Morphological and biometric comparison of the scales of the barbels (Barbus cuvier) of Spain.

The scales of 386 specimens of the eight species of the genus Barbus present in Spain (B. bocagei, B. comiza, B. graellsii, B. guiraonis, B. haasi, B. meridionalis, B. microcephalus, and B. sclateri) were studied. Six scales were extracted from each specimen, measurements taken, and the number of radii noted. Indices were obtained from these data. Statistical analysis allowed two groups to be established: 1) B. meridionalis and B. haasi, living in the upper stretches of rivers and distributed in the north of Spain; and 2) the remaining species. Within both groups a latitudinal gradation in the elongation of the scales and in the proportion of radii of the lateral fields was observed.