A newly identified pterosaur species, Bakiribu waridza, represents the first confirmed filter-feeder from tropical regions. The discovery, made in Brazil’s Araripe Basin, sheds new light on the evolution and paleobiogeography of these ancient flying reptiles.
A Unique Filter-Feeder from Gondwana
Bakiribu waridza lived approximately 113 million years ago during the Early Cretaceous period, within the supercontinent Gondwana. Belonging to the Pterodaustrini group within the Ctenochasmatidae clade, this pterosaur exhibits specialized adaptations for filter-feeding.
Recent discoveries have revealed a greater diversity among Ctenochasmatidae than previously understood. These pterosaurs thrived during the Late Jurassic and Early Cretaceous, displaying diverse morphologies and broad geographical distribution. Discoveries from China, South America, and Europe have enhanced understanding of their ecology and evolutionary history.
Specialized Adaptations for Filter-Feeding
Bakiribu waridza possessed extremely elongated jaws and dense, brush-like tooth rows, similar to the Pterodaustro species, but with distinct tooth cross-section and spacing. Within Ctenochasmatidae, the Ctenochasmatinae subclade is distinguished by elongated snouts and numerous fine teeth, adaptations linked to their unique feeding strategies.
The evolutionary trajectory of this group is exemplified by Liaodactylus primus, which transitioned from fish-catching to filter-feeding. Pterodaustro guinazui exhibits an extreme morphology with thousands of hyper-elongated, baleen-like teeth on its lower jaw, indicating a hyper-specialization toward filter-feeding.
Fossil Discovery and Regurgitalite Evidence
The fossilized remains of two Bakiribu waridza individuals were found within a calcareous concretion from Brazil’s Romualdo Formation. The concretion also contained four fossil fish, likely the Early Cretaceous bony fish Tharrhias.
The co-occurrence of densely packed, semi-articulated, and fragmented pterosaur bones, aligned with a cluster of similarly aligned fish, suggests the assemblage is a regurgitalite—a mass of indigestible material expelled orally by a predator. This provides rare direct evidence of trophic interactions in the Early Cretaceous Araripe paleoecosystem.
Paleobiogeographic Significance
Bakiribu waridza exhibits a mosaic of traits shared with both South American and European relatives. Its unique combination of anatomical traits—particularly its elongated jaws, dense dentition, and tooth implantation—sheds new light on the evolutionary trajectory of filter-feeding pterosaurs.
The discovery fills a paleobiogeographic gap in the distribution of Ctenochasmatinae and underscores the significance of understudied museum specimens for revealing key evolutionary and paleoecological insights. The Araripe Basin serves as a critical window into Early Cretaceous biodiversity, ecological complexity, and continental-scale faunal exchanges.
This discovery confirms that filter-feeding pterosaurs were not limited to specific regions, but thrived in diverse ecosystems, including tropical environments. Further research will be crucial to understand the full extent of their distribution and evolutionary relationships
