On the sexual dimorphism of stone loach Barbatula barbatula (Balitoridae)

Sexual dimorphism of stone loach Barbatula barbatula (Linnaeus, 1758) was s tudied in three samples taken from the Vah River basin (Danube drainage) in different seasons to see if it varied between spawning and post-spawning. There were thirty nine morphometric characters examined during the course o f this study, of which six were found to be significantly different between males and females (pectoral (P) and ventral fin length, body width, dorsal fin depth, urogenital papilla length, and anus-anal fin distance). Additio nally, there was sexual dimorphism in the shape of P, position of the longe st ray of P, and type of intestinal loop, urogenital papilla and coloration . An important character found to unequivocally distinguish among the sexes was the presence, distribution and shape of epithelial tubercles. They cov ered the whole body of both sexes throughout the year, but during spawning, the adult males also had true nuptial tubercles developed on the inner sid e of P, which were absent in females.