A new Myliobatid species from Argentine waters? Morphological and DNA Barcoding approaches

DÍAZ DE ASTARLOA, J. M.; RUOCCO, N. L.; LUCIFORA, L.; MABRAGAÑA E.; DELPIANI, S. M.

Adelaide

Congreso; Fourth International Barcode of Life Conference; 2011

Discriminating and identifying species solely based on morphological traits has always been challenging, because traditional approaches are time consuming, labor intensive and require specialized experts. Moreover, diagnoses and descriptions of species have almost universally been based on morphological data, being traditional taxonomy largely based on discontinuous patterns of morphological variation. Two species of Myliobatis, the Southern eagle ray M. goodei Garman and the Bullnose eagle ray M. freminvilli Lesueur have long been recognized to be occurring from coastal Argentinean waters. Several unusual specimens of Mylibatidae have been recently collected from Buenos Aires Province coast of Argentina. Although clearly belonging to the genus Myliobatis, because of the disk broad with long sharply pointed wings and projecting snout, tail very long and thin, smaller dorsal fin set farther back on tail, well beyond the pelvic fins, the specimens were distinct from all congeners in several characters. By comparing morphometric, meristic features and clasper morphology, specimens referred as Southern eagle ray and originally regarded as M. goodei were shown to be a discrete species as distinguished from both the Southern eagle ray and Bullnose eagle ray. In order to corroborate these findings cytochrome c oxidase I (COI) sequence data were obtained from the new specimens and compared with those of its congeners. As expected, DNA barcoding support previous finding showing a congeneric sequence divergence higher than 6%. Therefore combining both, traditional taxonomy and DNA Barcoding, a new Eagle ray species from the Southwest Atlantic Ocean was discovered.