Zoosyst. Evol. 100 (3) 2024, 1135-1154 | DOI 10.3897/zse.100.129455 yee BERLIN Reassessment and phylogenetic position of the overlooked limacoid land snail Jrochomorpha sculpticarina Martens, 1883 (Eupulmonata, Ariophantidae), with the description of a new genus Arthit Pholyotha!, Chirasak Sutcharit!, Somsak Panha!*, Piyoros Tongkerd! 1 Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand 2 Academy of Science, The Royal Society of Thailand, Bangkok 10300, Thailand https://zoobank. org/11F 9B5B3-CEFS8-4C8& 1-943D-E23C9FFS23FB Corresponding author: Piyoros Tongkerd (piyorose@hotmail.com) Academic editor: Frank Kohler # Received 11 June 2024 Accepted 17 July 2024 Published 14 August 2024 Abstract The Malay Peninsula has traditionally been considered to harbour a diverse land-snail fauna, both in terms of a high species richness and a wide variety of conchological traits, especially within the limacoid land snails. A recent survey along the Malay Peninsula of southern Thailand discovered an overlooked limacoid taxon “7rochomorpha” sculpticarina Martens, 1883, previously assigned to genus Trochomorpha of the Trochomorphidae. This genus is herein described as Janbinmorpha gen. nov. based on comparative studies of shell morphology, external features, genital anatomy and radular morphology, as well as analyses of partial sequences of two mitochondrial markers, COI and 16S rRNA, and of one nuclear marker, 28S rRNA. This new genus is characterised by a combination of distinct morphological and anatomical features. The most distinguishing features are a depressed trochiform shell with a keeled last whorl, gametolytic organ without a duct, gametolytic sac with two lobes, and proximal epiphallus encircled with a thick sheath and attached by the penial retractor muscle. In addition, an analysis of the differentiation in mitochondrial and nu- clear markers confirmed that this new genus, first recognised by morphology, is also genetically distinct. The molecular data also confirm that J. sculpticarina comb. nov. is a member of the Ariophantidae and has a close evolutionary relationship to Hemiplecta and Maelamaodiscus. Key Words Helicarionoidea, land snails, Malay Peninsula, phylogeny, systematics, taxonomy Introduction The Malay Peninsula, located in the Indo-Burma biodi- versity hotspot in tropical Asia, is a significant hotspot of diversity and endemism of malacofauna, with various distribution patterns and speciation mechanisms (My- ers et al. 2000; Clements et al. 2006; Foon et al. 2017; Pholyotha et al. 2021c). Southern Thailand is a part of the Malay Peninsula, representing 14% of the total land area of the country (Gardner et al. 2015). This region has a high species diversity and is also uniquely biologically complex, requiring further research to fully understand. The high species richness is associated with a variety of different factors. High relative humidity, a short dry sea- son, a great amount of rainfall, and extensive ranges of limestone karsts and outcrops scattered along this area to- gether with the impact of Quaternary climatic oscillations have significantly influenced the land snail diversification and speciation in this region (Gupta 2005; Clements et al. 2006; Naggs et al. 2006; Ridd et al. 2011; Gardner et al. 2015; Pholyotha et al. 2021c). Basic data on land snail biodiversity in the southern peninsula of Thailand have been continuously collected and studied. However, information beyond the original description of many land-snail taxa 1s scarce. “7rocho- morpha” sculpticarina Martens, 1883 is one such group Copyright Pholyotha, A. et al. 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. 1136 of overlooked species in this region, and only a few taxo- nomic documents have mentioned this species. For exam- ple, in the comprehensive land snail checklists by Panha (1996) and Hemmen and Hemmen (2001), there is no record of this species from Thailand. Originally, Martens (1883) described this species based on specimens from Phuket Province in the South of Thailand and assigned it to Trochomorpha Albers, 1850 in the Trochomorphidae Mollendorff, 1890 because it has a depressed trochiform Shell with a developed peripheral keel. Later, Maassen (2001) reported this species from Peninsular Malaysia under the trochomorphid genus Videna Adams & Adams, 1855. However, as known from several cases of con- servatism and/or convergence in shell form, the general usefulness of the shell features as diagnostic characters has been challenged by studies of genital anatomy and molecular phylogeny (Hyman and Ponder 2010; Kohler and Shea 2012; Jirapatrasilp et al. 2021; Pholyotha et al. 2021a, b, 2022a; Sutcharit et al. 2021; Kohler et al. 2024). During our field survey, many specimens identi- cal to “Jrochomorpha”’ sculpticarina were collected from southern Thailand and Myanmar. Its shell traits are similar to Trochomorpha or Videna, but the living snails resemble several species of the ariophantid genus Hemiplecta Albers, 1850. Moreover, its genital anatomy cannot be assigned to any known limacoid genera. Thus, we herein propose it as a new genus, Janbinmorpha gen. nov. for “Trochomorpha” sculpticarina. For proper tax- onomic classification of this new genus, modern system- atic study is needed. To ensure an accurate taxonomic assessment, we have generated DNA sequence data of this species for both mitochondrial and nuclear markers based on newly-collected samples and have analysed it with the current knowledge of the Asian limacoid snails (Jirapatrasilp et al. 2021; Bhosale et al. 2021; Pholyotha et al. 2021a, c, 2022a, 2023a; Sutcharit et al. 2021). The aims of the present study are to describe the new genus, Janbinmorpha gen. nov., based on a combination of mor- phological, anatomical and molecular information, and to understand the systematic position of the new genus within the limacoid clade. Materials and methods Preparation of specimens, species identification, and morphological studies This study is based on dry shells and ethanol-preserved samples collected from Thailand since 2007 that are now deposited in the Malacological collections of the Chu- lalongkorn University Museum of Zoology (CUMZ), Bangkok, Thailand. Additional specimens from Myan- mar were collected during the Myanmar land snail survey of the Forest Department, Ministry