Crocodyliform diversity of the Açu Formation (Albian–Cenomanian), Potiguar Basin, Brazil: geographical distribution and palaeobiological implications

Isolated archosaur teeth are particularly abundant in Cretaceous deposits from western Gondwana (northern South America and North Africa), mainly from dinosaur, pterosaur and crocodyliform individuals. The Açu Formation (Albian–Cenomanian) of the Potiguar Basin preserves a diverse vertebrate fauna: fishes, crocodyliforms, sauropod and theropod dinosaurs, and testudines. We describe nine crocodyliform teeth from the Açu Formation (Potiguar Basin), all relatively well‐preserved, separated into four morphotypes. Three groups of crocodyliforms are recognized as new to the basin: Itasuchidae, Candidodontidae and Sphagesauria. Based on a partial tooth preserved and here described, we report the oldest record of a sphagesaurian taxa. This tooth has some ziphomorph features and exhibits multiple wear facets on the crown suggesting active oral food processing for the taxon. These crocodyliform groups play an important role in biogeographical studies, reinforcing similarities of the vertebrate palaeofauna of the Açu Formation with some North African and southern South American deposits. Despite being relatively rare, these crocodyliform remains display considerable diversity, and attest to the importance of the Potiguar Basin for understanding the Cretaceous faunas of western Gondwana.