The utility of urohial shape in the discrimination of Pisces: Mugilidae species and local population

ABSTRACT: Background. The exploration of new structures allowing species identification is relevant for fisheries science since it permits to be managed according to their specific characteristics. The urohial is a specific structure of bony fish. The Pisces: Mugilidae is a family with very conserved morphology, so finding a structure useful to discriminate species and/or populations is a pending task. Goals. Thus, the objective is to determine the usefulness of the urohial bone shape on its lateral, dorsal and ventral view in species discrimination: Mugil cephalus and M. curema and in location discrimination, two from the Gulf of Mexico and one for the Mexican Pacific. Methods. Urohial shape was analyzed using the Procrustes method were the relative warps were submitted to discriminant analyzes and MANCOVA in order to detect differences in lateral, dorsal and shape among species and localities (α = 0.05 p <0.05). Results. Cross-validation percentages of classification percentages by species were 86.6, 96.5 and 95.1% for lateral, dorsal and ventral views, respectively where the dorsal view in addition to being the one that showed the highest percentage of classification was less influenced by size. Among locations for M. curema percentage of classification were 65.9, 54.9, and 60.4%, respectively, and for M. cephalus were 66.7, 49.0 and 56.9%, respectively. Size did not influence the uriohial shape, except in the ventral view for M. cephalus. Conclusions. The urohial bone was useful for the discrimination of species, particularly in its dorsal view, while it was less suitable for discriminating between localities.