Hybodontiform sharks from the Late Cretaceous Alcântara Formation, São Luís Basin, Northeast Brazil

This study describes new hybodontiform remains from the Cenomanian Alcântara Formation, São Luís Basin, northeastern Brazil. The fossil material includes cephalic spines, dorsal fin spines, and oral teeth attributed to three hybodontiform families: Distobatidae, Hybodontidae and Lonchidiidae. The Distobatidae record is substantiated by both the newly described Distobatus nutiae identified in this study and the previously reported Aegyptobatus cf. kuehnei from the region. Diagnostic cephalic spine morphologies (‘T-shaped’ and ‘arrow-shaped’) support the attribution to Hybodontidae and Lonchidiidae, respectively. The occurrence of Distobatidae in the Alcântara Formation, together with records from other Cretaceous deposits in northeastern Brazil and North Africa, suggests possible faunal affinities among freshwater and marginal marine hybodontiforms of northern Gondwana. These findings provide new insights into the paleobiogeographic links between South America and Africa during the early stages of South Atlantic opening.