Caracterización molecular de rayas simpátricas de los géneros Dipturus y Zearaja en el mar argentino por DNA Barcode

Skates of the genera Dipturus and Zearaja present a particular challenge for fishery management and conservation, since they have been subject to intense exploitation in the last years. In the Argentine Sea, these genera are represented by D. leptocauda, D. trachyderma, D. argentinensis and Z. chilensis. These last three are sympatric species since they overlap in depth and geographic distribution. Their behavioral habits and the morphological similarity make these species, especially in juvenile stages, difficult to identify. The use of the mitochondrial gene Cytochrome C Oxidase I (COI) as a DNA Barcode (genetic barcode), is a useful molecular tool to identify morphologically similar species. In this work, we used the DNA Barcode to identify specimens of Z. chilensis that presented a different thorny pattern in their dorsal side and tail instead of the common pattern found in that species. Also, we compared the DNA Barcode with other sympatric skates’ species to obtain a molecular characterization of the Dipturus and Zearaja species from the Argentine Sea. The DNA Barcode was obtained from 23 individuals collected along the Argentine continental shelf. The specimens were classified as D. argentinesis, Z. chilensis and Z. chilensis with a distinct different spinal pattern (specimens ZSP). The specimens were identified at species level by comparing their barcodes with reference sequences of specimens from the Pacific and Atlantic ocean in Barcode of Life Data System (BOLD), and also by the intra and interspecific Kimura two-parameter (K2P) distance. The ZSP individuals were identified as Z. chilensis with more than 99% of similarity, and they had a K2P distance of 0.24% with the reference sequences collected in the Argentine Sea. The K2P distance between D. argentinensis and Z. chilensis was 3.1%, this value could suggest that both species are the same Genus Zearaja. We found that the specimens’ reference sequences of Z. chilensis from the Pacific had a high divergence (3.46%) from the Z. chilensis of the Argentine Sea, which would indicate two different species, suggesting that the Argentine form should be called Z. flavirostris (Philippi, 1892). From this work, we conclude that the DNA Barcode is a useful and efficient molecular marker to identify skates’ species. The obtained genetic distance data contributes to the characterization of these sympatric species from the Argentine Sea and is a useful tool as a reference parameter for the differentiation of the species.