Resolving taxonomic uncertainty in vulnerable elasmobranchs : are the Madeira skate (Raja maderensis) and the thornback ray (Raja clavata) distinct species?

Ball, R E, Serra-Pereira, B, Ellis, J, Genner, M J, Iglesias, S, Johnson, A F, Jones, C S, Leslie, R, Lewis, J, Mariani, S, Menezes, G, Neat, F, Noble, L R, Sims, D W & Griffiths, A M 2016, 'Resolving taxonomic uncertainty in vulnerable elasmobranchs : are the Madeira skate (Raja maderensis) and the thornback ray (Raja clavata) distinct species?', Conservation Genetics, vol. 17, no. 3, pp. 565-576. https://doi.org/10.1007/s10592-015-0806-1