Morphological divergence of goatfishes (genus Mullus, Mullidae, Perciformes) of the black and Mediterranean Seas and the problem of assessment of their taxonomic relationships

We conducted a comparative analysis of the morphological characters used previously for the description and subsequent identification of the Black Sea subspecies of red mullet Mullus barbatus based on the materials of the collections of the Zoological Museum of Moscow State University and the Zoological Institute of the Russian Academy of Sciences. The average value of the ratio between the snout length and head depth at the level of the middle of the eye is the only morphological character that is valuable for the separation of all studied local populations of the Black Sea from the populations from the Mediterranean Sea. Divergence by this character does not reach a formal subspecies level (CD = 1.28), and the level of genetic divergence between the Mediterranean and Black Sea goatfishes remains unclear. Based on this study, a sub-species level of the Black Sea red mullet is not supported.