Resolving a 165‐year taxonomic conundrum in African galaxiids (Teleostei: Galaxiidae): Reinstatement of Agalaxis Scott, 1936, revalidation of A. punctifer and A. dubius, and description of a new species

Abstract The Cape galaxias, formerly treated as the single African representative of the family Galaxiidae under the name Galaxias zebratus (Castelnau, 1861), has long masked substantial hidden diversity. We consolidated all available molecular data and generated additional sequences to fill sampling gaps, providing the most comprehensive assessment of historically isolated lineages within this complex to date. Analysis of mitochondrial cyt b and COI sequences identified 15 genetically distinct lineages, most with restricted geographic ranges. Previous phylogenetic studies demonstrated that the African galaxiids are not closely related to Galaxias truttaceus Valenciennes, 1846, the type species of Galaxias , suggesting they may be misclassified. Detailed morphological and osteological examinations identified consistent diagnostic characters separating the Cape galaxiids from Galaxias and other galaxiid genera. Molecular and morphological evidence supports reinstatement of the genus Agalaxis Scott, 1936, for the African galaxiids. We further revalidate Agalaxis punctifer (Castelnau, 1861) and A. dubius (Gilchrist & Thompson, 1917), describe A. peninsulae sp. nov. and designate a neotype for and redescribe A. zebratus s.s. By resolving the application of available names, we establish a taxonomic framework for resolving the remaining undescribed diversity and recognise the Cape galaxiids as a diverse endemic radiation within the Cape Fold Ecoregion.