Morphological comparison of bleaks (Alburnus, Cyprinidae) from the Adriatic Basin with the Description of a new species

Abstract

The morphometric, meristic and phenotypical characters of the members of the genus Alburnus from the Adriatic Basin were analyzed on specimens from 11 localities, representing eight watersheds. The number of gill rakers, the number of lateral line scales, the number of branched anal fin rays and the coverage of the ventral keel by scales have the greatest significance in differentiating between species. Significant morphological differences exist between the Alburnus population from Lake Lugano (type locality for Alborella maxima Fatio, 1882) and all the remaining investigated populations. Alburnus from the Neretva River drainage is described as a new species and it is distinguished from other species of the genus Alburnus by the following combination of characters: 13½-15½ branched anal fin rays; 17–26 gill rakers; 40–48 lateral line scales; first anal fin ray below branched dorsal rays 6–10 or located up to one scale after the last dorsal fin ray; ventral keel exposed for at least ⅔ of a distance between the pelvic fin base and the anal aperture. The status of the Neretva River basin populations as a separate species was corroborated by genetic analyses, with p-distance between newly described species and A. arborella from the Zrmanja River 1.8–2.2%.