marginal bicuspid coiled present present 3, 7, 10, 11
Microcystina Mörch, 1872 (Nanina rinki Mörch, 1872)* small round short to moderate, slender central tricuspid, laterals tricuspid, marginals bicuspid absent absent present1 3, 4, 7
Sakiella Godwin-Austen, 1908 (Helix honesta Gould, 1846)* medium subangulate moderate, slender central tricuspid, lateral tricuspid, marginal bicuspid n.a. n.a. present 2, 3, 7
Sarika Godwin-Austen, 1907 (Helix resplendens Philippi, 1847)* medium to large round or angulate moderate to long, slender central tricuspid, lateral tricuspid, marginal bicuspid straight present present 3, 11, 6, 12
Sesara Albers, 1860 (Helix infrendens Gould, 1843)* small to medium round, angulate, or carinate absent central tricuspid, lateral tricuspid, marginal bicuspid straight2 present absent 2, 3, 5, 6, 9
Taphrenalla Pholyotha & Panha, 2020 (Nanina diadema Dall, 1897)* medium to large round long, slender central tricuspid, lateral tricuspid, marginal bicuspid straight to little bent present present 13
Taphrospira Blanford, 1904 (Helix convallata Benson, 1856) medium round long and fairly broad, covering partially central tricuspid, laterals tricuspid, marginals bicuspid straight present absent 3, 6
Family Helicarionidae Bourguignat, 1877
Aenigmatoconcha Tumpeesuwan & Tumpeesuwan, 2017 (Aenigmatoconcha clivicola Tumpeesuwan & Tumpeesuwan, 2017)* medium round long, broad, enlarged and covering most of shell central monocuspid, lateromarginal monocuspid straight present absent 14
Chalepotaxis Ancey, 1887 (Helix similaris var. infantilis Gredler, 1881)* small to medium round long, broad, enlarged and covering most of shell central monocuspid, lateromarginal monocuspid straight absent absent 8
Cryptaustenia Cockerell, 1891 (Vitrina planospira Benson, 1859 (= Vitrina succina Reeve, 1862))* small to medium round long, broad, enlarged and covering most of shell central tricuspid, lateral bi- or tricuspid, marginal bicuspid absent absent present3 3, 5, 7
Durgella Blanford, 1863 (Helix levicula Benson, 1859)* small to medium round long, broad, enlarged and covering most of shell central unicuspid, lateromarginal teeth bicuspid with numerous cusps on the outer side straight absent present4 3, 5, 6
Holkeion Godwin-Austen, 1908 (Helix anceps Gould, 1843)* medium to large sharply angulate short to moderate, slender central tricuspid, lateral tricuspid, marginal bicuspid absent present present 3,7
Sitala Adams, 1865 (Helix infula Benson, 1848)* small to medium subangulate or carinate short, slightly extended central tricuspid, lateromarginal teeth pointed with 2–5 cusps on the outer side straight absent absent5 2,3
Sophina Benson, 1859 (Helix schistostelis Benson, 1859)* small to medium round long, broad, enlarged and covering most of shell central monocuspid, lateromarginal monocuspid straight absent present 2,3,15
Burmochlamys gen. nov. (Burmochlamys fasciola sp. nov.)* small round short to moderate, slender central monocuspid, lateromarginal monocuspid straight absent present 1

* Genitalia of the type species were examined. 1 Microcystina bintennensis Godwin-Austen, 1899 does not have dart apparatus (see Blanford and Godwin-Austen 1908). 2 Sesara parva Solem, 1966 has a spirally coiled epiphallic caecum (Solem 1966). 3 Cryptaustenia gadinodromica Solem, 1966 does not have dart apparatus (Solem 1966). 4 Durgella assamica Godwin-Austen, 1881 and D. rogersi Godwin-Austen, 1907 do not have dart apparatus (Blanford and Godwin-Austen 1908). 5 Sitala attegia (Benson, 1859) has a well-developed dart apparatus (Stoliczka 1871; Blanford and Godwin-Austen 1908).

As observed in the field, we searched after rain and found the snails climbing on the limestone walls or hiding under the slope of rocks (Fig. 4A). Regarding the simultaneous hermaphroditism, many copulating pairs were also discovered (Fig. 4B). Information on its natural predators and parasites remains scarce, but the carnivorous streptaxid snails were found sympatrically in some localities (Fig. 4C, D).

Figure 4. 

A adult of B. moulmeinica sp. nov. while climbing slowly on the karst wall after raining at Lun Nya Pagoda B mating pairs of B. versicolor sp. nov. on the karst wall at Bayin Nyi Cave C B. versicolor sp. nov. eaten by the carnivorous snail Carinartemis sp. on the karst wall at Bayin Nyi Cave D B. cassidula eaten by the carnivorous snail Haploptychius sp. on the karst wall at Kaw Gon Cave.

Burmochlamys cassidula (Benson, 1859), comb. nov.

Figs 1, 3C, 4D, 5B, 6A, B, 8A–C, 9A, 11A

Helix cassidula Benson, 1859: 186. Type locality: ad Moulmein, nee raro [Mawlamyine, Mon State, Myanmar].

Hyalinia cassidula — Tryon, 1886: 177, pl. 53, fig. 68.

Material examined

Type material. Moulmein: probable syntype UMZC I.104235.

Other material

Kaw Gon Cave, Hpa-An, Kayin State, Myanmar (16°49'22.2"N, 97°35'08.9"E): CUMZ 14209 (Fig. 6A, B).

Diagnosis

Shell globose, milky white with yellow tinge, and with wide yellowish brown band. Animal greyish with five mantle extensions. Genitalia with very short epiphallic caecum attached by thin penial retractor muscle, very short and large vagina, and short and large gametolytic duct.

Description

Shell (Figs 6A, B, 8A–C). Shell globose, small (width up to 7.8 mm, height up to 6.3 mm), rather thin, semi-translucent. Colour milky-white with yellow tinge with wide yellowish brown band above periphery. Protoconch and teleoconch surface with similar sculpture. Surface of body whorl with distinct spiral furrows at regular intervals, cut by distinctly undulating radial lines (Fig. 8A–C). Whorls 6–6½, increasing regularly; suture impressed; spire much elevated; varix usually present; last whorl rounded on periphery, and little convex below. Aperture obliquely crescent-shaped; peristome simple. Columellar margin simple and slightly reflected near umbilicus. Umbilicus open, narrow, and deep.

Genital organs (Fig. 9A). Atrium (at) very short. Penis (p) rather short, cylindrical, and with a penial sheath. Epiphallus (e1+e2) ca. three-quarters of penis length; e1 cylindrical and its diameter smaller than penis and e2; e2 bulbous and ca. half of e1 length. Epiphallic caecum (ec) very short, cylindrical and with thin penial retractor muscle (prm) attached at tip. Vas deferens (vd) thin tube. Dart apparatus large, rather long cylindrical, and located on atrium at vagina and penis junction. Vagina (v) large, very short, and cylindrical. Gametolytic sac (gs) bulbous; gametolytic duct (gd) short, ca. one-quarter of penis length, cylindrical, and very enlarged near vagina. Free oviduct (fo) as long as penis, cylindrical, and encircled with thick tissue near vagina.

Radula (Fig. 11A). Teeth arranged in wide U-shaped rows with each row consisting of ~ 75 teeth. Central tooth monocuspid, large and ovate spatulate shape, with two smaller triangular-shaped teeth located at base of central tooth. Laterals and marginals not differentiated, monocuspid, large spatulate shape then gradually become narrower, elongated and rather pointed cusp. One smaller triangular-shaped tooth located at base on outer side of each tooth, and then gradually reduced in size outwards. Some outermost teeth with tiny inner cusp.

External appearance (Figs 3C, 5B). Animal with reticulated skin, pale creamy grey to greyish body. Five well-developed mantle extensions same colour as body; right shell lobe (rsl) larger and longer than left shell lobe (lsl); right dorsal lobe (rdl) larger than both anterior left dorsal lobe (ant-ldl) and posterior left dorsal lobe (post-ldl). Sole divided into three parts longitudinally. Caudal foss and caudal horn present.

Figure 5. 

