Integrated molecular and morphological evidence reveals a new Rhodeus species (Cyprinidae: Acheilognathidae) from the Turkish Aegean basin, with a redescription of Rhodeus meridionalis

Rhodeus tugbae new sp. is described from some streams and rivers on the Turkish Aegean Sea coast. The new species is distinguished by a slightly sub‐inferior mouth, a sharped predorsal keel, a body strongly compressed laterally and 3–4 scale rows between the anal‐fin origin and the lateral series. This study contributes to understanding biodiversity and endemism in the freshwater ecosystems of the Aegean region. Rhodeus tugbae was compared to R. amarus and R. meridionalis , distributed in adjacent basin, using principal component analysis (PCA), and the results confirmed that R. tugbae differs from R. amarus and R. meridionalis . R. tugbae sp. nov. differed from its most closely related congener, R. meridionalis , by 14 diagnostic nucleotide substitution sites based on mitochondrial DNA (mtDNA) cyt b sequences. A revised description of R. meridionalis is also included due to the limited diagnostic features in the original description.