Teeth of Skates in the Southwest Atlantic

FIGUEROA DANIEL E.; RIVERA PAULA; BELLEGGIA MAURO; DELPIANI GABRIELA; SHIMABUKURO VALERIA; SCENNA LORENA; BARBINI SANTIAGO; BOVCON NELSON

Portland

Congreso; Joint Meeting of Ichthyologists and Herpetologists; 2009

American Elasmobranch Society

Dentition in skates are used not only for feeding but also for reproduction, both are influentialfactors on tooth morphology. Despite teeth of elasmobranchs are very abundant skeletonelements in fossil records, the study of dentition of skates has not reached the developmentachieved in sharks. Southwest Atlantic appears to be a great radiation center of skates, probablydue to its large continental shelf, and its transitional waters. Fossil teeth of skates in this regionwere recorded since the Cretaceous. A total of 23 species of skates inhabit Argentineancontinental shelf. Their feeding habits are very diverse. Adult individuals of some species havespecialized diet in fishes and large sharp tooth cusps, showing no sexual dimorphism (e.g.Bathyraja brachyurops and Bathyraja magellanica). On the other hand, some species have aspecialized diet in polychaetes (e.g. Bathyraja albomaculata and Bathyraja macloviana) andevidence a very clear sexual dimorphism, with males presenting larger and sharper tooth cuspsthan females. In both groups tooth rows of males are well spaced which allows their properdifferentiation. An extreme case is Bathyraja multispinis, with teeth without cusps and aquincunx pattern, its diet is based on crabs. In Amblyraja doellojuradoi have appeared curiousdental anomalies, such as bicuspid teeth and row duplication. Given the fact that the dentitionof many species has not been studied yet and considerable variations in tooth morphology wereshown between the species of skates studied, future research is necessary for intra andinterspecific comparations.