Living snails of Burmochlamys species A B. fasciola sp. nov. paratype CUMZ 14214 showing left and right lateral views B B. cassidula specimen CUMZ 14209 C B. poongee specimen CUMZ 14210 D B. albida sp. nov. paratype CUMZ 14212 E B. moulmeinica sp. nov. paratype CUMZ 14217 F B. versicolor sp. nov. paratype CUMZ 14219 G B. whitteni sp. nov. paratype CUMZ 14222.

Distribution

Burmochlamys cassidula is known only from Kaw Gon Cave in Myanmar (Fig. 1). The isolated limestone outcrop is surrounded by paddy fields and temporary wetlands (flooded in the monsoon season). We searched after rain and found them on the surface of limestone walls. The carnivorous snail Haploptychius sp. was also found sympatrically at this locality (Fig. 4D).

Remarks

Burmochlamys cassidula is easy to distinguish from all other recognised congeners by its unique shell colour pattern: milky-white with a yellow tinge and with one wide yellowish brown peripheral band.

Burmochlamys cauisa (Benson, 1859), comb. nov.

Fig. 6C

Helix cauisa Benson, 1859: 388. Type locality: Phie Than, vallis Tenasserim [Phie Than, Tenasserim Valley].

Helix causia [sic] — Pfeiffer, 1868: 118; Hanley and Theobald 1874: 37, pl. 90, figs 2, 3; Tryon 1887: 102, pl. 15, figs 67, 68.

Macrochlamys causia [sic] — Godwin-Austen, 1907: 163; Blanford and Godwin-Austen 1908: 117.

Macrochlamys cauisa — Pholyotha et al. 2020b: 186, 187, fig. 3a.

Material examined

Type material. Tenasserim: probable syntypes UMZC I.102465.

Other material

Kalryenmullay Hills, Tenasserim: NHMUK 1888.12.4.465–466 ex. Blanford Coll. (two shells; Fig. 6C; specimen figured in Pholyotha et al. 2020b: fig. 3a).

Remarks

Shell morphology of B. cauisa is matched well to this new genus rather than the depressed and lustrous shell of the Macrochlamys (see Pholyotha et al. 2020b). The unique shell morphology is subglobose, small size (width of ~ 7.0 mm, height of ~ 4.0 mm), obliquely striated and very minutely longitudinal lines, moderately elevated spire, enlarged and well-rounded last whorl, ovate lunate aperture, simple peristome, simple columellar margin with slightly reflected near umbilicus, and narrowly open umbilicus (Fig. 6C; Benson 1859; Blanford and Godwin-Austen 1908). Unfortunately, we could not find any specimens identifiable to this species during this survey.

Figure 6. 

Shells of Burmochlamys species A, B B. cassidula specimen CUMZ 14209 C B. cauisa specimen NHMUK 1888.12.4.465-466 D B. perpaula specimen NHMUK 1903.7.1.533 E, F B. poongee E specimen NHMUK 1888.12.4.23-6 F specimen CUMZ 14210.

Burmochlamys cauisa is currently known only from the type locality and vicinity of Salween River basin (Blanford and Godwin-Austen 1908). It is easy to distinguish from all other congeners by its moderately elevated spire and rather broad ovate lunate aperture. In comparison, most species of Burmochlamys gen. nov. have a higher shell spire and narrower aperture opening.

Burmochlamys perpaula (Benson, 1859), comb. nov.

Fig. 6D

Helix perpaula Benson, 1859: 390. Type locality: Phie Thán, raro [Phie Than, Tenasserim Valley].

Helix perpaula — Pfeiffer, 1868: 69.

Nanina (Macrochlamys) perpaula — Tryon, 1886: 89, pl. 29, fig. 37.

Macrochlamys perpaula — Godwin-Austen, 1883: 89, pl. 14, fig. 5; Blanford and Godwin-Austen 1908: 123; Pholyotha et al. 2020b: 187, 188, fig. 3b.

Material examined

Type material. The type series could not be located.

Other material

Moulmein: NHMUK 1903.7.1.533 ex. Godwin-Austen Coll. (one shell; Fig. 6D; specimen figured in Godwin-Austen 1883: pl. 14, fig. 5 and Pholyotha et al. 2020b: fig. 3b), NHMUK ex. MacAndrew Coll. Acc. No. 1563 (six shells), NHMUK 1912.4.16.400 (three shells).

Remarks

Burmochlamys perpaula is currently known only from the type locality in Tenasserim Valley (Benson 1859; Blanford and Godwin-Austen 1908). The original type series could not be located, and no specimens were found in this study. Therefore, the generic placement is still provisional and awaiting for further anatomical information. However, Helix perpaula is transferred to this new genus, which it distinct from the Macrochlamys by a numbers of shell morphology (see Pholyotha et al. 2020b).

Burmochlamys perpaula is characterised by subglobose, small size (width of ~ 2.0 mm, height of ~ 1.3 mm), obliquely striated and very minutely spirally ribbed throughout, moderately elevated spire, rather more convex body whorl, and narrowly crescent-shaped aperture, simple peristome, simple columellar margin with slightly reflected near umbilicus, and narrowly open umbilicus (Fig. 6D; Benson 1859; Blanford and Godwin-Austen 1908). In addition, this species can be distinguished from all other congeners by its moderately elevated spire, rather more convex body whorl, and narrower umbilicus. In comparison, most species of Burmochlamys gen. nov. have a higher shell spire, rather broad and well-rounded last whorl, and relatively wider umbilicus.

Burmochlamys poongee (Theobald, 1859), comb. nov.

Figs 1, 2B, 3B, 5C, 6E, F, 8D–F, 9B, 11B

Helix poongee Theobald, 1859: 307. Type locality: prope Moulmein [Mawlamyine, Mon State, Myanmar].

Helix poongee — Pfeiffer, 1868: 134; Hanley and Theobald 1876: 8, pl. 16, fig. 9.

Helix poongi Theobald, 1876: 19 [incorrect subsequent spelling].

Macrochlamys poongee — Godwin-Austen, 1882: 90, pl.14, fig. 1; Pholyotha et al. 2020b: 190, 191, figs 3e, 3f.

Nanina poongee — Tryon, 1886: 98, pl. 33, fig. 70.

Macrochlamys pungi — Blanford and Godwin-Austen, 1908: 122. [unjustified emendation; ICZN 1999: Art.19.1 and 33.2.3].

Material examined

Type material. The type series could not be located.

Other material

Moulmein: NHMUK 1869.06.1.1 ex. Blanford Coll. (one shell; specimen figured in Pholyotha et al. 2020b: fig. 3e), NHMUK 1888.12.4.23–26 ex. Blanford Coll. (four shells; Fig. 6E; specimen figured in Pholyotha et al. 2020b: fig. 3f), NHMUK ex. Blanford Coll. (two shells). Kaw Ka Thaung Cave, Hpa-An, Kayin State, Myanmar (16°49'42.0"N, 97°42'22.9"E): CUMZ 14210 (Fig. 6F).

Diagnosis

Shell globose and pale to dark brownish. Animal pale to dark greyish with a brown or yellow tinge and five mantle extensions. Genitalia with slender epiphallus, rather short epiphallic caecum attached by a thin penial retractor muscle, and very long and slender at the base of dart apparatus.

Description

Shell (Figs 6E, F, 8D–F). Shell globose, small (width up to 6.5 mm, height up to 5.2 mm), rather thin, semi-translucent. Colour pale to dark brownish. Protoconch and teleoconch surface with similar sculpture. Surface of body whorl with distinct spiral furrows at regular intervals, crossed by distinctly undulating radial lines (Fig. 8D–F). Whorls 6–7, increasing regularly; suture shallowly impressed; spire much elevated; last whorl well-rounded. Aperture obliquely crescent-shaped; peristome simple. Columellar margin simple, slightly reflected near umbilicus. Umbilicus open, narrow, and deep.

Genital organs (Fig. 9B). Atrium (at) rather short. Penis (p) moderate, cylindrical, and with a penial sheath. Epiphallus (e1+e2), slender, ca. four-fifths of penis length; e1 cylindrical and its diameter smaller than penis and e2; e2 bulbous and ca. one-third of e1 length. Epiphallic caecum (ec) rather short, cylindrical, and with a thin penial retractor muscle (prm) attached at tip. Vas deferens (vd) thin tube. Dart apparatus large, very long cylindrical with at the base very long, small, convoluted, and located on atrium near genital orifice. Vagina (v) rather short, and cylindrical. Gametolytic sac (gs) bulbous; gametolytic duct (gd) cylindrical, moderate, ca. three-fifths of penis length. Free oviduct (fo) ca. three-fifths of penis length, cylindrical, and encircled with thick tissue near vagina.

