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| Siamopotaxis Pholyotha, gen. nov. Siamopotaxis principalis Pholyotha, sp. nov. Siamopotaxis thailandensis Pholyotha, sp. nov. in Pholyotha, Tongkerd, Panha et Sutcharit, 2025. |
Abstract
The new helicarionoidean land snail genus Siamopotaxis Pholyotha, gen. nov. is described for two new species, Siamopotaxis principalis Pholyotha, sp. nov. and Siamopotaxis thailandensis Pholyotha, sp. nov., both from Thailand. The new genus is characterised by a medium-sized, globose, high-spired, cream-coloured shell, with one or two supraperipheral bands, a rounded last whorl, a short epiphallic caecum, an elongated dart apparatus, and many radular teeth with pectiniform cusps. Siamopotaxis principalis sp. nov. differs from S. thailandensis sp. nov. by the presence of one spiral band, whereas the latter species has two spiral bands. A DNA sequence analysis of mitochondrial COI and 16S DNA, and nuclear 28S DNA gene fragments, supports the systematic placement of these new taxa and confirms that Siamopotaxis gen. nov. as a distinct clade within the Helicarionidae.
Keywords: Diversity, Endemic, Indochina, Land snail, Limestone, Taxonomy
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| A–D Siamopotaxis principalis sp. nov., A holotype CUMZ 15186, and B–D paratypesCUMZ 15257 from the type locality. E, F Siamopotaxis thailandensis sp. nov., E holotype CUMZ 15116 and F paratype CUMZ 15117 from the type locality |
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| Photographs of living snails. A, B Siamopotaxis principalis sp. nov., paratype CUMZ 15257, A right side, B left side. C, D Siamopotaxis thailandensis sp. nov., C right side of paratype CUMZ 15117, D left side of paratype CUMZ 14924. |
หอยหางดิ้นเจ้าฟ้า Siamopotaxis principalis
Arthit Pholyotha, Piyoros Tongkerd, Somsak Panha and Chirasak Sutcharit. 2025. Discovery of a New Helicarionoidean Land Snail Genus Siamopotaxis gen. nov. (Eupulmonata: Helicarionidae) from Thailand Based on Molecular Phylogenetic and Morphological Evidence. Tropical Natural History. Suppl. 8; 121-139. DOI: doi.org/10.58837/tnh.25.8.267115 [2025-10-14]