of Natural Resources and Environmental Conservation and Forestry, Myan- mar, the Fauna & Flora International (FFI), and the Ani- mal Systematics Research Unit, Department of Biology, zse.pensoft.net Pholyotha, A. et al.: New limacoid land snail from the Malay Peninsula Faculty of Science, Chulalongkorn University, Thailand (ASRU) in years 2016 and 2017. For the newly collected specimens, the animal use protocol was approved by the Chulalongkorn University Animal Care and Use Com- mittee (CU-ACUC) under approval number 2123023. Before preservation, photographs of several living indi- viduals were taken using a Nikon camera (DSLR D850) with a Nikon 105 Macro lens (AF-S VR Micro-Nikkor 105mm f/2.8G IF-ED). All living specimens were eu- thanised following the standard protocols for animal euthanasia (American Veterinary Medical Association 2020), and were subsequently preserved in 95% (v/v) ethanol for anatomical studies and DNA analyses. Specimens were initially identified based on the litera- ture describing Asian land snail taxonomy (e.g., Martens 1883; Blanford and Godwin-Austen 1908; Solem 1966; Schileyko 2002a, b, 2003; Liew et al. 2009; Pholyotha et al. 2023a; Inkhavilay et al. 2019; Jirapatrasilp et al. 2021; Sutcharit et al. 2021) and compared to the reference collections deposited in the Natural History Museum, London, UK (NHM; NHMUK when citing specimens deposited in the NHM), Forschungsinstitut und Naturmu- seum Senckenberg, Frankfurt am Main, Germany (SMF), and Museum fur Naturkunde, Humboldt University, Ber- lin, Germany (ZMB). Adult shells were used to measure the shell height and shell width using a Vernier caliper, and to count the num- ber of whorls. Photographs of shells were taken using a Nikon camera (DSLR D850) with Nikon 105 Macro lens. The shell sculpture was imaged by scanning electron mi- croscopy (SEM; JEOL, JSM-6610 LV). Preserved snails were dissected using an Olympus SZX2-TR30 stereo- scopic light microscope and were photographed using the Nikon camera (DSLR D850) with Nikon 105 Macro lens. The inner sculpture of genitalia was imaged by a stereo micro-scope with the Cell’D Imaging Software. Radulae were extracted with 10% (w/v) sodium hydroxide solu- tion, cleaned with distilled water, and imaged by scan- ning electron microscopy (SEM; JEOL, JSM-6610 LV). List of abbreviations used in the figures: at (atrium), da (dart apparatus), e (epiphallus), ec (epiphallic cae- cum), es (epiphallic sheath), fo (free oviduct), gs (game- tolytic sac), p (penis), prm (penial retractor muscle), v (vagina), vd (vas deferens). Molecular studies We extracted genomic DNA from small pieces of foot muscle by use of a NucleoSpin DNA extraction kit (Macherey- Nagel, Germany) for animal tissue follow- ing the standard procedure of the manual. Fragments of two mitochondrial genes, cytochrome c oxidase subunit 1 (COI) and 16S rRNA (16S), and of one nuclear gene, 28S rRNA (28S) were amplified by PCR using the uni- versal primer pair LCO1490 and HCO2198 (Folmer et al. 1994), the primer pair 16Sar and 16Sbr (Palumbi et al. 1991), and the primer pair LSU2 and LSU4 (Wade Zoosyst. Evol. 100 (3) 2024, 1135-1154 and Mordan 2000), respectively. The PCR thermal cy- cling conditions for COI, 16S, and 28S were as follows: an initial cycle at 94 °C for 1 min; followed by 40 cycles of 10 s at 98 °C, 30s at 51 °C for COI, 50 °C for 16S and 60 °C for 28S, and 2 min at 72 °C; and followed by a final extension step at 72 °C for 5 min. The amplified products were then sent for commercial sequencing at Bioneer Corporation, South Korea. Chromatograms were manually corrected for misreads, and forward and reverse strands were merged into one sequence file using MEGA v. 7.0 (Kumar et al. 2016). Sequences obtained in this study have been deposited in GenBank under accession numbers: PQ008991—PQ008998, PQ032739-PQ032747, and PQ032728—PQ032738 (Table 1). Information regarding all sequences used in our mo- lecular phylogenetic analyses is provided in Table 1. Se- quence alignments of each gene fragment were generat- ed separately using MAFFT v. 7 in the MAFFT online service (https://mafft.cbrc.jp/alignment/server/) with the default settings (Katoh et al. 2017). Uncorrected pairwise genetic distances (P-distances) were calculated using MEGA v. 7.0 (Kumar et al. 2016) under the option ‘pair- wise deletion of gaps’. For phylogenetic analyses, sequences of the three genes were concatenated into one partitioned dataset and the best- fit model of nucleotide substitution was identified for each gene partition by means of the Bayesian Information Crite- rion using the program Kakusan4 (Tanabe 2011). As sug- 1137 gested by the program Kakusan4, the concatenated dataset was divided into five partitions; the Felsenstein 1981 model with a gamma distribution was chosen for the first codon positions of COI, the Hasegawa, Kishino and Yano 1985 model with a gamma distribution was chosen for the sec- ond codon positions of COI, and the general time-revers- ible model with a gamma distribution was chosen for the third codon positions of COI, 16S and 28S. Phylogenetic relationships were estimated by employing the Maximum Likelihood (ML) and the Bayesian Inference (BI) methods through the online CIPRES Science Gateway (Miller et al. 2010). The ML analyses were performed by applying the GTRCAT model to the entire dataset at the default set- tings of RAxML-HPC2 on ACCESS v. 8.2.12 (Stamatakis 2014), as the program used did not allow for data partition- ing. Branch support was estimated using 1000 bootstrap (BS) replicates. The BI analyses were performed by run- ning 50 million generations of Markov Chain Monte Carlo (MCMC) methods (two simultaneous runs, each with four chains, of which one was heated), as implemented by Mr- Bayes on XSEDE v.3.2.7 (Ronquist et al. 2012). The sam- pling rate of the trees was 1000 generations, with the first 25% of obtained trees being discarded as burn-in. A branch/ clade was considered to be strongly/well supported or sta- tistically significant if the BI posterior probabilities (PP) were > 0.95 and the ML bootstrap (BS) support values were >70% (Hillis and Bull 1993; Felsenstetn 2004; Huelsen- beck and Rannala 2004; Mauro and Agorreta 2010). Table 1. Information of specimens used in the molecular studies with species name, specimen