Radula (Fig. 11B). Resembles B. cassidula. Teeth arranged in wide U-shaped rows with each row consisting of ~ 60 teeth. Central tooth monocuspid, large and ovate spatulate shape; with two smaller triangular-shaped plates. Laterals and marginals not differentiated, monocuspid, large spatulate shape and then gradually become narrower, elongate, and rather more pointed cusps, and with one smaller triangular-shaped plate at base. Some outermost teeth with small and pointed cusp at inner side.

External appearance (Fig. 3B, 5C). Living animal with reticulated skin, pale to dark greyish with a brown or yellow tinge, slightly lighter on foot sole and darker colour on caudal horn. Mantle extension well developed with three dorsal lobes and two shell lobes, similar colour to body.

Distribution

Burmochlamys poongee can be found only from Kaw Ka Thaung Cave in Myanmar (Figs 1, 2B). This limestone is surrounded by paddy fields which are temporarily flooded during the monsoon season (Fig. 2B).

Burmochlamys albida Pholyotha & Panha, sp. nov.

https://zoobank.org/CF80F28E-FFF3-4C4E-A453-D383CA8FA1E2
Figs 1, 2C, 5D, 7A, B, 8G–I, 9C, 11C

Material examined

Type material. Holotype: CUMZ 14211 (Fig. 7A; width 4.5 mm, height 3.7 mm). Paratypes: Same locality as holotype: CUMZ 14212 (Fig. 7B; width 4.4 mm, height 3.2 mm), NHMUK (two shells).

Figure 7. 

Shells of Burmochlamys species A, B B. albida sp. nov. A holotype CUMZ 14211, and D paratype CUMZ 14212 C, D B. fasciola sp. nov. C holotype CUMZ 14213 D paratype CUMZ 14214 E, F B. moulmeinica sp. nov. E holotype CUMZ 14216 F paratype CUMZ 14217.

Type locality

Limestone outcrop at Waiponla Monastery, Hpa-An, Kayin State, Myanmar (16°56'07.4"N, 97°42'56.8"E).

Diagnosis

Shell globose and milky-white with a yellow tinge, rarely with a faintly yellowish brown peripheral band. Animal pale fleshy grey with brown or yellow tinge and five mantle extensions. Genitalia with rather short epiphallic caecum attached by a very large and thick penial retractor muscle and rather short vagina.

Description

Shell (Figs 7A, B, 8G–I). Shell globose, small (width up to 4.5 mm, height up to 3.7 mm), thin, semi-translucent. Colour milky-white with a yellow tinge and without or rarely with faintly yellowish brown band above periphery. Protoconch and teleoconch surface with similar sculpture. Surface of body whorl with little distinct spiral furrows at regular intervals, crossed by very faintly undulating radial lines (Fig. 8G–I). Whorls 6–6½, increasing regularly; suture shallowly impressed; spire much elevated; last whorl well-rounded. Aperture obliquely crescent-shaped; peristome simple. Columellar margin simple, slightly reflected near umbilicus. Umbilicus open, narrow, and deep.

Genital organs (Fig. 9C). Atrium (at) rather short. Penis (p) moderate, cylindrical, and with penial sheath covering more than half of its length. Epiphallus (e1+e2) ca. three-sevenths of penis length; e1 cylindrical and small diameter smaller than penis and e2; e2 bulbous and ca. half of e1 length. Epiphallic caecum (ec) rather short, cylindrical, and with very large and thick penial retractor muscle (prm) attached at tip. Vas deferens (vd) thin tube. Dart apparatus large, long cylindrical, and located on atrium close to genital orifice. Vagina (v) rather short, cylindrical-shaped. Gametolytic sac (gs) bulbous; gametolytic duct (gd) cylindrical, moderate, ca. half of penis length. Free oviduct (fo) ca. one-quarter of penis length, cylindrical, and encircled with thick tissue near vagina.

Radula (Fig. 11C). Generally resembles B. cassidula. Teeth arranged in wide U-shaped rows, each row consisting of ~ 55 teeth. Central tooth monocuspid, large, and ovate spatulate shape; with two smaller triangular-shaped teeth. Laterals and marginals not differentiated, monocuspid, large spatulate shape and then gradually become narrower, elongate, rather more pointed cusp, and with one smaller triangular-shaped tooth. Some outermost teeth with a small, pointed cusp at the inner side.

External appearance (Fig. 5D). Living animal with reticulated skin, pale freshy-grey with a brown or yellow tinge. Five well-developed mantle extensions, with similar colour to body. Sole divided into three parts longitudinally; caudal foss and caudal horn well developed, similar colour to body.

Etymology

The specific epithet albida is from the Latin word albidus meaning white. It refers to the whitish shell, which characterises this species.

Distribution

Burmochlamys albida sp. nov. is endemic to a limestone outcrop at Waiponla Monastery. The surrounding paddy fields usually become flooded during the monsoon season (Figs 1, 2C). In addition, this new species is also sympatric with the limestone karst-restricted species, Sophina salweenica Sutcharit & Panha, 2020.

Remarks

Among the whitish-shelled species (see Table 2), B. albida sp. nov. has a very indistinctly narrow yellowish brown peripheral band, whereas B. cassidula has a wide yellowish brown peripheral band, B. fasciola sp. nov. has a narrow yellowish brown peripheral band, and B. versicolor sp. nov. has yellowish brown body whorl near the aperture and wider umbilicus than the other preceding species. Anatomically, B. albida sp. nov. has a large and thick penial retractor muscle, rather slender vagina, and simple at the tip of dart apparatus. In comparison, B. cassidula has a thin penial retractor muscle, large and short vagina, and soft at the tip of dart apparatus, while B. fasciola sp. nov. has a thin penial retractor muscle, very short vagina, and solid at the tip of dart apparatus. In addition, B. versicolor sp. nov. has a thin penial retractor muscle, rather slender vagina, and relatively smaller dart apparatus with soft at the tip.

Burmochlamys albida sp. nov. differs from the remaining Burmochlamys species by having a milky-white shell. While most other species have a pale to dark brownish shell without a peripheral band (see Table 2). Regardless of the shell colour and genitalia, this new species differs from B. cauisa and B. perpaula by spire, body whorl, and aperture. In comparison, B. cauisa has slightly elevated spire, well-rounded last whorl, and rather broad crescent-shaped aperture, while B. perpaula has slightly elevated spire, rather more convex body whorl, and narrower crescent-shaped aperture.

Burmochlamys fasciola Pholyotha & Panha, sp. nov.

https://zoobank.org/BDE9EEDE-1DAC-418E-9097-1EDCC579299B
Figs 1, 2A, 3A, 5A, 7C, D, 8J–L, 10A, 11D

Material examined

Type material. Holotype: CUMZ 14213 (Fig. 7C; width 5.6 mm, height 5.1 mm). Paratypes: Same locality as holotype: CUMZ 14214 (Fig. 7D; width 5.8 mm, height 4.9 mm), NHMUK (two shells).

Other material

Kyankaw Mountain, Hpa-An, Kayin State, Myanmar (17°00'59.5"N, 97°42'12.4"E): CUMZ 14215.

Type locality

Bardai Mountain, Hpa-An, Kayin State, Myanmar (17°00'00.5"N, 97°41'41.6"E).

Diagnosis

Shell globose and milky white with narrow yellowish brown band. Animal pale freshy-grey with five mantle extensions. Genitalia with rather short epiphallic caecum attached by thin penial retractor muscle, very short vagina, and solid at the tip of dart apparatus.

Description

Shell (Figs 7C, D, 8J–L). Shell globose, small (width up to 6.1 mm, height up to 6.0 mm), thin, semi-translucent. Colour milky-white with a narrow yellowish brown band above periphery. Protoconch and teleoconch surface with similar sculpture. Surface of body whorl with distinct spiral furrows at regular intervals, cut by distinctly undulating radial lines (Fig. 8J–L). Whorls 6–6½, increasing regularly; suture shallowly impressed; spire much elevated; last whorl well-rounded. Aperture obliquely crescent-shaped; peristome simple. Columellar margin simple, slightly reflected near umbilicus. Umbilicus open, narrow, and deep.

