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| Sinocyclocheilus changlensis Liu, Mao & Yang, in Liu, Mao, Sudasinghe, Zhou, Chen, Yang & Meegaskumbura, 2025 |
ABSTRACT
The extensive limestone landscapes of southwestern China form one of the world's largest karst regions, providing ideal conditions for cavefish evolution. Within this region, Sinocyclocheilus, the most speciose cavefish genus globally, comprises 84 species adapted to dark environments. Despite the many species, the region is still poorly explored, with new species currently being added to the total. Here, using integrative taxonomic methods involving morphological and molecular analyses, we describe Sinocyclocheilus changlensis, a new troglobitic species discovered in a cave in central Guangxi, China. This species is characterized by the absence of eyes, an unpigmented and complete scaled body, and a forked, horn-like structure at the dorsal posterior edge of the head. Morphologically, S. changlensis differs from its congeners by having pelvic-fin rays that do not reach the anus when extended, 42–46 lateral line scales, and a posterior operculum margin reaching the base of the pectoral fin at vertical. Molecular phylogenetic analyses using mitochondrial markers (cytb and ND4), genetic distances, and geometric morphometric analysis further confirmed S. changlensis as a distinct species. The description of this new species contributes to the understanding of cave-dwelling fish diversity in China and underscores the importance of further exploration of stygomorphic species across this poorly explored karstic landscape.
Keywords: blindness, cavefish, Hongshui River, landmarks, molecular systematics, morphology, Sinocyclocheilus, stygomorphic
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| Sinocyclocheilus changlensis, GXU2020000041, HOLOTYPE, 137.8 mm SL. (a) Lateral view of preserved specimen; (b) dorsal view of head in preserved specimen; (c) live specimen. |
Sinocyclocheilus changlensis Liu, Mao & Yang, sp. nov.
Diagnosis: Sinocyclocheilus changlensis can be distinguished from all other congeners by the following combination of characters: eye absent (eyeless); pelvic-fin rays tip not reaching the anus when pelvic-fin rays are extended backward; having a forked horn-like structure at the dorsal posterior edge of the head; albinotic body without pigmentation; lateral line scales 42–46; posterior margin of operculum close to the base of pectoral-fin origin; a distinct hump in the predorsal profile; rostral barbel not reaching the depression after eye degeneration; maxillary barbel not reaching the posterior margin of preoperculum; pharyngeal teeth pattern 1,3,4–3,3,1; vertebrae 4 + 35–36; 11 outer rakers on the first gill arch.
Yewei Liu, Tingru Mao, Hiranya Sudasinghe, Jiajun Zhou, Rongjiao Chen, Jian Yang, Madhava Meegaskumbura. 2025. Description of A New Eyeless Cavefish Species Using Integrative Taxonomic Methods—Sinocyclocheilus changlensis (Cypriniformes, Cyprinidae), From Guangxi, China. Ecology and Evolution.15(11); e72370. DOI: doi.org/10.1002/ece3.72370 [19 November 2025]
