A prelude to the molecular systematics and diversity of Labeobarbus (Teleostei, Cyprinidae) in KwaZulu-Natal, South Africa, with the description of a new large chiselmouth.

Labeobarbus, a genus of large, hexaploid cyprinids, is endemic to the African continent. With 121 valid species, it ranks among the most species-rich genera within both the African cyprinids and African freshwater fishes. The southern African region has 11 species that are all endemic; however, the phylogenetic and taxonomic diversity of these species is poorly understood. Insights from published data from studies that focused on a relatively small subset of targeted species and localities suggest that species diversity within this genus has not been fully documented. This study presents a preliminary phylogenetic analysis of Labeobarbus natalensis based on mitochondrial DNA (mtDNA) cytochrome c oxidase subunit I (COI) sequences of topotypic samples of this species and its junior synonyms from its distribution range in KwaZulu-Natal (KZN), South Africa. We uncovered the existence of at least five genetically distinct and geographically isolated lineages within L. natalensis s.l., as well as a highly morphologically divergent and genetically differentiated chiselmouth from the Mzimkulu River system that we describe as a new species, Labeobarbus kylei sp. nov. This species is distinguished by unique morphological features, including a broader head and mouth, and a well-defined cutting edge on the lower lip. Preliminary assessment indicates that L. kylei sp. nov., which is currently only known from the Mzimkulu River system, is critically endangered due to its narrow distribution range and small population size.