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| Semisulcospira egretta Y.-Z. Meng, in Xu, Meng, Zeng, Wang, Zhong, Yang, Zhou et Glasby, 2025. |
Abstract
During our investigation of the diversity and phylogeny of the family Semisulcospiridae in China, we have found a presumed new species in mountain streams of Xiamen, Fujian Province on both morphology and molecular evidence. This new species, Semisulcospira egretta sp. nov., is characterized by its thin and smooth shell, retaining about 0.5 mm long embryonic shells in its brood pouch, and by distinctive features of its radular morphology. Phylogenetic analyses of partial sequences of the mitochondrial markers 16S ribosomal RNA (16S) and cytochrome c oxidase subunit I (COI) and complete sequences of the nuclear ribosomal internal transcribed spacer (ITS, including internal transcribed spacer 1, 5.8S ribosomal RNA gene, and internal transcribed spacer 2) supported the distinctiveness of S. egretta sp. nov. from other Semisulcospira species. These analyses consistently placed S. egretta sp. nov. in Semisulcospira confirming its monophyly. Phylogenetic analyses based on just COI and 16S exhibited low resolution rendering the phylogenetic position of the new species within the genus uncertain. In contrast, phylogenetic tree analyses of complete mitochondrial genomes, which include 13 protein-coding genes (PCGs), were better resolved. However, the mitogenome dataset included a more restricted sampling of taxa (16), impeding a detailed exploration of the phylogenetic position of the new species. To address this deficit, we provide seven complete mitochondrial genomes for S. egretta sp. nov., obtained using the genome skimming sequencing method. This study contributes important molecular and genomic data, aiding in the understanding of semisulcospirid phylogeny, and highlights the need for further taxonomic sampling and phylogenomic methods to resolve the evolutionary relationships within Semisulcospiridae.
Key Words: 16S rRNA, COI, mitogenome, phylogenetic analysis, semisulcospirid gastropods
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| The habitat and sampling localities of Semisulcospira egretta sp. nov. in Xiamen City, Fujian Province, China. A. Type locality, ..., in Haicang District; B. locality, ..., in Tong’ an District; C. A simplified map of Xiamen, locality A and B are marked with red points; D. A living specimen of S. egretta sp. nov. All photos are taken by Yuan-Zheng Meng. |
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| Semisulcospira egretta sp. nov. and congeners. A-F, Semisulcospira egretta sp. nov. A. Holotype, with operculum, XMU_DYY_TZS_003; B. Paratype 6, XMU_DYY_TZS_002; C. Paratype 34, XMU_DYY_XMA15; D. Paratype 32, XMU_DYY_XMA13; E. XMU_DYY_XMB01; F. XMU_DYY_XMC01; G–J. S. kurodai; G. ZMB 114713a; H. ZMB 114713b; I. ZMB 114754a; J. ZMB 114754b; K–M. S. libertina, syntypes of Melania japonica, NHMUK ZOO 20210249; N. S. pleuroceroides, lectotype of Melania pleurocerides, MNHN-IM-2000-21289; O. S. guilinensis, holotype, NNUH20240901; P. S. tigra, holotype, NNUH20240101; Q. S. sangpuensis, holotype, NNUH20241001. A–F. Photographed by Yuan-Zheng Meng; G–J. from Köhler (2016); O–Q. from He et al. (2024). |
Semisulcospira egretta Y.-Z. Meng, sp. nov.
Diagnosis: Viviparous. Shell medium size, up to 25 mm, yellow-brownish, elongate, smooth, thin, comprising seven to nine whorls. Pregnant female bears about 150 embryos. Embryonic shell about 0.5 mm in length. Only known in Xiamen, Fujian Province, China.
Etymology: The word egretta means “egret” in Latin. Egret is the city bird of Xiamen, which also suggests the type locality of this species. We suggest the Chinese common name as “白鹭短沟蜷”.
Yi-Bin Xu, Yuan-Zheng Meng, Sheng Zeng, Hang-Jun Wang, Shen Zhong, De-Yuan Yang, Xi-Ping Zhou and Christopher J. Glasby. 2025. A New Species of Semisulcospira O. Boettger, 1886 (Gastropoda, Cerithoidea, Semisulcospiridae) from Fujian, China with mitochondrial genome and its phylogenetic implications. Zoosystematics and Evolution. 101(1): 17-34. DOI: doi.org/10.3897/zse.101.136882
