Reinterpretation of Bakiribu waridza from the Romualdo Formation (Lower Cretaceous) of Brazil: a fish not a pterosaur

Abstract

Fragmentary remains of fossil vertebrates from the Romualdo Formation (Lower Cretaceous) of Brazil, preserved in association with two fish were interpreted as two individuals of a new genus and species of ctenochasmatine pterosaur, Bakiribu waridza Pegas et al., 2025. Comparison with a range of fossils from the same geological unit show that the remains represent the gill arch apparatus of a large actinopterygian fish. This reinterpretation, which mirrors a comparable event in the mid twentieth century when the remains of a supposed ctenochasmatine pterosaur, Belonochasma aenigmaticum, were reidentified as part of the gill apparatus of a fish, does not affect our current understanding of the evolutionary history of pterosaurs.