A regurgitalite reveals a new filter-feeding pterosaur from the Santana Group

The Santana Group in Northeast Brazil has yielded a remarkable discovery: the first filter-feeding pterosaur from the tropics, named Bakiribu waridza gen. et sp. nov. This new taxon provides key insights into the evolutionary history and ecological diversity of Ctenochasmatidae, a clade known for its specialized feeding adaptations. Bakiribu exhibits extremely elongated jaws and dense, brush-like tooth rows, similar to Pterodaustro but distinct in tooth cross-section and spacing. Paleohistological analysis of the teeth revealed well-preserved dentine and pulp cavities. Phylogenetic analysis recovers Bakiribu as the sister taxon to Pterodaustro, forming a clade more closely related to Ctenochasma than to Gegepterus, which is reinterpreted as a non-ctenochasmatine. Regarding some specific traits such as tooth density, elongation, and count, Bakiribu is intermediate between Ctenochasma and Pterodaustro, thus partially bridging a key evolutionary gap within Ctenochasmatinae. Taphonomic features support the interpretation of the fossil assemblage as a regurgitalite. This discovery brings crucial data for understanding biogeographic dispersal and ecological specialization within Ctenochasmatinae during the Early Cretaceous, and offers rare evidence of predator-prey interactions in the Romualdo Formation paleoecosystem. Together, these findings further underscore the importance of the Araripe Basin as a window into the Early Cretaceous biodiversity.