Figure 8. 

Representative SEM images of the shell of Burmochlamys species A–C B. cassidula specimen CUMZ 14209 A protoconch B body whorl C zoom-in view of body whorl D–F B. poongee specimen CUMZ 14210 D protoconch E body whorl F zoom-in view of body whorl G–I B. albida sp. nov. paratype CUMZ 14212 G protoconch H body whorl I zoom-in view of body whorl J–L B. fasciola sp. nov. paratype CUMZ 14214 J protoconch K body whorl L zoom-in view of body whorl.

Genital organs (Fig. 10A). Atrium (at) very short or indistinct. Penis (p) moderate, cylindrical and with a thin penial sheath. Epiphallus (e1+e2) ca. three-fifths of penis length; e1 cylindrical and smaller diameter than penis and e2; e2 bulbous and ca. half of e1 length. Epiphallic caecum (ec) rather short, cylindrical and with a thin penial retractor muscle (prm) attached at tip. Vas deferens (vd) thin tube. Dart apparatus large, long cylindrical, with solid at the tip (yellow arrow in Fig. 10A), and located on atrium at vagina and penis junction. Vagina (v) very short to indistinguishable. Gametolytic sac (gs) bulbous; gametolytic duct (gd) cylindrical, moderate, slightly shorter than penis. Free oviduct (fo) ca. half of penis length, cylindrical, and encircled with thick tissue near vagina.

Radula (Fig. 11D). Teeth arranged in wide U-shaped rows with each row consisting of ~ 50 teeth. Central tooth monocuspid, large and oblong spatulate plate, and attached by two smaller triangular-shaped teeth at its base. Laterals and marginals not differentiated and monocuspid; each tooth with large and oblong spatulate plate attached by only a smaller triangular-shaped tooth at base on outer side. From inner to outer, lateromarginal teeth gradually narrower, smaller, and rather more pointed cusp. Some outermost teeth with a small and pointed cusp at inner side.

Figure 9. 

General view of the genital system of Burmochlamys species A B. cassidula specimen CUMZ 14209 B B. poongee specimen CUMZ 14210 C B. albida sp. nov. paratype CUMZ 14212. White arrow indicates the end of the penis. Red-dotted line indicates vas deferens missing.

External appearance (Figs 3A, 5A). Living animal with reticulated skin and pale freshy-grey body. Five mantle extensions present, same colour as body. Sole divided into three parts longitudinally. Caudal foss (cf) and caudal horn (ch) present with similar colour to body.

Etymology

The specific epithet is the Latin word fasciola meaning band or stripe. It refers to the presence of a brownish peripheral band, which characterises this species.

Distribution

Burmochlamys fasciola sp. nov. is known from two limestone areas in the south of the Salween River basin (Fig. 1). The Bardai Mountain (Fig. 2A) and Kyankaw Mountain are surrounded by paddy fields that are temporarily flooded during the monsoon season. In Kyankaw Mountain, this new species is sympatric with the limestone karst-restricted land snail species, salweenica.

Remarks

The distinguishing characters of B. fasciola sp. nov. is a milky-white shell with a narrow yellowish brown peripheral band and rather elongated radular teeth. Whereas the other Burmochlamys species have a pale to dark brownish shell without any band and the radular teeth have a broad spatulate shape (see Table 2).

Table 2.
Download as
CSV
XLSX

Comparison of shell, radula, genital system, and distribution of all members of Burmochlamys gen. nov. in Myanmar.

B. cassidula B. cauisa* B. perpaula* B. poongee B. albida sp. nov. B. fasciola sp. nov. B. moulmeinica sp. nov. B. versicolor sp. nov. B. whitteni sp. nov.
shell colour whitish with a yellow tinge pale yellowish brown dark brown pale to dark brown whitish with a yellow tinge whitish pale to dark brown whitish yellow / yellowish brown pale to dark brown
peripheral band wide absent absent absent absent or rarely indistinct narrow absent absent absent
shell shape globose subglobose subglobose globose globose globose globose subglobose globose
microscopic sculpture present present present present present present present present but indistinct present
umbilicus narrow narrow very narrow narrow narrow narrow narrow moderate narrow
central tooth shape broad spatulate – – broad spatulate broad spatulate narrow spatulate broad spatulate narrow spatulate broad spatulate
penis rather short moderate moderate moderate moderate moderate rather long
penial retractor muscle thin – – thin thick thin thin thin thick
vagina very short – – short short very short short short very short
the tissue surrounding gametolytic part and free oviduct absent – – absent absent absent absent absent present
dart apparatus near atrium rather long – – very long rather long rather short rather short rather short rather long
at the tip of dart apparatus soft – – soft soft solid soft soft soft

*Information from Blanford and Godwin-Austen (1908).

Burmochlamys moulmeinica Pholyotha & Panha, sp. nov.

https://zoobank.org/E00C82AB-384E-408D-AEBC-F011AA9C2DD7
Figs 1, 2D, 4A, 5E, 7E, F, 10B, 13A–C, 15A

Material examined

Type material. Holotype: CUMZ 14216 (Fig. 7E; width 5.0 mm, height 4.2 mm). Paratypes: Same locality as holotype: CUMZ 14217 (Fig. 7F; width 4.5 mm, height 4.2 mm), NHMUK (two shells).

Type locality

Limestone outcrop at Lun Nya Pagoda, Hpa-An, Kayin State, Myanmar (16°44'53.8"N, 97°47'09.1"E).

Diagnosis

Shell globose and pale to dark brownish. Animal greyish with five mantle extensions. Genitalia with very short epiphallic caecum attached by a thin penial retractor muscle and rather short vagina.

Description

Shell (Figs 7E, F, 13A–C). Shell globose, small (width up to 5.0 mm, height up to 4.2 mm), rather thin, and semi-translucent. Colour pale to dark brownish. Protoconch and teleoconch surface with similar sculpture. Surface of body whorl with distinct spiral furrows at regular intervals, cut by distinctly undulating radial lines (Fig. 13A–C). Whorls 6–6½, increasing regularly; suture shallowly impressed; spire much elevated; last whorl well-rounded. Aperture obliquely crescent-shaped; peristome simple. Columellar margin simple, slightly reflected near umbilicus. Umbilicus open, narrow, and deep.

Genital organs (Fig. 10B). Atrium (at) very short. Penis (p) moderate, cylindrical and with thin penial sheath. Epiphallus (e1+e2) ca. half of penis length; e1 cylindrical and smaller diameter smaller than penis and e2; e2 bulbous and ca. half of e1 length. Epiphallic caecum (ec) very short, bulbous, and with thin penial retractor muscle (prm) attached at tip. Vas deferens (vd) thin tube. Dart apparatus large, long cylindrical, and located on atrium at vagina and penis junction. Vagina (v) rather short, cylindrical. Gametolytic sac (gs) bulbous; gametolytic duct (gd) cylindrical, rather short, ca. half of penis length. Free oviduct (fo) ca. two-third of penis length, cylindrical, and encircled with thick tissue near vagina.

Figure 10. 

General view of the genital system of Burmochlamys species A B. fasciola sp. nov. paratype CUMZ 14214 B B. moulmeinica sp. nov. paratype CUMZ 14217 C B. versicolor sp. nov. paratype CUMZ 14219. White arrow indicates the end of the penis. Yellow arrow indicates the solid at the tip of dart apparatus. Red-dotted line indicates vas deferens missing.

Radula (Fig. 15A). Resembles B. cassidula. Teeth arranged in wide U-shaped rows with each row consisting of ~ 50 teeth; central tooth monocuspid, large and ovate spatulate shape with both sides of its base attached by two triangular-shaped plates; laterals and marginals not differentiated, monocuspid, large spatulate shape then gradually become narrower, elongate, smaller, and rather more pointed cups outwards, and attached at base and on outer side by one smaller triangular-shaped plate.

External appearance (Figs 4A, 5E). Living animal with reticulated skin, grey body, slightly lighter on foot sole and darker colour on caudal horn. Mantle extensions with three dorsal lobes and two shell lobes; same colour as body.

Etymology

The specific epithet moulmeinica is a noun in reference to the historical name of Mawlamyine city, pertaining to the Salween River basin, where the type locality is situated.