codes, locality name, museum regis- tration numbers, GenBank accession numbers, and references. Taxa Specimen Locality name Museum GenBank accession numbers References number Infraorder Limacoidei Superfamily Helicarionoidea Bourguignat, 1877 Family Ariophantidae Godwin-Austen, 1883 Subfamily Ariophantinae Godwin-Austen, 1883 Janbinmorpha sculpticarina $163-1 Anurak Community Lodge, | CUMZ 15076 - PQ032739 | PQ032728 This study (Martens, 1883), comb. nov. Phanom, Surat Thani, Thailand Janbinmorpha sculpticarina $163-2 | Area near Anurak Community | CUMZ 15076 | PQ008991 | PQ032740 | PQ032729 This study Thailand Janbinmorpha sculpticarina ; Bang Pae Waterfall, Thalang, | CUMZ 15077 | PQO08992 This study (Martens, 1883), comb. nov. Phuket, Thailand Janbinmorpha sculpticarina Tanintharyi, Myanmar FLMNH MF983690 - Slapcinsky and Mulcahy (Martens, 1883), comb. nov. 494197 (Unpublished) Janbinmorpha sculpticarina Tanintharyi, Myanmar FLMNH MF983691 Slapcinsky and Mulcahy (Martens, 1883), comb. nov. 494198 (Unpublished) Ariophanta belangeri (Deshayes, Kagal, Kolhapur, Maharashtra, Bhosale et al. (2021) BNHS GAS 73 MW583023 1832) India Ariophanta intumescens (Blanford, Mhalunge, Kolhapur, BNHS GAS 74 MW583024| Bhosale et al. (2021) 1866) Maharashtra, India Cryptozona bistrialis (Beck, 1837) KX378390 Euplecta gardener Preifer, 1848) Tad Pha Suam, Paksong, Champasak, Laos Botanic Garden, Singapore Hemiplecta distincta (Pfeiffer, 1850) H54 Hemiplecta humphreysiana (Lea, 1840) Ayyagari and Sreerama (2020) Wade et al. (2006) Sutcharit et al. (2021) | = | = | AY841311 CUMZ 5267 | MT654617 | MT651533 | MT651588 CUMZ 5158 | MT364994 | MT365775 | MT365719 | Pholyotha et al. (2021c) Hemiplecta pluto (Pfeiffer, 1863) Wat Pa Pha, Khamkeut, Bolikhamxay, Laos Khasiella pingoungensis (Godwin- Austen, 1888) MY51-1 |Pyinyaung, Mandalay, Myanmar} CUMZ 14560 | PQ008993 | PQ032741 | PQ032730 CUMZ 5266 | MT364995 | MT365776 | MT365720 | Pholyotha et al. (2021c) This study zse.pensoft.net 1138 Pholyotha, A. et al.: New limacoid land snail from the Malay Peninsula Taxa Specimen Locality name Museum GenBank accession numbers References Codes registration Col 16S 28S number Khasiella pingoungensis (Godwin- Pyinyaung, Mandalay, Myanmar | CUMZ 14560 | PQ008994 | PQ032742 | PQ032731 This study Austen, 1888) Mariaella dussumieri Pfeiffer, 1855 Ramling Temple, Kolhapur, | ZS! Moll 1789 - — MW583030} Bhosale et al. (2021) Maharashtra, India Maelamaodiscus somsakpanhai Phra Wor Shine, Mae Sod, Tak, | CUMZ 14295 - PQ032732 This study Sutcharit & Pholyotha, 2023 Thailand Maelamaodiscus somsakpanhai Wat Phothikun, Mae Sod, Tak, | CUMZ 14296 - PQ032733 This study Sutcharit & Pholyotha, 2023 Thailand Megaustenia praestans Gould, MY47 | Golden valley near Bat Cave, PQ032743 | PQ032734 This study 1843) Hpa-An, Myanmar (Burma) Megaustenia sp. Pa Ma-muang Bureau of CUMZ 7241 | MT364990 | MT365778 | MT365722 | Pholyotha et al. (2021d) Monks, Noen Maprang, Phitsanulok, Thailand [ie | Ratnadvipia sp. r_- |. Srilanka + - | - | — | AY841312 [Wade et al. (2006) Subfamily Macrochlamydinae Godwin-Austen, 188: Macrochlamys aspides (Benson, MY8 = Nya Mountain, Hpa An, | CUMZ 7135 | MT364986 | MT365761 | MT365705 | Pholyotha et al. (2021c) 1863) Kayin, Myanmar Macrochlamys pedina (Benson, Khandala,Maharashtra, India | BNHS GAS MW583026}| Bhosale et al. (2021) Macrochlamys indica Godwin- Shivaji University, BNHS GAS 82 - MW583025| Bhosale et al. (2021) Austen, 1883 Kolhapur,Maharashtra, India Macrochlamys sp.1 Laos CUMZ 15262 | PQ008996 | PQ032744 | PQ032735 This study Macrochlamys sp.2 PQ032745 | PQ032736 This study Sarika resplendens (Philippi, 1847) MT365763 | MT365707 | Pholyotha et al. (2021c) Ratchaburi, Thailand Sarika obesior (Martens, 1867) Wat Nong Phlap, Hua Hin, CUMZ 7233 | MT364977 | MT365768 | MT365712 | Pholyotha et al. (2021c) Prachuap Khiri Khan, Thailand Taphrenalla diadema (Dall, 1897) Wat Tham Sumano, CUMZ 7175 | MT364940 | MT365729 | MT365673 | Pholyotha et al. (2021c) Srinagarindra, Phatthalung, Thailand Taphrenalla incilis Pholyotha & Tham Khao Ting, Palian, Trang,| CUMZ 7209 | MT364963 | MT365746 | MT365690 | Pholyotha et al. (2021c) Panha, 2021 Thailand Varadia amboliensis Bhosale, - Amboli, Maharashtra, India BNHS GAS - - MW583027}| Bhosale et al. (2021) Thackeray, Muley & Raheem, 2021 129 Subfamily Ostracolethinae Simroth, 1901 Parmarion martensi Simroth, 1893 NE100 | Wat Tham Pha Khao, Si Wilai, | CUMZ 15264 | PQ008998 | PQ032746 | PQ032737 This study Bueng Kan, Thailand Family Helicarionidae Bourguignat, 1877 Aenigmatoconcha clivicola NE68 Wat Tham Pha Lom, Mueang, | CUMZ 7929 |MW703614} PQ032747 | PQ032738 | This study; Pholyotha et Tumpeesuwan & Tumpeesuwan, 2017 Loei, Thailand al. (2021d) Chalepotaxis infantilis (Gredler, Cha-int2 | Guanyindong, Zhangjiajie Shi, NHMW KX027275 - KX027276 | Pal-Gergely et al. (2016) 1881) Hunan, China 111548 Durgella sp. Tham Lom Tham Wang, Si MT365777 | MT365721 | Pholyotha et al. (2021c) Samrong, Sukhothai, Thailand Eurychlamys platychlamys Sagar Upavan, Mumbai, BNHS GAS 10 MW583029} Bhosale et al. (2021) (Blanford, 1880) Maharashtra, India Fastosarion brazieri (Cox, 1873) Mossman, Queensland, AY014099 Wade et al. (2001) Australia Satiella sp. MW583028] Bhosale et al. (2021) india Sophina schistostelis (Benson, 1859)| MY24 Sanbel Cave, Mawlamyine, | CUMZ 5195 eau MN888602 | MN892653) Sutcharit et al. (2020a) Mon, Myanmar Superfamily Trochomorphoidea Morch, 1864 Family Dyakiidae Gude & Woodward, 1921 Trochomorpha sp.1 Tham Khao Chakan, Khao ORO76723 | ORO76740 | Pholyotha et al. (2023a) Chakan, Sa Kaeo, Thailand Trochomorpha sp.2 Wat Tham Pha Lom, Mueang, | CUMZ 14871 | ORO75933 | ORO76724 | ORO76741 | Pholyotha et al. (2023a) Loei, Thailand Trochomorpha sp.3 Talod Cave, Thung Song, | CUMZ 14873 | ORO75934 | ORO76725 | ORO76742 | Pholyotha et al. (2023a) Nakhon Si Thammarat, Thailand Trochomorpha froggatti (Iredale, Batangan, Kinabatangan, RMNH. MK851194 | MK851432 | MK851503 Hendriks (2020) 1941) Sabah, Malaysia 5005011.01 Videna metcalfei (Pfeiffer, 1845) - Batangan, Kinabatangan, RMNH. MK851205 | MK851445 | MK851515 Hendriks (2020) Sabah, Malaysia 5005031.01 Family Geotrochidae Schileyko, 2002 Geotrochus rhysa (Tillier & Bouchet, Mount Kinabalu, Sabah, BORMOL | MK779474 | MK334188 | ORO76749 | Chang and Liew (2021), 1989) Malaysia 