Anatomical Investigations of the New Zealand Skates Bathyraja asperula and B. spinifera, with an Evaluation of Their Classification within the Rajoidei (Chondrichthyes)

Abstract

Neurocranium, scapulocoracoids, and claspers of Bathyraja asperula, and the former two structures of B. spinifera are described and compared with those of all other supraspecific taxa (genera and subgenera) of Rajoidei. Comparisons revealed that B. asperula and B. spinifera share apomorphic character states in the above and other structures with Raja (Malacoraja), Pavoraja, Neoraja and Gurgesiella, and a higher level classification revealed that these taxa form a monophyletic group. The above taxa are placed in the Tribe Pavorajini, newly erected, of Rajidae. Cladistic analysis within Pavorajini, based on 38 characters, indicates that Raja (Malacoraja) is the sister group of the other taxa, that Neoraja (Neoraja) is the sister group of the remaining taxa, that Pavoraja and B. asperula + B. spinifera are sister groups that Neoraja (Fenestraja) and Gurgesiella are sister groups, and that Pavoraja + B. asperula + B. spinifera and Neoraja (Fenestraja) + Gurgesiella are sister groups. These findings necessitate the following taxonomic changes: Raja (Malacoraja) and Neoraja are elevated to genera. Pavoraja consists of P. (Pavoraja) and Subgenus A, the latter is proposed for B. asperula and B. spinifera. Gurgesiella consists of G. (Gurgesiella) and G. (Fenestraja). Diagnostic characters are given for Pavorajini and the six genera and subgenera.