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

Abstract

Sophina is a poorly known and neglected genus due to the inaccessibility of the Salween Basin, Southern Myanmar. Taxonomic status, distribution, and phylogeny are being revised based on an integrative analysis of genitalia, radula, and molecular data. Morphological variation in shells and genitalia, together with a phylogenetic tree from concatenated data of mitochondrial and nuclear genes, revealed the existence of ten species/subspecies. Penial morphology and genetic divergence were generally consistent and useful in delimiting species, while shell characters showed little overall taxonomic utility in some species. Taxonomic placement of the previous subspecies “bensoni” shows clear distinction in both genitalia and molecular evidence, and is currently recognized as a distinct species. The nominal species “S. schistostelis” and “S. calias” possess similar genitalia and shell morphology, and molecular evidence suggested that they are sister taxa representing geographically isolated populations. Four new species are additionally described herein as S. furfuracea n. sp., S. pisinna n. sp., S. salweenica n. sp., and S. tonywhitteni n. sp. based on both morphology and molecular evidence. Phylogenetic analyses supported monophyly of Sophina, and further a split into two principal clades. These two clades showed little difference in genitalia, but more clear differences in the umbilical area and allopatric distribution in upper and lower reaches of the Gyaing River. High genetic divergence was revealed and this coincided with remarkable degree of endemism and localization with a pattern of one outcrop for one lineage. These data highlight the importance of the Salween Basin's karst ecosystems as an evolutionary and endemic biodiversity hotspot, and indicate that a focus on conservation and management in this area is urgently required.

Systematic revision of the limestone karst-restricted land snail genus Aenigmatoconcha (Eupulmonata: Helicarionidae), with description of a new species

“…Although the phylogenetic relationships among Aenigmatoconcha, Sophina and Chalepotaxis remain unresolved, the genital characters of both groups of Aenigmatoconcha were clearly distinct from Sophina and Chalepotaxis. In the phylogenetic tree of the 28S gene, moreover, these three genera were confirmed as different genera, but the systematic position of two Aenigmatoconcha species (A. clivicola and A. sumonthai) is unresolved (Sutcharit et al 2020a). Further research should include on more genes and more taxa of the Southeast Asian helicarionoids to better understand the phylogenetic relationships and morphological evolution of these groups.…”

“…The greatest similarity in shell characters occurred in Sophina and Chalepotaxis, but their genitalia are obviously different. The distinctive characters between Aenigmatoconcha and Chalepotaxis have been reported (Tumpeesuwan & Tumpeesuwan 2017;Sutcharit et al 2020a). However, Tumpeesuwan and Tumpeesuwan (2017) did not report the presence of a "penial sheath" and a "flagellum" in A. clivicola (the type species).…”

“…In the descriptions, the terminology and abbreviations used here follow those of Tumpeesuwan & Tumpeesuwan (2017), Pholyotha et al (2018), andSutcharit et al (2020a).…”

“…The final sequence dataset contained sequences of 22 Aenigmatoconcha specimens together with five helicarionid specimens (one sequence of Chalepotaxis Ancey, 1887 and four sequences of Sophina Benson, 1859) included as related taxa based on a molecular phylogeny of some Asian Helicarionidae (Sutcharit et al 2020a). In addition, two specimens of Sarika Godwin-Austen, 1907 from the family Ariophantidae were used to root the trees.…”

“…Generally, helicarionoid snails tend to have a diverse shell form but conserved reproductive organs and mantle lobes. These conserved characters appear to be systematically informative following integrative taxonomic approaches, such as in the Southeast Asian ariophantids (Pholyotha et al 2020b(Pholyotha et al , 2021Sutcharit et al 2020b) and helicarionids (Páll-Gergely et al 2016;Sutcharit et al 2020a), and in the Australian helicarionids (Hyman & Ponder 2010;Hyman & Köhler 2018.…”