Teeth of skates in the Southwest Atlantic

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

Portland, Oregon

Congreso; Joint Meeting of Ichthyologists and Herpetologists.; 2009

American Society of Ichthyologists and Herpetologists

Skate`s teeth are used not only for feeding but also for reproduction, both are influential factors on tooth morphology. Despite teeth of elasmobranchs are very abundant skeleton elements in fossil records, the study of dentition of skates has not reached the development achieved in sharks. Southwest Atlantic appears to be a great radiation center of skates, probably due to its large continental shelf, and its transitional waters. Fossil teeth of skates in this region were recorded since the Cretaceous. A total of 23 species of skates inhabit Argentinean continental shelf. Their feeding habits are very diverse. Adult individuals of some species have specialized diet in fishes and large sharp tooth cusps, showing no sexual dimorphism (e.g. Bathyraja brachyurops y Bathyraja magellanica). On the other hand, some species have a specialized diet in polychaetes (e.g. Bathyraja albomaculata y Bathyraja macloviana) and evidence a very clear sexual dimorphism, with males presenting larger and sharper tooth cusps than females. In both groups tooth rows of males are well spaced which allows their proper differentiation. An extreme case is Bathyraja multispinis, with teeth without cusps and a quincunx pattern, its diet is based on crabs. In Amblyraja doellojuradoi have appeared curious dental anomalies, such as bicuspid teeth and row duplication. Given the fact that the dentition of many species has not been studied yet and considerable variations in tooth morphology were shown between the species of skates studied, future research is necessary for intra and interspecific comparations.