6347 Pholyotha et al. (2023a) Geotrochus kitteli Vermeulen, Liew & Mount Kinabalu, Sabah, BORMOL | MK779460 | MK334194 | ORO76744 | Chang and Liew (2021), Schilthuizen, 2015 zse.pensoft.net 6406 Malaysia Pholyotha et al. (2023a) Zoosyst. Evol. 100 (3) 2024, 1135-1154 Specimen Codes Taxa Locality name Family Euconulidae Baker, 1928 Siamoconus geotrochoides Pholyotha, 2023 Siamoconus boreas Pholyotha, 2023 N70-3 Ban Tha Si, Mae Mo, Lampang, Thailand NE46-1 | Wat Tham PhaLom, Mueang, | CUMZ 14298 | ORO75923 | ORO76716 | ORO76735 Loei, Thailand 1139 Museum GenBank accession numbers References registration Col 16S 28S number Pholyotha et al. (2023a) CUMZ 14310 | ORO75905 | ORO76701 | ORO76726 | Pholyotha et al. (2023a) Superfamily Gastrodontoidea Tryon, 1866 Family Oxychilidae Hesse, 1927 Oxychilus alliarius (Miller, 1822) | = - | Deepdale, Derbyshire, UK | = - —— {MNO22739] = - —_{MNO22673] Saadi and Wade (2019) Superfamily Limacoidea Batsch, 1789 Family Vitrinidae Fitzinger, 1833 Vitrina pellucida (Miller, 1774) | - Kirkdale, Derbyshire, UK | INO22672 | Saadi and Wade (2019) : | MNO22738] = Infraorder Arionoidei Gray, 1840 Superfamily Arionoidea Gray, 1840 Family Philomycidae Gray, 1847 Meghimatium bilineatum (Benson, - 1842) Mauritius - MNO22745 - MNO22678 | Saadi and Wade (2019) Family Arionidae Gray, 1840 Arion hortensis Férussac, 1819 - Kirkdale, Derbyshire, UK Results Molecular phylogeny Molecular phylogenetic trees were reconstructed based on the concatenated mitochondrial COI and 16S sequences, and nuclear 28S sequences obtained from 53 individuals, including 31 ariophantids, 7 helicarionids, 5 trochomor- phids, 2 dyakiids, 2 geotrochids, 2 euconulids, 1 oxychilid, and 1 vitrinid together with 2 species of arionoideans for the more distantly related outgroups to root the phylogenet- ic tree. The suitable outgroups in this study were selected based on the recent phylogenetic trees presented by Bho- sale et al. (2021) and Pholyotha et al. (2023a). The final concatenated mtDNA + nDNA dataset contained 39 COI sequences, with an alignment length of 691 sites (377 con- served sites, 260 parsimony informative sites, and 305 vari- able sites), 32 sequences of 16S, with an alignment length of 522 sites (215 conserved sites, 204 parsimony informa- tive sites, and 249 variable sites), and 50 sequences of 28S, with an alignment length of 557 sites (387 conserved sites, 117 parsimony informative sites, and 164 variable sites). In this study, both Maximum Likelihood (ML) and Bayesian Inference (BI) analyses produced trees with iden- tical topologies; therefore, only the tree topology from the ML analysis is presented in Fig. 1. Analyses of the com- bined COI + 16S + 28S dataset of about 31 sequences of at least 24 species representing all known ariophantid genera that have available DNA information from Asia have con- firmed the monophyly of the Janbinmorpha gen. nov. as delineated herein. However, our results indicated that the phylogenetic relationships within the Limacoidei are still unresolved, especially a clade of the Helicarionoidea (in- cluding Ariophantidae and Helicarionidae; Fig. 1). Although the phylogeny is not fully resolved, it high- lights or identifies the phylogenetic positions of Janbin- morpha gen. nov. and some ariophantid genera (such as Megaustenia, Khasiella, Parmarion, and Maelamaodiscus) for the first time. The new genus was grouped together with - MNO22 744 - KU341315 | Saadi and Wade (2019) the Maelamaodiscus + Hemiplecta clade with high support by BI (BS = 62%, PP = 0.97). However, the phylogenetic relationships within the Janbinmorpha + Maelamaodis- cus + Hemiplecta clade could not be resolved in this study (Fig. 1). This clade was retrieved as the sister clade to the Khasiella + Macrochlamys aspides + Sarika + Taphrenalla clade with good support (BS = 71%, PP = 1). Relationships within the latter clade were resolved in this study (Fig. 1). Pairwise comparisons of COI sequences showed that conspecific specimens of Janbinmorpha sculpticarina comb. nov. were differentiated by means of 0% to 4.4% uncorrected p-distances (Table 2), whereas 16S and 28S sequences of conspecific specimens differed by 0%. Comparing Janbinmorpha gen. nov. and other ariophan- tid genera, the uncorrected p-distances of the COI, 16S and 28S sequences ranged from 12.2% (between the new genus and Japhrenalla) to 14.8% (between the new ge- nus and Parmarion) for COI (Table 3), from 11.8% (be- tween the new genus and Hemiplecta) to 17.8% (between the new genus and Cryptozona) for 16S (Table 4), and from 2.7% (between the new genus and Hemiplecta) to 6.0% (between the new genus and Cryptozona) for 28S (Table 5). Taxonomy and systematics Superfamily Helicarionoidea Bourguignat, 1877 Family Ariophantidae Godwin-Austen, 1883 Subfamily Ariophantinae Godwin-Austen, 1883 Janbinmorpha Pholyotha & Panha, gen. nov. https://zoobank. org/953A9F87-2E64-4A 1 1-AFD6-061303E94409 Type species. Zrochomorpha_ sculpticarina Martens, 1883; here designated. Etymology. The name combines “Janbin” in refer- ence to the shape of an unidentified flying object (UFO) in the Thai language, and similar to the shell shape of zse.pensoft.net 1140 -78/0.95 59/0.91 60/0.66' 98/1 aoe _55/0.80 84/0.80 98/1 oa oidee 100/1 Helicariot 100/1 29/0.73 34/- 59/0.58 33/- 88/0.99 59/0.95 94/" Helicarionidae 7210.94 100/1 95/1 82/0.92 100/1 44/0.97 100/1 100/1 N70-3 65/0.52 0.03 NE100 Parmarion martensi Ariophanta belangeri Ariophanta intumescens Euplecta gardeneri C19 Megaustenia sp. 100/14 “Trochomorpha” sp. FLMNH 494198 100/0.79' S163-1 “Trochomorpha” sculpticarina* 100/1 Videna metcalfei* Pholyotha, A. et al.: New limacoid land snail from the Malay Peninsula J. sculpticarina Cryptozona bistrialis Ratnadvipia sp. MY47 Megaustenia praestans* “Trochomorpha’” sp. FLMNH 494197 $208-2 “Trochomorpha’” sculpticarina* P $163-2 “Trochomorpha’ sculpticarina* Janbinmorpha gen. nov. W109 Maelamaodiscus somsakpanhai* 100/1 # W93-2 Maelamaodiscus somsakpanhai* H54 Hemiplecta distincta H63 Hemiplecta pluto H7 Hemiplecta humphreysiana* W65 Sarika obesior W4 Sarika resplendens* MY8 Macrochlamys aspides MY51-2 Khasiella pingoungensis MY51-1 Khasiella pingoungensis $69 Taphrenalla incilis $46 Taphrenalla diadema* Varadia amboliensis* Macrochlamys pedina Macrochlamys indica 100/1 ! MY4 Macrochlamys sp.2 L1 