Utilização de técnicas multivariadas e de morfometria geométrica na discriminação de espécies do gênero Rhinobatos (Família Rhinobatidae) do Nordeste do Brasil

Abstract

The guitarfish Rhinobatos cf percelens is a marine ray inhabiting shallow coastal waters in southern hemisphere. The analyzed sample was collected at Caiçara do Norte, off Rio Grande do Norte state (Brazil). Traditional techniques and geometric morphometry were used aiming at identifying the specific status of the exploited species along the Brazilian Northeast coast. For that, comparisons between R. percellens and R. lentiginosus were carried out by means of data obtained from the literature and data from paratypes of both species provided by the Museu Oceanográfico da Universidade do Vale do Itajaí - MOVI. The knowledge of the specific status of fishes composing commercial catches is essential for allocating them in their proper stock units, so that stock assessments can be conducted as well as management measures undertaken. Thus, were used as approach the analysis morphometric, through techniques of image processing, analysis multivariate and geometric morphometric, using for comparison the described pattern widely accepted for each species. Individual images were digitalized through a camera and stored in files of image jpeg. The coordinates of landmarks and pseudo-landmarks definedover the dorsal part of the animal were obtained and matrix of data was submitted to the mentioned techniques allowing comparisons of the form variations among specimens. Results obtained pointed out two groups, consisting the first at dark coloration specimens with numerous white spots, while the second was made up of individuals brown coloration with or without spots.