Abstract
Petroleuciscus ninae sp. nov. is described from the Büyük Menderes River drainage. The new species is distinguished by having a black lateral stripe from head to base of caudal fin, stripe distinct anteriorly and posteriorly, wider than eye diameter; numerous black pigments on anal‐fin rays; body depth at dorsal‐fin origin 27–30% standard length ( L S ); head width at posterior margin of eye 16–19% L S ; and eye diameter smaller than snout length. Petroleuciscus ninae is also distinguished from other species in adjacent waters by having six fixed diagnostic nucleotide substitutions in the mitochondrial DNA coI barcode region.