Macrochlamys sp.1 Mariaella dussumieri* Chalepotaxis infantilis* 100/1 Satiella sp. MY24 Sophina schistostelis* N15 Durgella sp. Eurychlamys platychlamys* Fastosarion brazieri NE68 Aenigmatoconcha clivicola* NE80 Trochomorpha sp.2 Trochomorpha froggatti $185-2 Trochomorpha sp.3 NE74 Trochomorpha sp.1 H23 Quantula striata* 100/1 eepiudiowoysol H42 Phuphania globosa* Geotrochus kitteli Geotrochus rhysa Siamoconus boreas NE46-1 Siamoconus geotrochoides* Vitrina pellucida* Oxychilus alliarius Meghimatium bilineatum Arion hortensis Figure 1. Maximum likelihood phylogram based on analyses of concatenated COI, 16S, and 28S sequences. Numbers on branches indicate nodal support by ML bootstrap (BS) and Bayesian posterior probabilities (PP) analyses. Asterisk indicates the type species of its corresponding genus. The sample code in front of species name indicates voucher samples as shown in Table 1. Living speci- men of Janbinmorpha sculpticarina (Martens, 1883), comb. nov. from Phang-nga Province, not to scale. this new genus, and “morpha” in reference to the simi- larity of shell morphology between this new genus and the genus Trochomorpha. Diagnosis. Shell dextral, umbilicated, depressed, len- ticular, ribbed, with keeled last whorl. Animal with three dorsal lobes; foot tripartite; caudal foss present; caudal zse.pensoft.net horn very reduced. Genitalia having epiphallic caecum, flagellum and dart apparatus; proximal epiphallus encir- cled with thickened muscular epiphallic sheath; gameto- lytic organ without duct and gametolytic sac consisting of two bulbs. Radula with tricuspid central tooth; unicuspid or bicuspid lateral teeth; unicuspid marginal teeth. Zoosyst. Evol. 100 (3) 2024, 1135-1154 1141 Table 2. Estimates of cytochrome c oxidase I (COI) sequence divergence (uncorrected p-distances) within Janbinmorpha sculpti- carina comb. nov. Sequences of Janbinmorpha sculpticarina J. sculpticarina $163-2 J. sculpticarina S208-2 0.027 J. sculpticarina FLMNH 494197 0.044 J. sculpticarina FLMNH 494198 0.044 Description. See below under the type species. Constituent species. This new genus contains only the type species, J. sculpticarina comb. nov. Distribution. Currently known only from the Malay Peninsula. Remarks. Janbinmorpha gen. nov. is clearly discrim- inated from all other Southeast Asian limacoid genera (e.g., Hemiplecta, Holkeion Godwin-Austen, 1908, Sia- moconus Pholyotha in Pholyotha et al. 2023a, Videna and Trochomorpha) by the shape of the gametolytic sac and by the attachment of the penial retractor muscle. This new genus has no gametolytic duct and the gametolytic sac 1s divided into two lobes, while the gametolytic sac of all other limacoid genera is not divided into two lobes and most of them have a gametolytic duct. The penial retrac- tor muscle of this new genus 1s attached to two regions (epiphallic caecum and epiphallic sheath), while all oth- er limacoid genera have the retractor muscle attached to either the epiphallic caecum or epiphallus (Blanford and Godwin-Austen 1908; Solem 1966; Schileyko 2002a, b, 2003; Sutcharit et al. 2020a, 2021; Sutcharit and Panha 2021; Pholyotha et al. 2021b, c, 2022a, b, 2023b, c). Janbinmorpha gen. nov. also differs from Videna in having a long dart apparatus and the position of gameto- lytic organ on female side, while the latter genus has no dart apparatus and gametolytic duct opening into the base of the penis (Schileyko 2002a). Janbinmorpha gen. nov. is conchologically very simi- lar to the Indian helicarionoidean genus Sivel/a Blanford, 1863. However, this new genus differs by having a long dart apparatus, a straight epiphallic caecum, and no ga- metolytic duct. In comparison, Sivel/a has a relatively short gametolytic duct and a subglobular gametolytic sac, and does not have a dart apparatus or epiphallic caecum (Godwin-Austen 1918; Schileyko 2003). In addition, the molecular phylogeny (Fig. 1) supports a distinct lineage of the monotypic Janbinmorpha gen. nov. from genera Hemiplecta, Siamoconus, Videna and Trochomorpha. Currently, genetic sequences of Holkeion and Sivella are not available in the online GenBank se- quence database for phylogenetic analysis. Janbinmorpha sculpticarina (Martens, 1883), comb. nov. Figs 1-5, 6A Trochomorpha sculpticarina Martens, 1883: 136, pl. 25, figs 13-16. Type locality: “insulam Salanga” [Phuket Province, Thailand]. Videna sculpticarina—Basch and Solem 1971: 95. Maassen 2001: 116. J. sculpticarina $163-2 J. sculpticarina S208-2 J. sculpticarina FLMNH J. sculpticarina FLMNH 494197 494198 0.043 0.043 0.000 Type material examined. Syntype ZMB/Moll 58132 (1 shell; Fig. 2A) ex. Paetel collection from Salanga [Phuket Province, Thailand]. Syntypes ZMB/Moll 34164 (2 shells; Fig. 2B) ex. Weber collection from Salanga [Phuket Province, Thailand]. Other material examined. MyANMAr-Southern. Bud- dha Cave, Lenya City, Tanintharyi Region, 11°13'46.2"N, 99°10'34.3"E: CUMZ 15254 (1 preserved specimen). THAILAND. Salanga [Phuket Province, Thailand]: ZMB/ Moll 75765 (1 shell) ex. Webb collection, ZMB/Moll 88249 (1 shell) ex. Kammaun collection, SMF 179828/2 (2 shells; Fig. 2C), SMF 179829/2 (2 shells) ex. Mollen- dorff collection, NHMUK 1883.3.27.4 (1 shell). Phuket: Bang Pae Waterfall, Thalang District, 8°02'21.9"N, 98°23'27.8"E: CUMZ 15077 (4 shells and 4 preserved specimens; Fig. 2D), 15161 (3 shells). Chumphon: Tham Nam Lod Thepnimit Bureau of Monks, Sawi District, 10°22'37.8"N, 99°00'41.2"E: CUMZ 15157 (2 shells). Wat Tham Sanook, Mueang District, 10°28'51.4"N, 99°04'28.3"E: CUMZ 15156 (1 shell). Area in Pak Song, Phato District, 9°46'10.8"N, 98°40'42.9"E: CUMZ 15255 (1 preserved specimen). Ranong: Near Wat Pa Thung Rong, Kapoe District, 9°37'00.2"N, 98°37'52.3"E: CUMZ 15256 (2 preserved specimens). Phang-nga: Wat Khiriwong (Tham Kob), Thap Put District, 8°31'55.9"N, 98°34'38.4"E: CUMZ 15163 (1 shell). Wat Pa Dok Daeng, Takua Pa District, 8°44'28.6"N, 98°18'24.3"E: CUMZ 15151 (3 shells and 3 preserved specimens; Fig. 2F). Ton Phrai Waterfall, Thai Mueang District, 8°26'10.4"N, 98°18'33.3"E: CUMZ 15150 (1 shell and 2 preserved specimens). Nature study route | in Ko Surin Nuea, Khura Buri District, 9°27'01.1"N, 97°52'39.1"E: CUMZ 15164 (1 shell). Nature study route 4 in Ko Surin Nuea, Khura Buri District, 9°25'46.3"N, 97°52'14.0"E: CUMZ 15152 (2 preserved