A New Species of Cyprinid Genus Opsariichthys (Teleostei: Cyprinidae) from the Pearl River, Southern China †

A new cyprinid fish, Opsariichthys rubriventris sp. nov., is described from the Xizhijiang River, a tributary of the Pearl River basin in Huizhou City, Guangdong Province, southern China. The species is distinguished from all other congeners by the following combination of characters: predorsal scales 13–14; lower jaw projecting slightly beyond upper jaw; cheek with two mainly longitudinal rows of tubercles; and lower jaw, belly, pectoral fin, and anterior margin of anal fin in adult males being reddish-orange. The principal component analysis result of the morphological data indicated that O. rubriventris sp. nov. could be clearly distinguished fromfour other congeners. The phylogenetic analysis conducted in this study, utilizing both Maximum Likelihood (ML) and Bayesian Inference (BI) methods, supported the monophyly of the novel species O. rubriventris sp. nov. at the species level. Additionally, the genetic distance analysis revealed that O. rubriventris sp. nov. exhibits a genetic distance ranging from 0.14 to 0.16 with its congeneric species, further affirming its taxonomic status.