Luciobarbus lydianus and L. kottelati, two synonyms of L. graecus (Teleostei: Cyprinidae).

The Aegean Luciobarbus graecus, L. lydianus, and L. kottelati were described based on morphological characters. However, re-examination of fresh material from the three species revealed greater intraspecific variability in morphological character states, and wider overlaps in all postulated diagnostic traits than initially documented. Consequently, it is not possible to identify and distinguish these three species based solely on morphological characteristics. As they also share identical COI barcode sequences, these species are now considered conspecifics, and L. lydianus and L. kottelati are treated as junior synonyms of L. graecus. The distribution of L. graecus remains a biogeographical puzzle, and it cannot be excluded that this could be partly human-mediated. Population-level genomic studies, particularly those focusing on phylogeography and population genetics, may help clarify mechanisms underlying contemporary distribution of this species.