specimens). Nature study route 3 in Ko Su- rin Tai, Khura Buri District, 9°23'48.2"N, 97°52'02.8"E: CUMZ 15162 (2 shells). Surat Thani: Nature trail at Ratchaprapha Dam, Ban Ta Khun District, 8°58'19.1"N, 98°48'16.7"E: CUMZ 15154 (29 shells). Area in Khiri Rat Nikhom District, 9°04'13.1"N, 98°59'45.6"E: CUMZ 15153 (8 shells; Fig. 2E). Area near Anurak Communi- ty Lodge, Klong Sok, Phanom District, 8°53'05.6"N, 98°41'12.6"E: CUMZ 15076 (2 preserved specimens). Nakhon Si Thammarat: Area in Khao Noi, Sichon Dis- trict, 8°56'17.3"N, 99°48'54.7"E: CUMZ 15155 (1 shell). Krabi: Toh Chong Toh Yuan Shrine, Ao Luek District, 8°22'25.5"N, 98°44'09.7"E: CUMZ 15160 (1. shell). Trang: Khao Ting Cave, Palian District, 7°09'32.3"N, 99°48'10.3"E: CUMZ 15158 (1 shell). zse.pensoft.net Pholyotha, A. et al.: New limacoid land snail from the Malay Peninsula 1142 XA vicO veco vecod cc T6TO vic0 ie 9ST'°0 Te 0c vicO L0¢'0 Sec0 81¢0 8910 2910 [ZO e200 + 120 8c1'0 61 8T ‘ssouonbds JUSUISeIY BUDS [QD JO d0ULISIP-d pa}dd1IONUN UO pase VIOUS 1OY}O PUL ‘AOU “Ud YYAIOWUIGUPL UddM4OQ JOUIBIDAIP AICUOTIN[OAD JO SOYeUITISY *¢ I[qUy, 80¢'0 €0¢°0 ISTO SLT 0 SET O 9ETO TE0'0 LT 6610 O1¢'0 ELT O S6T'0 vLT0 IZT0O LvT0 6v0'0 oT GT vT eT cl TT OT 60 c0¢'0 S0¢'0 8r1'0 ESTED SIT O 9vT'0 92T 0 1910 ETO EETO LETO 9ET'O vvt'o ScT0 velo S0'0 80 S810 S6l'0 Lvl 0 69T'O 6cT 0 cST 0 EvT'O 9ST0 9ET'O LvT0 cet 0 EETO SvT0 vel'0 8c1'0 9ITO S0'0 LO L020 L120 89T'0 SLTO EET O SSTO LET O OLT'O ame) vvl'o ESTO stom ie) SvTO EETO SETO sIl'0 1210 €ETO 90 SO coc Q S1c'0 8ST'0 L9OTO SET O ISTO 6€T'O 6ZT'0 evt0 SET'O SST0 6ST'0 6ST'0 evtd cvt0 vET‘O LETO 9ET'O ETO 860°0 vO 6120 C020 ISTO SSTO TET‘O ISTO vET'O £9L0 vET‘O LETO 6€T'0 vET‘O OST'O 6€T'0 9ETO OITO cel 0 TET‘O cll 0 9ETO 080°0 €0 cO €22°0 EN Ee SIZ'0 winnjewiysayy ZZ 0910 PULA TZ e/T0 snjlyOAxO OZ fGT‘0 BUuSpIA 6T 3910 eydsJOWOYIOLL BT 6Z1'0 SnUuOIOUIeIS /T OLU0 SNYI04}095) OT yyl0 elueydnyd GT /yl0 ejnquend vT ISTO eulydos €T 8710 e//984NgG ZT 9ST‘0 sixejodajey) TT I€T'O eyouos0}ewsiusy OT BrT'0 uoLieuLied 60 2210 eyjeuasydey go O€T'0 eyes £0 Ivl'0 sAwejyo0s9e] 90 8ZT'0 E/JaISeyy GO SpT‘0 eluajsnesa] 70 9210 ey2a/dIWIaH €0 BETO eu0zo}dhiy ZO ie eydsowuiquer [OQ 10 eiauayy zse.pensoft.net 1143 Zoosyst. 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Evol. 100 (3) 2024, 1135-1154 ce €90°0 Té 1Z0°0 LL0'0 O€ 620°0 660°0 790°0 62 cOT'O 9IT'0 £60°0 €60°0 82 880°0 cOTO €80°0 8Z0°0 9€0'0 9200 Le 9¢ Ge ve Ee ce Té 0c 6T 620°0 S80°0 uouy Ze c60'0 OOT‘O uinnewiysayy TE v90'0 1Z0°0 PUI OF 790'0 €Z0°0 snjlyoAxO 6Z 6£0°0 680'0 eUuap!IA BZ €90'°0 €20'0 eYydsOWwOoYysIoLL /Z c90°0 690°0 SNUODOWIS 9Z SZ0°0 180°0 sny204}095) GZ v80'0 v80'0 elueydnud yz 680°0 v60°0 ejnjuend €Z vEO'O 8€0°0 eulydos 2Z 920°0 920'0 eyanes 12 TS0°0 Sv0'0 uolesoj}sey OZ €v0'0 Lv0'0 sAwiejyohing 6T 8200 e//83.1NG ST = sixejodajey) LT eBYyDUOIO}EWISIUaY OT UOLIEULEd ST EIPEAEA VT eyjeuasydel eT eyes CT sAwejyooi9e] TT E/[/AISeYY OT eldiapeujey 60 eluajsnesayy] 80 eyjeenem LO snosipoewe/aeyy 90 e}99/dIWaH GO e}99/dNJ yO eu0zo}dAlg €0 ejueydouy ZO eydsowuiquer TO 8T LI B19uas) ‘ponunUoD *s aquL zse.pensoft.net 1146 Diagnosis. Shell depressed and lenticular; body whorl keeled on periphery; surface with prominent radial ribs and reticulated microsculptures; whorls 6 and increasing regularly; aperture obliquely crescent-shaped with sim- ple peristome; umbilicus open and funnel shaped. Animal dark gray with pigmentation of yellow to orange dots or patches; one stripe at middle of body running from ante- rior to posterior; three dorsal lobes present; foot tripar- tite; caudal foss present; caudal horn very reduced. Gen- italia having very short flagellum; two bundles of penial Pholyotha, A. et al.: New limacoid land snail from the Malay Peninsula retractor muscle; epiphallic sheath thickened and entirely covering proximal epiphallus; gametolytic duct absent; gametolytic sac having two lobes; dart apparatus present. Description. Shell (Figs 2, 3A—D). Shell dextral, depressed, lenticular, medium-sized (shell width up to 19.8 mm, shell height up to 9.3 mm), thickened, rather opaque, yellowish brown to dark brownish. Embryonic Shell about 2% whorls, with raised growth lines form- ing riblet-like textures (Fig. 3A, B). Whorls 6, convex, regularly increasing, separated by shallow suture. Later Figure 2. Shell of Janbinmorpha sculpticarina (Martens, 1883), comb. nov. A. Syntype from Salanga [Phuket Province]: ZMB/ Moll 58132; B. Syntypes from Salanga [Phuket Province]: ZMB/Moll 34164; C. Specimen from Salanga I., Malaysia [Phuket Island, Phuket Province, Thailand]: NHMUK 1888.3.27.4; D. Specimen from Phuket Province: CUMZ 15077; E. Specimen from Surat Thani Province: CUMZ 15153; EF. Specimen from Phang-nga Province: CUMZ 15151 using for SEM imaging. zse.pensoft.net Zoosyst. Evol. 100 (3) 2024, 1135-1154 whorls distinct, regular, curved radial ribs, with fine, widely regularly spaced radial ribs, with reticulated mi- crosculptures; and 4—5 distinct spiral threads close to the periphery, positioned above the radial ribs (Fig. 3C, D). Last whorl distinctly angular, compressed at periphery, and moderately convex below periphery. Spire rather el- evated. Aperture obliquely crescent-shaped; peristome simple; columellar margin simple and slightly reflected near umbilicus. Umbilicus opened, deep, slightly less ROO Te Ma yy ues Bon 1147 than one-third the width of the last whorl from the bottom view of the shell. Genitalia (Fig. 4). Atrium (at) enlarged and short. Pe- nis (p) enlarged and short cylindrical. Inner wall sculp- tured with small, curly and closely packed oblique pe- nial pilasters extending through entire penis chamber; penial verge absent; junction between penis and epiphal- lus thickened (Fig. 4B). Epiphallus (e) long cylindrical tube: proximal epiphallus longer than penis and vagi- Figure 3. Scanning electron microscope (SEM) images of shell surface and radula of aabinmei bia sculpticarina (Martens, 1883), comb. nov. A-D. Specimen CUMZ 15151, showing shell surface; A. Protoconch viewed from above; B. Zoomed-in view of proto- conch; C. Body whorl viewed from above; D. Zoomed-in view of body whorl; E. Specimen CUMZ 15077, showing radula; central tooth indicated by ‘C’. zse.pensoft.net 1148 Pholyotha, A. et al.: New limacoid land snail from the Malay Peninsula Figure 4. Genitalia of