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| Formosania tangi Chen, Zhou, Chen & Yang, 2026 |
Abstract
For decades, populations of the suck-loach genus Formosania from the Jiulongjiang River in Fujian Province, China, have been identified as F. fascicauda, a species originally described from in a separate coastal drainage basin in Fuqing County. Employing an integrative taxonomic approach combining morphological and molecular phylogenetic analyses, we demonstrate that the Jiulongjiang River population represents a distinct species, formally described here as Formosania tangi sp. nov. It is diagnosed by a combination of characters: 13 rostral barbels arranged in two rows, a distinct straight, dark, longitudinal stripe along the lateral line, and an emarginate caudal fin. Phylogenetic analyses consistently recover it as a unique evolutionary lineage showing significant genetic divergence from true F. fascicauda, with a Kimura 2-parameter distance of 4.16%. The description of F. tangi clarifies the taxonomic status of the Jiulongjiang River population and enhances our understanding of species diversity and biogeography of Formosania in the coastal drainages of southeastern China.
Key words: Molecular phylogeny, morphology, new species, taxonomy
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| Lateral, dorsal, and ventral views of Formosania tangi sp. nov., holotype, adult, SHOU20251010601, 63.74 mm SL. |
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| Formosania tangi sp. nov. Habitat (photographed by Yong-Sheng Lin) and live appearance. (photographed by Hao-Jun Chen). |
Formosania tangi sp. nov.
Diagnosis. The new species can be distinguished from congeners by combination of following characters: rostral barbels 13, well developed, arranged in two rows (Fig. 3B) (vs one row in F. davidi, F. fasciolata, F. galericula, and F. immaculata – Fig. 3A; 12–15 rudimentary barbels in F. chenyiyui – Fig. 3C); lateral line accompanied by broad, dark, longitudinal band, margins weakly undulating or nearly straight, pale stripe between lateral line band and dark dorsal surfaces ...
Etymology. The species name honours Wen-Qiao Tang, a senior Chinese ichthyology researcher, and is derived from the latinized Chinese spelling of his family name, in recognition of his contributions to the field. We propose “Wén Qiáo Yīng Kŏu Qiū” (文乔缨口鳅) as its Chinese common name.
Yang Chen, Jia-Jun Zhou, Jing-Chen Chen, Jin-Quan Yang. 2026. Formosania tangi, A New Species of Suck-loach (Cypriniformes, Gastromyzontidae) from the Jiulongjiang River, southeastern China, with Taxonomic Notes on F. fascicauda. ZooKeys. 1273: 147-166. DOI: doi.org/10.3897/zookeys.1273.184335 [17 Mar. 2026]