Distribution

Burmochlamys moulmeinica sp. nov. is endemic to a small limestone area at Lun Nya Pagoda in Myanmar (Figs 1, 2D). The isolated limestone is surrounded by paddy fields that are temporarily flooded during the monsoon season (Fig. 2D). In addition, this new species is also sympatric with the limestone karst-restricted species, Sophina pisinna Sutcharit & Panha, 2020.

Remarks

Burmochlamys moulmeinica sp. nov. is similar to B. poongee in shell morphology but can be differentiated by genitalia. This new species has a relatively short epiphallus and a rather short at the base of dart apparatus, whereas B. poongee has a slender and longer epiphallus and a very long and small at the base of dart apparatus.

Burmochlamys versicolor Pholyotha & Panha, sp. nov.

https://zoobank.org/096635E4-809B-437B-BE16-197FD4D38D1B
Figs 1, 2E, 4B, C, 5F, 10C, 12A, B, 13D–F, 15B

Material examined

Type material. Holotype: CUMZ 14218 (Fig. 12A; width 6.0 mm, height 4.2 mm). Paratypes: Same locality as holotype: CUMZ 14219 (Fig. 12B; width 5.9 mm, height 4.5 mm), NHMUK (two shells).

Figure 11. 

Representative SEM images of the radula of Burmochlamys species A B. cassidula specimen CUMZ 14209 B B. poongee specimen CUMZ 14210 C B. albida sp. nov. paratype CUMZ 14212 D B. fasciola sp. nov. paratype CUMZ 14214. Central tooth indicated by ‘C’; yellow colour indicates central tooth row.

Other material

Limestone outcrop at Golden valley, Hpa-An, Kayin State, Myanmar (16°51'02.3"N, 97°36'26.1"E): CUMZ 14220.

Type locality

Limestone outcrop at Bayin Nyi Cave, Hpa-An, Kayin State, Myanmar (16°58'10.1"N, 97°29'30.6"E).

Diagnosis

Shell subglobose, whitish yellow and then gradually turned yellowish brown near aperture opening, and umbilicus somewhat narrow and very deep. Animal dark greyish with five mantle extensions. Genitalia with very short epiphallic caecum attached by thin penial retractor muscle, rather short vagina, and small, slender, rather short gametolytic duct.

Description

Shell (Figs 12A, B, 13D–F). Shell subglobose, small (width up to 6.3 mm, height up to 4.9 mm), thin, semi-translucent. Colour whitish yellow and then gradually turned yellowish brown on body whorl near aperture opening. Protoconch and teleoconch surface with similar sculpture. Surface of body whorl with indistinct spiral furrows without radial lines (Fig. 13D–F). Whorls 5½–6, increasing regularly; suture shallowly impressed; spire rather elevated; last whorl broad and well-rounded. Aperture obliquely crescent-shaped; peristome simple. Columellar margin simple, slightly reflected near umbilicus. Umbilicus open, moderate, and very deep that show preceding whorl.

Figure 12. 

Shells of Burmochlamys species A, B B. versicolor sp. nov. A holotype CUMZ 14218, and D paratype CUMZ 14219 C, D B. whitteni sp. nov. C holotype CUMZ 14221, and D paratype CUMZ 14222.

Genital organs (Fig. 10C). Atrium (at) very short. Penis (p) moderate, cylindrical and with penial sheath. Epiphallus (e1+e2) ca. one-third of penis length; e1 cylindrical and its slightly smaller diameter than penis and e2; e2 bulbous and slightly longer than e1. Epiphallic caecum (ec) very short, small, bulbous with thin penial retractor muscle (prm) attached at tip. Vas deferens (vd) thin tube. Dart apparatus rather small, long cylindrical, and located on atrium at vagina and penis junction. Vagina (v) rather short and cylindrical. Gametolytic sac (gs) rather large, elongate bulbous; gametolytic duct (gd) small, slender, and rather short ca. half of penis length. Free oviduct (fo) cylindrical, very long ca. half of penis length, and encircled with thick tissue near vagina.

Radula (Fig. 15B). Teeth arranged in wide U-shaped rows, each row consisting of ~ 40 teeth. Central tooth monocuspid, large and oblong spatulate plate, and attached at both sides of its base by two smaller triangular-shaped teeth. Laterals and marginals not differentiated and monocuspid; each tooth with large and oblong spatulate plate attached by one smaller triangular-shaped tooth on outer side of its base. Outermost teeth shorter and smaller than inner teeth.

External appearance (Figs 4B, 5F). Living animal with reticulated skin and pale to dark greyish body. Mantle extensions well developed, divided to three dorsal lobes and two shell lobes; same colour as body. Foot margin and caudal horn well-developed, dark greyish.

Etymology

The specific epithet is the Latin word versicolor meaning of various colours. It refers to the two distinct shell colours which characterise this species.

Distribution

Burmochlamys versicolor sp. nov. is confirmed from two localities in the south of Salween River basin (Fig. 1). Bayin Nyi Cave is surrounded by paddy fields that are temporarily flooded during the monsoon season (Fig. 2E), while Golden valley is a small limestone outcrop located close to the Thanlwin River (= Salween River). Occurrence of the new species between the two limestone areas is expected. A living snail was found climbing up a limestone wall and many mating pairs were also discovered at Bayin Nyi Cave (Fig. 4B), where the carnivorous snail Carinartemis sp. was also found sympatrically (Fig. 4C).

Remarks

Burmochlamys versicolor sp. nov. is easy to distinguish from all known species by having (i) a whitish yellow shell with yellowish brown colour on ca. one-fourth of body whorl near the aperture, (ii) shell sculpture as only shallow spiral lines, and (iii) much wider and larger umbilicus that shows the preceding whorl. In comparison, all other congeneric species have (i) a brownish or whitish shell colour, with or without peripheral band, (ii) a shell surface with both impressed spiral lines and undulating radial lines, and (iii) a small umbilicus (see Table 2).

Burmochlamys whitteni Pholyotha & Panha, sp. nov.

https://zoobank.org/3F800E38-AB3F-4185-9871-CA7DA26456A2
Figs 1, 5G, 12C, D, 13G–I, 14, 15C

Material examined

Type material. Holotype: CUMZ 14221 (Fig. 12C; width 5.8 mm, height 5.0 mm). Paratypes: Same locality as holotype: CUMZ 14222 (Fig. 12D; width 5.6 mm, height 5.0 mm), NHMUK (two shells).

Type locality

Limestone outcrop at Htaung Wee Cave, Hpa-An, Kayin State, Myanmar (16°50'31.1"N, 97°37'18.4"E).

Diagnosis

Shell globose and pale to dark brownish. Animal pale grey with five mantle extensions. Genitalia with slender epiphallus, rather short epiphallic caecum attached by a thick and short penial retractor muscle, and gametolytic part and free oviduct entirely encircled by connective tissue.

Description

Shell (Figs 12C, D, 13G–I). Shell globose, small (width up to 5.8 mm, height up to 5.0 mm), rather thin, and semi-translucent. Colour pale to dark brownish. Protoconch and teleoconch surface with similar sculpture. Surface of body whorl with distinct spiral furrows at regular intervals, cut by undulating radial lines (Fig. 13G–I). Whorls 6–6½, increasing regularly; suture shallowly impressed; spire much elevated; last whorl well-rounded. Aperture obliquely crescent-shaped; peristome simple. Columellar margin simple, slightly reflected near umbilicus. Umbilicus open, narrow, and deep.

Figure 13. 

Representative SEM images of the shell of Burmochlamys species A–C B. moulmeinica sp. nov. paratype CUMZ 14217 A protoconch B body whorl C zoom-in view of body whorl. D–F B. versicolor sp. nov. paratype CUMZ 14219 D protoconch E body whorl F zoom-in view of body whorl G–I B. whitteni sp. nov. paratype CUMZ 14222 G protoconch H body whorl I zoom-in view of body whorl.

Genital organs (Fig. 14). Atrium (at) short. Penis (p) rather long, cylindrical and with penial sheath. Epiphallus (e1+e2) ca. five-eighths of penis length; e1 cylindrical and smaller diameter than penis and e2; e2 bulbous and ca. two-third of e1 length. Epiphallic caecum (ec) rather short, cylindrical, and with thick and short penial retractor muscle (prm) attached at tip. Vas deferens (vd) thin tube. Dart apparatus large, long cylindrical, and located on atrium at vagina and penis junction. Vagina (v) very short and cylindrical. Gametolytic sac (gs) bulbous; gametolytic duct (gd) cylindrical, moderate, ca. three-eighths of penis length; thin connective tissue encircled entire gametolytic organ and free oviduct (Fig. 14A, B). Free oviduct (fo) as long as gametolytic duct.