Janbinmorpha sculpticarina (Martens, 1883), comb. nov. A. Specimen from Surat Thani Province: CUMZ 15076, showing general view of genital system; B. Specimen from Phang-nga Province: CUMZ 15150, showing internal structure of penis and epiphallus; C. Specimen from Phuket Province: CUMZ 15077, showing gametolytic organ; D. Specimen from Phang- nga Province: CUMZ 15150, showing gametolytic organ. White arrowhead indicates the end of the penis. na, and encircled with thickened epiphallic sheath (es); distal epiphallus smaller diameter than proximal part. Epiphallic caecum (ec) large, straight, and located near middle of epiphallus. Penial retractor muscle (prm) rath- er thickened and divided into two bundles: one bundle attached to tip of epiphallic caecum and another bundle attached to distal end of epiphallic sheath (Fig. 4A). Fla- gellum (f) very short or nearly absent. Vas deferens (vd) zse.pensoft.net small tube continuing from free oviduct to near distal tip of epiphallus. Vagina (v) long cylindrical tube, about two times pe- nis length. Dart apparatus slender, long and located on mid-vaginal length. Gametolytic organ with undistin- guished duct; gametolytic sac (gs) divided into two lobes separated at base: one large and bulbous shape, and an- other small and long-slender tube (Fig. 4A, C, D). Free Zoosyst. Evol. 100 (3) 2024, 1135-1154 1149 Gulf of Thailand q am Surat Thani Phang-nga e D3 ae | y 60 1 MALAYSIA . 4 \ a i $ we Figure 5. Map of the Malay Peninsula in southern Thailand and the southernmost tip of Myanmar showing the sampling sites. Lo- calities where the living specimens were collected are indicated by numbers on map, not to scale. oviduct (fo) long cylindrical, approximately as long as vagina length. Oviduct enlarged with lobules; prostate gland bound to oviduct. Radula (Fig. 3E). Teeth arranged in a wide-angle U-shape with half-row formula: 1-+~11—15)—56. Central tooth relatively symmetrical tricuspid; mesocone large and triangular shape with pointed cusp; ectocones very small with dull cusp. Lateral teeth unicuspid or asym- metrical bicuspid with mesocone large with pointed cusp and ectocone nearly wanting with dull cusp. Lateral teeth larger than marginal teeth. Marginal teeth starting at ap- proximately row number 11 to 15 with obliquely elongate unicuspid form; outermost teeth narrower and shorter than inner teeth. zse.pensoft.net 1150 Janbinmorpha sculpticarina A E Pholyotha, A. et al.: New limacoid land snail from the Malay Peninsula Hemiplecta éymatium BB the $ te Fes at e : o j : a ~ * Siamoconus geotrochoides Pseudoplecta bijuga F Figure 6. Representative living limacoid snails with a depressed trochiform shell from Thailand and the Malay Peninsula. A. Janbinmorpha sculpticarina (Martens, 1883), comb. nov. in the Ariophantidae; B. Hemiplecta cymatium (Pfeiffer, 1856) in the Ariophantidae; C. Holkeion anceps (Gould, 1843) in the Ariophantidae; D. Siamoconus geotrochoides Pholyotha, 2023 in the Eu- conulidae; E. Trochomorpha sp.2 in the Trochomorphidae; F. Pseudoplecta bijuga (Stoliczka, 1873) in the Dyakiidae. External features (Figs 1,5, 6A). Living snails with dark gray body and more or less distinct pale milky or yellow to orange stripe running from head to caudal horn; entire ani- mal with pigmentation of yellow to orange dots or patches. Eye stalks long and pale blackish; lower tentacles shorter and paler in colour. Mantle lobes or mantle extensions well developed, crescent-shaped, yellow to orange, divided into three dorsal lobes, and somewhat thickened near their mar- gins. Right dorsal lobe prominent, broadly crescent-shaped, and larger than both anterior and posterior left dorsal lobes. Anterior left dorsal lobe broadly crescent-shaped; posterior left dorsal lobe relatively long crescent-shaped. Sole evenly tripartite, pedal groove very strong. Foot margin yellow to orange. Caudal foss cup-shaped; caudal horn very reduced, short, not overhung, and yellow to orange. Distribution. (Fig. 5). This species is apparently re- stricted to the southern peninsula of Thailand. Major pop- zse.pensoft.net ulations of J. sculpticarina comb. nov. occur in the Phuket Range, while a few populations can be found in Nakhon Si Thammarat and the southern part of the Tenasserim ranges. This species was also recorded from the Pulau Aur Island, Malaysia (Basch and Solem 1971), but this record needs to be confirmed with the newly collected specimens. Remarks. According to the limacoid snails with a de- pressed trochiform shell from Thailand and the Malay Pen- insula, Janbinmorpha sculpticarina comb. nov. (Fig. 6A) is conchologically similar to some helicarionoidean spe- cies, for example Hemiplecta cymatium (Pfeiffer, 1856) (Fig. 6B) and Holkeion anceps (Gould, 1843) (Fig. 6C), and is also similar to some trochomorphoidean species, such as Siamoconus geotrochoides Pholyotha in Pholyotha et al. 2023a (Fig. 6D), Trochomorpha sp.2 (Fig. 6E), and Pseudoplecta bijuga (Stoliczka, 1873) (Fig. 6F). Howev- er, J. sculpticarina comb. nov. can be distinguished by its Zoosyst. Evol. 100 (3) 2024, 1135-1154 genitalia in having two lobes of the gametolytic sac, no gametolytic duct, and a penial retractor muscle attached to the epiphallic caecum and epiphallic sheath. In compari- son, Hemiplecta cymatium possesses a bulbous gametolyt- ic sac, no gametolytic duct, and a penial retractor muscle attached to epiphallic caecum only (Sutcharit and Panha, unpublished data), while Holkeion anceps has an elongate gametolytic duct and a penial retractor muscle attached to the epiphallic caecum (Pholyotha et al. 2023b). The tro- chomorphoideans, S. geotrochoides and Trochomorpha sp.2 differ by having a long gametolytic duct and a penial retractor muscle attached to the epiphallus (Pholyotha et al. 2023a; Pholyotha and Panha, unpublished data). In ad- dition, P. bijuga possesses a gametolytic organ located on the amatorial organ and a penial retractor muscle attached to the epiphallus (Jirapatrasilp et al. 2021). Compared with other taxa having a depressed tro- chiform shell, and regardless of genitalia data, J. sculpti- carina comb. nov. differs from Zrochomorpha species and Videna species recorded from mainland Southeast Asia by a combination of no spiral band, larger shell size, relatively narrower umbilicus, and strong radial striations with reticulated