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| Janbinmorpha sculpticarina (Martens, 1883), comb. nov., Janbinmorpha Pholyotha & Panha, gen. nov. in Pholyotha, Sutcharit, Panha et Tongkerd, 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 “Trochomorpha” 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 nuclear 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
Taxonomy and systematics
Superfamily Helicarionoidea Bourguignat, 1877
Family Ariophantidae Godwin-Austen, 1883
Subfamily Ariophantinae Godwin-Austen, 1883
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| 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; F. Specimen from Phang-nga Province: CUMZ 15151 using for SEM imaging. |
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| Janbinmorpha sculpticarina (Martens, 1883), comb. nov. Map of the Malay Peninsula in southern Thailand and the southernmost tip of Myanmar showing the sampling sites. Localities where the living specimens were collected are indicated by numbers on map, not to scale. |
Janbinmorpha Pholyotha & Panha, gen. nov.
Type species: Trochomorpha sculpticarina Martens, 1883; here designated.
Diagnosis: Shell dextral, umbilicated, depressed, lenticular, ribbed, with keeled last whorl. Animal with three dorsal lobes; foot tripartite; caudal foss present; caudal horn very reduced. Genitalia having epiphallic caecum, flagellum and dart apparatus; proximal epiphallus encircled with thickened muscular epiphallic sheath; gametolytic organ without duct and gametolytic sac consisting of two bulbs. Radula with tricuspid central tooth; unicuspid or bicuspid lateral teeth; unicuspid marginal teeth.
Distribution: Currently known only from the Malay Peninsula.
Etymology: The name combines “Janbin” in reference to the shape of an unidentified flying object (UFO) in the Thai language, and similar to the shell shape of this new genus, and “morpha” in reference to the similarity of shell morphology between this new genus and the genus Trochomorpha.
Janbinmorpha sculpticarina (Martens, 1883), comb. nov.
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| 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 Euconulidae; E. Trochomorpha sp.2 in the Trochomorphidae; F. Pseudoplecta bijuga (Stoliczka, 1873) in the Dyakiidae. |
Arthit Pholyotha, Chirasak Sutcharit, Somsak Panha and Piyoros Tongkerd. 2024. Reassessment and Phylogenetic Position of the overlooked limacoid Land Snail Trochomorpha sculpticarina Martens, 1883 (Eupulmonata, Ariophantidae), with the Description of A New Genus. Zoosystematics and Evolution. 100(3): 1135-1154. DOI: doi.org/10.3897/zse.100.129455