Figure 14. 

Genital system of Burmochlamys whitteni sp. nov. paratype CUMZ 14222 A general view of the genital system B a part of gametolytic organ (duct and sac) and free oviduct after the connective tissue is removed. White arrow indicates the end of the penis. Yellow arrow indicates the connective tissue surrounding the gametolytic organ and free oviduct.

Radula (Fig. 15C). Resembles B. cassidula. Teeth arranged in wide U-shaped rows with each row consisting of ~ 55 teeth; central tooth monocuspid, large and ovate spatulate shape and attached at both sides of its base with two smaller triangular-shaped plates; lateromarginals monocuspid, large and ovate spatulate shape and then gradually smaller, narrower, and rather more pointed cusp; each lateromarginal tooth with one smaller triangular-shaped plate attached at base outwards. Some outermost teeth with a small and pointed cusp at inner side.

Figure 15. 

Representative SEM images of the radula of Burmochlamys species A B. moulmeinica sp. nov. paratype CUMZ 14217 B B. versicolor sp. nov. paratype CUMZ 14219 C B. whitteni sp. nov. paratype CUMZ 14222. Central tooth indicated by ‘C’; yellow colour indicates central tooth row.

External appearance (Fig. 5G). Living animal with reticulated skin, pale grey body, slightly paler on foot sole and darker colour on caudal horn. Mantle extensions with two shell lobes and three dorsal lobes, similar colour to body.

Etymology

The specific epithet whitteni is named in honour of the late Dr. Tony Whitten (1957–2017) of Fauna & Flora International, who invited our team to explore the land snails in southern Myanmar during 2015 to 2016.

Distribution

Burmochlamys whitteni sp. nov. is known only from the type locality (Fig. 1). This isolated limestone of Htaung Wee Cave is situated close to the east-bank of the Thanlwin River and is surrounded by paddy fields that are temporarily flooded during the monsoon season.

Remarks

Among the brownish-shelled species (see Table 2), B. whitteni sp. nov. can be distinguished from B. poongee and B. moulmeinica sp. nov. by the presence of the connective tissue encircled entirely at the gametolytic part and free oviduct, whereas in the latter two species this tissue is absent. In addition, B. whitteni sp. nov. has a thick penial retractor muscle, relatively long epiphallus, and rather short at the base of dart apparatus. In contrast, B. poongee has a thin penial retractor muscle, relatively long epiphallus, and very long at the base of dart apparatus, while B. moulmeinica sp. nov. has a thin penial retractor muscle, relatively short epiphallus, and rather short at the base of dart apparatus.

Discussion

Taxonomic implications from morphological and anatomical studies

With regard to the lack of synapomorphies, the delimitation of the Helicarionidae is vague and the relationship within this family is still far from resolved (Hausdorf 1998; Hyman and Ponder 2010). Hausdorf (1998) stated that only the Durgellinae Godwin-Austen, 1888 can be substantiated as a monophyly and are characterised by the reduced flagellum and large shell lobes (apparently secondarily reduced in Sitala). At present the only limacoid groups that possess monocuspid radula with spatulate shape are Aenigmatoconcha and Sophina, placed in the Durgellinae (Tumpeesuwan and Tumpeesuwan 2017; Sutcharit et al. 2020; Pholyotha et al. 2021b), and Chalepotaxis, placed in the Helicarionidae (Páll-Gergely et al. 2016). Therefore, we tentatively assign Burmochlamys gen. nov. under the Durgellinae of the Helicarionidae based on the morphological characters outlined above (flagellum reduced, shell lobes possibly secondarily reduced, and monocuspid radula present). Because the higher classification is still provisional, future studies will combine molecular phylogenetic analyses to investigate its true evolutionary position.

Considering only the shell morphology, Burmochlamys gen. nov. is similar to some Southeast Asian genera of the Helicarionidae (i.e., Aenigmatoconcha, Chalepotaxis, Sitala and Sophina) or the Ariophantidae (i.e., Macrochlamys and Microcystina). Among these six genera, Microcystina has the most similar shell to this new genus in having a microscopic shell sculpture and rounded body whorl, but the usual shell shape of Microcystina species is depressed and rarely globosely depressed (Blanford and Godwin-Austen 1908; van Benthem Jutting 1950; Schileyko 2003; Vermeulen et al. 2019), whereas Burmochlamys gen. nov. has a subglobose to globose shell shape. However, most Microcystina species are known only from their shell information and need to be taxonomically revised. Compared with other genera, Burmochlamys gen. nov. can be easily distinguished from Sitala by the shell shape and the body whorl that Sitala has more or less trochiform and subangulated to carinate at the periphery. The presence of the microscopic shell sculpture can be used to separate this new genus from Aenigmatoconcha, Chalepotaxis, Macrochlamys, and Sophina. Shells of the speciose genus Macrochlamys are depressed to globose, smooth, and rounded to angulated at the periphery (Blanford and Godwin-Austen 1908; Pholyotha et al. 2018; Pholyotha et al. 2020b), while Aenigmatoconcha, Chalepotaxis, and Sophina have depressed to globose, smooth, and rounded at the periphery (Páll-Gergely et al. 2016; Sutcharit et al. 2020; Pholyotha et al. 2021b). Despite the similarity of many of the shell traits between Burmochlamys gen. nov. and other genera that has made a lot of taxonomic confusion in the past, the peculiarities of the morphological characters of the mantle extension, radula, and genitalia deserve special consideration (see Table 1).

The noticeable characters of Burmochlamys gen. nov. are the finger-like shell lobe and the spatulate-shaped radula. Previous studies of the anatomy of the Southeast Asian helicarionids and ariophantids noted differences in the mantle morphology (especially the shell lobe), described as a slender or slightly extended shell lobe (i.e., Macrochlamys, Microcystina, and Sitala), or as a broad and enlarged shell lobe (i.e., Aenigmatoconcha, Chalepotaxis, and Sophina). So, the mantle morphology can be used as an informative character to distinguish members of these two families even though reduction of the mantle extension within the same genus has been documented (Blanford and Godwin-Austen 1908; Pholyotha et al. 2020c; Sutcharit and Panha 2021).

With regards to the radular morphology, most genera of helicarionids and ariophantids have a tricuspid central tooth, tricuspid laterals, bicuspid marginals, or undifferentiated lateromarginal teeth with several cusps (Stoliczka 1871; Blanford and Godwin-Austen 1908; van Benthem Jutting 1950; Solem 1966; Schileyko 2002, 2003). While only the Aenigmatoconcha, Chalepotaxis, Sophina, and Burmochlamys gen. nov. have radular teeth with a monocuspid and spatulate shape (Páll-Gergely et al. 2016; Sutcharit et al. 2020; Pholyotha et al. 2021b). The radular morphology of Burmochlamys gen. nov. consists of two types. The large one is spatulate in shape (highlight in yellow and blue colour Fig. 3D, E) and the smaller one is triangular in shape (highlight in red colour Fig. 3D, E). Similarly, Chalepotaxis infantilis (Gredler, 1881) and some species of Sophina (i.e., S. tonywhitteni Sutcharit & Panha, 2020) exhibit this smaller tooth but it is very small (Páll-Gergely et al. 2016; Sutcharit et al. 2020). In contrast, all Aenigmatoconcha species do not have this smaller tooth (Pholyotha et al. 2021b). The same modification of radula that present another smaller tooth located behind the larger tooth is recorded in the arboreal land snails, Amimopina macleayi (Brazier, 1876) and Rhachistia histrio (Pfeiffer, 1855), in the family Cerastidae Wenz, 1923 (Solem 1973). Solem (1973) hypothesised that the functional aspects in the two radular are identical, where the large spatulate tooth scrapes against the food source surface, then another smaller tooth catches and pulls any loose pieces.

