A comparative analysis of the scapulocoracoid and cervico-thoracic synarcual cartilage of juvenile specimens of Rhinoptera brasiliensis Müller & Henle, 1841 and R. bonasus (Mitchill, 1815) was accomplished, in order to identify specific, individual and ontogenetic differences. In the scapulocoracoid, the scapular foramen and the posterodorsal fenestra is larger in R. brasiliensis. The anterior fenestra bridge is thicker and the metacondyle is thinner and longer in R. bonasus. This species also possesses a larger re-entrance between the mesocondyle and the metacondyle, as well as in the fitting region of'the synarcual cartilage, placed close to the scapular process. The individual differences are: posteroventral fenestra with variable diameter... |