microsculptures (Mollendorff 1902; Preece et al. 2022; Inkhavilay et al. 2023). Trochomorpha benigna (Pfeiffer, 1863), T. vinhensis Thach, 2018 and 7! buotia Inkhavilay et al., 2023 are very similar to J. sculpticarina comb. nov. in terms of shell shape and size. For comparison, J. sculpticarina comb. nov. has a narrower funnel-shaped umbilicus, while 7: benigna and T: vinhensis have a wider funnel-shaped umbilicus and showing all preceding whorls (Inkhavilay et al. 2023). Compared with 7. buotia, J. sculpticari- na comb. nov. has radial striations and reticulated mi- crosculptures on shell surface, depressed shell, a strong peripheral keel, and last whorl convex below periphery, while 7! buotia has radial and spiral striations on the Shell surface, a dome-shaped shell, distinctly sharpened peripheral keel, and last whorl flattened below periphery (Inkhavilay et al. 2023). Discussion Mainland Southeast Asia harbours a taxonomically di- verse, overwhelmingly endemic fauna of limacoid snails, especially in the Helicarionoidea (e.g., Ariophantidae and Helicarionidae) and Trochomorphoidea (e.g., Dyaki- idae, Euconulidae, and Trochomorphidae). Confusion in classification and identification of these limacoid snails has happened multiple times because there is a morpho- logical convergence of shell shape; previously, most taxonomists or other researchers based their decisions only on shell morphology (Panha 1996; Hemmen and Hemmen 2001; Maassen 2001; Inkhavilay et al. 2019; Pholyotha et al. 2020, 2021a, c, 2022a, 2023c; Sutcharit et al. 2020b; Sutcharit and Panha 2021). The present study is an example of the long-standing taxonomic confusion that has existed since the works of Martens 1151 (1883) and Maassen (2001) were published. Prior to this study, J. sculpticarina comb. nov. had been assigned to either Trochomorpha or Videna in the Trochomorphidae. However, 1n this study, we have considered that general characters of J. sculpticarina comb. nov. are similar to those of Hemiplecta species in the Ariophantidae. The similarities include shell with an opened and deep um- bilicus, animal with a reduced caudal horn and no shell lobe, genitalia with an absence of gametolytic duct and the presence of long dart apparatus and short flagellum (Sutcharit and Panha 2021). The close relationship of Janbinmorpha gen. nov. and Hemiplecta is not only evident from their closely similar body features and reproductive anatomy, but also is evident from the molecular data. However, the significant differences in some genital traits and the amount of genetic variation among mitochondrial and nuclear gene sequences are indicative of the distinct lin- eages within the Ariophantidae. Our molecular phylo- genetic analysis confirms that Janbinmorpha gen. nov. is a genetically well-supported clade that is grouped together with the ariophantid genera Hemiplecta and Maelamaodiscus, but the relationships among them remain only partially resolved. However, the genitalia of Maelamaodiscus are rather distinct from Janbin- morpha gen. nov. and Hemiplecta by the presence of a long flagellum and long gametolytic duct (Sutcharit and Pholyotha 2023). Although the relationships within the limacoid snails, especially the Ariophantidae, are not resolved, Janbinmorpha gen. nov. is not grouped with the Trochomorphidae. In this study, the monophyly of the Trochomorphidae is confirmed and includes both genera Trochomorpha and Videna. Therefore, we con- clude that molecular and morphological data support J. sculpticarina comb. nov. as a member of the Ariophan- tidae instead of the Trochomorphidae. Regarding the helicarionoidean snails, we also have pointed out unresolved aspects of molecular phylogenet- ics of the mainland Southeast Asian taxa, which are cur- rently being studied and will continue as a goal moving forward. Our molecular phylogeny reveals that although the phylogenetic relationships within the Helicarionoidea are not resolved, all taxa assigned to the Helicarionidae always form a monophyletic clade. For the ariophantid lineages, despite the completely unresolved evolutionary relationships, we have found that there are at least two major clades of the Ariophantidae. The first major group includes the Indian taxa of Ariophanta, Cryptozona, Euplecta, Ratnadvipia and the Southeast Asian taxa of Megaustenia, while the second major group includes the Southeast Asian taxa of Sarika, Khasiella, Taphrenalla, Macrochlamys, Hemiplecta, Maelamaodiscus, and Jan- binmorpha gen. nov. However, understanding phyloge- netic relationships within this group is beyond the scope of this paper, and we suggest that more molecular data, especially the data of the type taxa of each genus from Asia as well as Australia and Africa, are needed to resolve the relationships within the Helicarionoidea. zse.pensoft.net L152 Acknowledgements We owe a debt of gratitude to all members of the Animal Systematics Research Unit, Chulalongkorn University for their kind help during field trips and technical support, and Ministry of Natural Resources and Environmental Conser- vation Forest Department, Myanmar and the Fauna & Flo- ra International (FFI) for providing the study material. We thank J. Ablett, F. Naggs, and T. White (NHM, London), R. Janssen, J. Sigwart, and S. Hof (SMF, Frankfurt a.M.), and T. von Rintelen (ZMB, Berlin), for allowing the authors to examine the collections and photographs. This research is funded by the NSRF via the Program Management Unit for Human Resources & Institutional Development, Research and Innovation (grant number B42G670038), Ratcha- dapiseksompotch Fund Chulalongkorn University, and the Thailand Science Research and Innovation Fund Ch- ulalongkorn University. In addition, we express our grati- tude to D.J. Anderson for grammar checking, and to anon- ymous reviewers for helpful comments on this manuscript. References American Veterinary Medical Association (2020) AVMA Guidelines for the Euthanasia of Animals: 2020 Edition. https://www.avma. org/sites/default/files/2020-01/2020-Euthanasia-Final-1-17-20.pdf [accessed 12 Feb 2020] Ayyagari VS, Sreerama K (2020) Molecular phylogeny and evolution of Pulmonata (Mollusca: Gastropoda) on the basis of mitochondrial (16S, COI) and nuclear markers (18S, 28S): an overview. 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