Among the genera having the monocuspid radular teeth (Aenigmatoconcha, Burmochlamys gen. nov., Chalepotaxis, and Sophina), the genital organ of this new genus shows a strong similarity to those of Sophina because of the absence of a flagellum and the presence of a straight epiphallic caecum and dart apparatus (Páll-Gergely et al. 2016; Sutcharit et al. 2020; Pholyotha et al. 2021b). In contrast, Aenigmatoconcha has a straight epiphallic caecum and a small flagellum but lacks a dart apparatus (Pholyotha et al. 2021b), while Chalepotaxis has a straight epiphallic caecum but has neither a flagellum nor a dart apparatus (Páll-Gergely et al. 2016).

Regardless of the unique radular teeth of the new genus, the genitalia of Burmochlamys gen. nov. and Microcystina (at least the type species) differ by the epiphallic caecum, which in Burmochlamys gen. nov. is present but Microcystina is absent. Additionally, reduction of dart apparatus in M. bintennensis Godwin-Austen, 1899 (not the type species) is also reported and differs from this new genus (Blanford and Godwin-Austen 1908).

The dart apparatus has chiefly functions during the courtship of the limacoid snails to increase the male reproductive success (Lodi and Koene 2016). With a handful of anatomical information, the dart apparatus has long been used to distinguish genera among the limacoid snails, even though there are some arguments because it seems to have been gained or lost multiple times during snail evolution (Blanford and Godwin-Austen 1908; Hausdorf 1998; Schileyko 2002, 2003; Sutcharit et al. 2020). With regard to the type species, Cryptaustenia Cockerell, 1891, Durgella Blanford, 1863 and Microcystina deserve a special mention because they tend to have a well-developed dart apparatus, but some non-type species classified to these respective genera have no dart apparatus (see Table 1). Likewise, the reversed phenomenon occurs in Sitala, whose type species has no dart apparatus while S. attegia (Benson, 1859) (not the type species) has a well-developed dart apparatus (Table 1). A comprehensive phylogenetic study among these genera has not been published so far, but it would be interesting to know whether the gain or loss of the dart apparatus are facultative or indicate phylogenetic signal.

Geographic distribution of Burmochlamys gen. nov

Although several localities in Shan State, Mon State, Kayin State, and the Tanintharyi Region were surveyed during 2015 and 2016, only some localities of the karst habitat islands in the Salween River basin of Kayin state were found to harbour Burmochlamys gen. nov. where two known and five new species of Burmochlamys gen. nov. were discovered. Thus, a narrow distribution range of the new genus is suggested; however, this is not ascertained because there are several limestone karsts yet to be surveyed in adjacent regions. Interestingly, all species recognised herein (except B. cauisa and B. perpaula which are known only from the type specimen) show high degrees of endemism and localisation (one species per location), which has possibly resulted from the great variety of ecological niches afforded by their complex karst formations and highly fragmented island-like habitat of the Salween River basin (Grismer et al. 2018a, b; Sutcharit et. al. 2020). Similarly, the karst formations of the Mekong Delta Limestones form archipelagos of habitat islands that host an exclusive concentration of endemic land snail taxa along the Vietnamese and Cambodian coast (Vermeulen et al. 2019; Pholyotha et al. 2020a).

Currently restricted to only the Salween River basin (Fig. 1), Burmochlamys gen. nov. and Sophina indeed show high levels of local endemism. Sutcharit et al. (2020) reported that Sophina is genetically divided into two principal groups that are distributed allopatrically on either side of the Gyaing River, and this similar pattern is also documented in geckos at the species-group level (Grismer et al. 2018a, b). Interestingly, all Burmochlamys species show a confined distribution in the north part of the Gyaing River, which possibly implies that the river acts as the geographical barrier and then allopatry and local endemicity play an important role in the diversification of the Burmochlamys species. However, at a few localities, sympatry of Burmochlamys and Sophina species was observed, i.e., Kyankaw Mountain (B. fasciola sp. nov. and S. salweenica), Waiponla Monastery (B. albida sp. nov. and S. salweenica), and Lun Nya Pagoda (B. moulmeinica sp. nov. and S. pisinna). In two sympatric species of Sophina which are distinct in shell size, divergence in body size may reduce interspecific competition and reflect niche partitioning between species (Goodfriend, 1986; Sutcharit et al. 2020). The phenomenon of reducing competition by different body size might possibly also hold for sympatric species of Burmochlamys (shell width about 6.0–8.0 mm) and Sophina (shell width about 9.0–13.0 mm; Sutcharit et al. 2020). However, no molecular phylogenetic analysis of Burmochlamys is available, and so further research on this issue has to reveal how the ecological and evolutionary processes have shaped its diversity patterns.

Acknowledgements

We thank members of the Animal Systematics Research Unit, Chulalongkorn University for assistance in the field and laboratory, and the Fauna & Flora International (FFI) and Ministry of Natural Resources and Environmental Conservation Forest Department, Myanmar for the preparation of permission documents and data collection in Myanmar. We are also grateful to J. Ablett (NHM, London) for allowing the authors to examine the material housed in the type collections, the type material database, and photographs. Special thanks to two reviewers, J. Vermeulen and P. Dumrongrojwattana, for providing valuable comments and suggestions on the manuscript. This project was mainly funded through grants received The Thailand Research Fund (TRF-DPG628001), and Center of Excellence on Biodiversity (BDC-PG2-161002). In addition, this study was supported by the Ratchadapisek Somphot Fund for Postdoctoral Fellowship, Chulalongkorn University to S.P. and A.P.

