Caracterização anatômica de Rhinoptera provenientes da costa brasileira

Abstract

The Batoidea form one of the most well represented groups of Elasmobranchii in the Brazilian coast, presenting numerous species distributed in the following orders: Pristiformes, Torpediniformes, Rhinobatiformes, Rajiformes and Myliobatiformes. Although very abundant and with some of the orders relatively well studied from the taxonomic point of view, some taxa remain weekly known. The main objective of the present study is to compare specimens of two nominal species found in the Brazilian coast, <i>Rhinoptera brasilienses</i> Müller, 1836 and <i>Rhinoptera bonasus</i> (Mitchill, 1815), using morphological and molecular data. Our morphological results validate the existence of two species that differ mainly by the number and shape of teeth, where <i>R. bonasus</i> has 6 to 8 rows of teeth, with the central row approximately twice as large as the adjacent rows and <i>R. brasilienses</i> possesses of 8 to 10 rows being the central row of similar size of the parallel rows. The results of our molecular study, obtained from the sequencing of the coding part of the 16S mitochondrial gene, are different from the morphological result, pointing to the existence of a single species. Due to the contradiction between the morphological and molecular data, a more detailed study is necessary, preferably including all the other representatives of the group, thus validating the species and confirming the characters that distinguish them.