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bioRxiv · 10.64898/2025.12.10.693067

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

Unwin, D. M.·Smith, R. E.·Cooper, S. L. A.·Martill, D. M.
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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.

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Unwin, D. M., Smith, R. E., Cooper, S. L. A., Martill, D. M.. 2025-12-12. Reinterpretation of Bakiribu waridza from the Romualdo Formation (Lower Cretaceous) of Brazil: a fish not a pterosaur. https://doi.org/10.64898/2025.12.10.693067

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