References

  • Benson WH (1859) New Helicidae collected by W. Theobald, Esq., jun., in Burmah and the Khasia Hills, and described by W.H. Benson. Annals and Magazine of Natural History series 3 3: 387–393.
  • Blanford WT, Godwin-Austen HH (1908) The Fauna of British India, including Ceylon and Burma. Mollusca. Testacellidae and Zonitidae. Taylor and Francis, London, 311 pp. https://doi.org/10.5962/bhl.title.13103
  • Godwin-Austen HH (1882, 1883 [1882–1888]) Land and Freshwater Mollusca of India, Including South Arabia, Baluchistan, Afghanistan, Kashmir, Nepal, Burmah, Pegu, Tenasserim, Malay Peninsula, Ceylon, and other Islands of the Indian Ocean. Supplementary to Messrs. Theobald and Hanley’s Conchologia Indica, Taylor & Francis, London. https://doi.org/10.5962/bhl.title.18138
  • Godwin-Austen HH (1907 [1897–1914]) Land and Freshwater Mollusca of India, Including South Arabia, Baluchistan, Afghanistan, Kashmir, Nepal, Burmah, Pegu, Tenasserim, Malay Peninsula, Ceylon, and other Islands of the Indian Ocean. Supplementary to Messrs. Theobald and Hanley’s Conchologia Indica, Taylor & Francis, London.
  • Godwin-Austen HH (1882–1920) Land and Freshwater Mollusca of India, Including South Arabia, Baluchistan, Afghanistan, Kashmir, Nepal, Burmah, Pegu, Tenasserim, Malay Peninsula, Ceylon, and other Islands of the Indian Ocean. Supplementary to Messrs. Theobald and Hanley’s Conchologia Indica, Taylor & Francis, London. Volumes 1 (pp. 1–257, pls 1–62), Volume 2 (pp. 1–442, pls 63–158) and Volume 3 (pp. 1–65, pls 159–165).
  • Grismer LL, Wood Jr PL, Thura MK, Quah ESH, Murdoch ML, Grismer MS, Herr MW, Lin A, Kyaw H (2018a) Three more new species of Cyrtodactylus (Squamata: Gekkonidae) from the Salween Basin of eastern Myanmar underscore the urgent need for the conservation of karst habitats. Journal of Natural History 52(19–20): 1243–1294. https://doi.org/10.1080/00222933.2018.1449911
  • Grismer LL, Wood Jr PL, Thura MK, Zin T, Quah ESH, Murdoch ML, Grismer MS, Lin A, Kyaw H, Lwin N (2018b) Twelve new species of Cyrtodactylus Gray (Squamata: Gekkonidae) from isolated limestone habitats in east-central and southern Myanmar demonstrate high localized diversity and unprecedented microendemism. Zoological Journal of the Linnean Society 182(4): 862–959. https://doi.org/10.1093/zoolinnean/zlx057
  • Grismer L, Wood Jr PL, Poyarkov NA, Le MD, Karunarathna S, Chomdej S, Suwannapoom C, Qi S, Liu S, Che J, Quah ESH, Kraus F, Oliver PM, Riyanto A, Pauwels OSG, Grismer JL (2021) Karstic Landscapes Are Foci of Species Diversity in the World’s Third-Largest Vertebrate Genus Cyrtodactylus Gray, 1827 (Reptilia: Squamata: Gekkonidae). Diversity 13(5): e183. https://doi.org/10.3390/d13050183
  • Hanley S, Theobald W (1874, 1876 [1870–1876]) Conchologica Indica: Illustrations of the Land and Freshwater Shells of British India. L. Reeve & Co, Covent Garden, London. https://doi.org/10.5962/bhl.title.96210
  • Hyman IT, Köhler F (2018) A revision of eastern Australian land snails placed in Nitor Gude (Helicarionidae, Stylommatophora). Invertebrate Systematics 32(5): 1171–1205. https://doi.org/10.1071/IS18015
  • Hyman IT, Ponder WF (2010) A morphological phylogenetic analysis and generic revision of Australian Helicarionidae (Gastropoda: Pulmonata: Stylommatophora), and an assessment of the relationships of the family. Zootaxa 2462(1): 1–148. https://doi.org/10.11646/zootaxa.2462.1.1
  • Hyman IT, Lamborena I de la I, Köhler F (2017) Molecular phylogenetics and systematic revision of the south-eastern Australian Helicarionidae (Gastropoda, Stylommatophora). Contributions to Zoology 86(1): 51–95. https://doi.org/10.1163/18759866-08601004
  • Lodi M, Koene JM (2016) The love-darts of land snails: Integrating physiology, morphology and behaviour. The Journal of Molluscan Studies 82: 1–10. https://doi.org/10.1093/mollus/eyv046
  • Myers N, Mittermeier RA, Mittermeier CG, da Fonseca GAB, Kent J (2000) Biodiversity hotspots for conservation priorities. Nature 403(6772): 853–858. https://doi.org/10.1038/35002501
  • Páll-Gergely B, Fehér Z, Otani JU, Asami T (2016) An integrative taxonomic approach to infer the systematic position of Chalepotaxis Ancey, 1887 (Gastropoda: Stylommatophora: Helicarionidae). Molluscan Research 37(2): 113–119. https://doi.org/10.1080/13235818.2016.1234996
  • Pfeiffer L (1868) Monographia heliceorum viventium supplementum tertium: sistens descriptions systematicas et criticas omnium hujus familiae generum et specierum hodie cognitarum, volume quintum. F.A. Brockhaus, Lipsiae.
  • Pholyotha A, Sutcharit C, Panha S (2018) The land snail genus Macrochlamys Gray, 1847 from Thailand, with descriptions of five new species (Pulmonata: Ariophantidae). The Raffles Bulletin of Zoology 66: 763–781.
  • Pholyotha A, Sutcharit C, Thach P, Chhuoy S, Ngor PB, Panha S (2020a) Land snail genus Sarika Godwin-Austen, 1907 (Eupulmonata: Ariophantidae) from Cambodia, with description of three new species. European Journal of Taxonomy 674(674): 1–21. https://doi.org/10.5852/ejt.2020.674
  • Pholyotha A, Sutcharit C, Tongkerd P, Lin A, Panha S (2020b) Taxonomic revision of the land snail genera Macrochlamys Gray, 1847 and Sarika Godwin-Austen, 1907 (Eupulmonata: Ariophantidae) from Southeastern Myanmar, with descriptions of three new species. Molluscan Research 40(2): 183–204. https://doi.org/10.1080/13235818.2020.1723041
  • Pholyotha A, Sutcharit C, Tongkerd P, Panha S (2020c) Integrative taxonomic revision of the land snail genus Sarika Godwin-Austen, 1907 in Thailand, with descriptions of nine new species (Eupulmonata, Ariophantidae). ZooKeys 976: 1–100. https://doi.org/10.3897/zookeys.976.53859
  • Pholyotha A, Sutcharit C, Tongkerd P, Jeratthitikul E, Panha S (2021a) Integrative systematics reveals the new land-snail genus Taphrenalla (Eupulmonata: Ariophantidae) with a description of nine new species from Thailand. Contributions to Zoology 90(1): 21–69. https://doi.org/10.1163/18759866-BJA10013
  • Pholyotha A, Sutcharit C, Tongkerd P, Panha S (2021b) Systematic revision of the limestone karst-restricted land snail genus Aenigmatoconcha (Eupulmonata: Helicarionidae), with description of a new species. European Journal of Taxonomy 767: 55–82. https://doi.org/10.5852/ejt.2021.767.1487
  • Schileyko AA (2002) Treatise on recent terrestrial pulmonated mollusks. Part 9. Helicarionidae, Gymnarionidae, Rhysotinidae, Ariophantidae. Ruthenica (Supplement 2): 1167–1307.
  • Schileyko AA (2003) Treatise on recent terrestrial pulmonate molluscs. Part 10. Ariophantidae, Ostracolethidae, Ryssotidae, Milacidae, Dyakiidae, Staffordiidae, Gastrodontidae, Zonitidae, Daudebardiidae, Parmacellidae. Ruthenica (Supplement 2): 1309–1466.
  • Solem A (1966) Some non-marine mollusks from Thailand. Spolia Zoologia Musei Hauniensis 24: 1–110.
  • Solem A (1973) Convergence in Pulmonate radulae. The Veliger 15: 165–171.
  • Stoliczka F (1871) Notes on terrestrial Mollusca from the neighbourhood of Moulmein (Tenasserim provinces), with description of new species. Journal of the Asiatic Society of Bengal 40: 143–177, 217–259.
  • Sutcharit C, Panha S (2021) Systematic review of the dextral Hemiplecta Albers, 1850 (Eupulmonata, Ariophantidae) from Thailand with description of a new species and list of all the Indochinese species. ZooKeys 1047: 101–154. https://doi.org/10.3897/zookeys.1047.65735
  • Sutcharit C, Jeratthitikul E, Pholyotha A, Lin A, Panha S (2020) Molecular phylogeny reveals high diversity and endemism in the limestone karst-restricted land snail genus Sophina Benson, 1859 from Myanmar (Eupulmonata: Helicarionidae), with description of four new species. Journal of Zoological Systematics and Evolutionary Research 58(4): 957–981. https://doi.org/10.1111/jzs.12420
  • Sutcharit C, Jeratthitikul E, Tongkerd P, Panha S (2021) Reassessment and systematic position of the sinistral snails of genus Hemiplecta from Thailand (Eupulmonata: Ariophantidae), with description of two new species. Contributions to Zoology 90(2): 183–215. https://doi.org/10.1163/18759866-BJA10016
  • Tanmuangpak K, Tumpeesuwan C, Tumpeesuwan S (2017) A new species of Sesara Albers, 1860 from northeastern Thailand (Stylommatophora: Helicarionidae). Molluscan Research 37(1): 1–7. https://doi.org/10.1080/13235818.2016.1155431
  • Theobald W (1859) Descriptions of some new Burmese and Indian Helicidae with remarks on some previously described species. Journal of the Asiatic Society of Bengal 28: 305–309.
  • Theobald W (1876) Catalogue of the Land and Fresh-water Shells of British India. Thacker, Spink, Calcutta.
  • Tryon Jr GW (1886) Manual of conchology, structure and systematic, with illustrations of the species, vol. II, Zonitidae. Academy of Natural Science Philadelphia, Philadelphia.
  • Tryon Jr GW (1887) Manual of conchology, structure and systematic, with illustrations of the species, vol. III, Helicidae: vol. I. Academy of Natural Science Philadelphia, Philadelphia.
  • Tumpeesuwan C, Tumpeesuwan S (2017) Discovery of an overlooked helicarionid land snail (Helicarionidae: Durgellinae) from northeastern Thailand, with description of a new genus and new species, and a note on radula morphology and genital system. The Raffles Bulletin of Zoology 65: 174–181.
  • Vermeulen JJ, Luu HT, Theary K, Anker K (2019) New species of land snails (Mollusca: Gastropoda: Caenogastropoda and Pulmonata) of the Mekong Delta Limestone Hills (Cambodia, Vietnam). Folia Malacologica 27(1): 7–41. https://doi.org/10.12657/folmal.027.001
login to comment