A possible occurrence of Diodontidae (Teleostei, Tetraodontiformes) in the Upper Cretaceous of the Paraíba Basin, northeastern Brazil

The members of the family Diodontidae are popularly known as porcupinefishes. They possess a long temporal range, extending from Eocene to Holocene. The occurrences of the family in the Brazilian strata are very scarce, being recorded the presence of the genus Diodon in the Miocene of the Pirabas Basin. Until now, only three families of Tetraodontiformes were reported from the Upper Cretaceous (i.e., Cretatriacanthidae, Plectocretacicidae, and Protriacanthidae). In this paper, we point out the oldest Brazilian record of Diodontidae, attributed possibly to the Gramame Formation, Upper Cretaceous (Maastrichtian) of the Paraíba Basin, northeastern Brazil. This lithostratigraphical unit includes diversified and abundant fossiliferous assemblages, including palynomorphs, microfossils, invertebrates (e.g., corals, annelids, crustaceans, mollusks, bryozoans, echinoids) and vertebrates (e.g., fishes, turtles, plesiosaurs, mosasaurs, crocodilians, pterosaurs), as well as ichnofossils. The taxon is represented by a complete upper dental plate, measuring 14.5 mm in length and 18.5 mm in width. It is associated to part of the premaxilla, which bears numerous small and individual teeth fused to its margin. The material was assigned to Diodontidae by the comparison with its extant members.