Paleontology News
Fossilized Vomit from a Spinosaurid Reveals a New Tropical Filter-Feeding Pterosaur
A fossilized spinosaurid regurgitation from Brazil reveals Bakiribu waridza, the first tropical filter-feeding pterosaur, shedding light on its diet, evolution, and predator-prey interactions.
Summary Points
Figure 3 from (Pegas R.V., et al, 2026) Reconstruction of the type specimens of Bakiribu waridza showing the filter feeding teeth. (CC-BY-ND-4.0)
Fossilized vomit revealed the first tropical filter-feeding pterosaur.
The species, Bakiribu waridza, means "comb mouth" in the Kariri language.
It had long jaws with dense, brush-like teeth for filtering small aquatic prey.
The fossil was preserved in the Romualdo Formation of Brazil's Araripe Basin.
Four fish were found alongside the pterosaur in the regurgitalite, showing predator-prey interactions.
The likely predator was a spinosaurid, though a giant pterosaur is also possible.
Bakiribu fills a gap in the evolutionary history of ctenochasmatid pterosaurs.
The discovery highlights the Araripe Basin as a window into Early Cretaceous tropical ecosystems.
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Spinosaurid Fossil Vomit Reveals New Tropical Pterosaur
This news article is based on the Journal Article (Pegas R.V., et al, 2026) from Scientific Reports (CC BY-NC-ND 4.0) and by a press release by the Centro de Memoria at FAPESPM.
Figure 2 from (Pegas R.V. et al, 2026), showing the concretion containing the remains of Bakiribu waridza gen. et sp. nov. and four associated fishes. (CC-BY-ND-4.0)
About 110 million years ago, two small pterosaurs, each about the size of a seagull, were flying over rivers or lakes in what is now the Araripe Basin in northeastern Brazil. They were likely hunting for food, or maybe just taking a bath, when a large predator swooped in and swallowed them. Later, this predator regurgitated the hard-to-digest parts, including the pterosaurs' skulls and a few fish it had eaten afterward. That vomit became fossilized, giving scientists a rare glimpse into an ancient food chain.
Meet Bakiribu waridza
Researchers studying this fossilized vomit in 2024 realized they had stumbled upon something extraordinary: the first tropical species of filter-feeding pterosaur, which they named Bakiribu waridza (comb mouth) in the Kariri language. This was a surprise, since decades of research in the Araripe Basin had already uncovered nearly 30 pterosaur species, none of which were filter feeders.
Built for Filter Feeding
Bakiribu waridza had incredibly long jaws lined with dense, brush-like teeth, perfect for filtering small aquatic creatures like crustaceans from rivers and lakes. The teeth were extremely close together, forming a comb-like arrangement that would have trapped tiny prey while allowing water to flow through. Paleohistological studies show that the teeth had well-preserved dentine and pulp cavities, hinting at both their strength and delicate structure.
Its feeding adaptations suggest that Bakiribu was a specialized forager in freshwater habitats, likely skimming along shallow waterways to filter food from the water. This makes it quite different from other pterosaurs found in the Araripe Basin, which were generally predators of fish or other small animals, rather than specialized filter feeders. Its anatomy indicates a lifestyle somewhat similar to modern flamingos or spoonbills, though in a completely different evolutionary context.
A Fossil with an Interesting Story
The fossilized vomit, called a "regurgitalite," shows the effects of stomach acid on the pterosaur bones. Interestingly, four fish were preserved alongside Bakiribu, likely eaten by the predator shortly after swallowing the pterosaur. All the bones are oriented in the same direction, suggesting the predator swallowed everything head-first, similar to how modern birds avoid choking on fish fins.
What Ate It?
Most researchers think the predator was a spinosaurid dinosaur, like Irritator challengeri, one of the few large fish-eating predators in the region that could handle both pterosaurs and fish. A giant pterosaur, Tropeognathus mesembrinus, is another possibility, though less likely-it was just big enough to swallow Bakiribu.
The Romualdo Formation and Its Environment
Bakiribu waridza was preserved in the Romualdo Formation, part of the Santana Group within the Araripe Basin. This formation is famous for its exceptional fossil preservation, particularly of fish, pterosaurs, and other vertebrates. During the Early Cretaceous, the region was a tropical coastal environment with rivers, lagoons, and shallow lakes. Such conditions, combined with fine sediment deposition, allowed delicate structures like teeth and bones to be preserved in remarkable detail. The formation offers a rare window into the ecosystems of tropical Gondwana during this period.
Where It Fits in the Family Tree
Bakiribu waridza belongs to the Ctenochasmatidae, a group of pterosaurs known for filter feeding. It sits evolutionarily between the Argentine Pterodaustro and the European Ctenochasma, bridging an important gap in this family's history. Before this discovery, ctenochasmatids had only been found in Europe, East Asia, and southern South America. This is the first one known from tropical Gondwana.
From Museum Shelf to Scientific Spotlight
The fossil was actually found in a museum collection at the Camara Cascudo Museum in Rio Grande do Norte during a survey of fish fossils. Recognizing its importance, part of the rock was donated to the Placido Cidade Nuvens Museum at URCA in Ceara to keep it in its region of origin. This move followed ethical, decolonial practices, similar to previous work with the dinosaur Ubirajara jubatus.
Conclusion: Rare Glimpse of Ancient Life
Thanks to its exceptional preservation, this fossil gives direct evidence of predator-prey interactions in the Early Cretaceous. Bakiribu waridza shows that filter-feeding pterosaurs weren't just living in temperate regions-they thrived in tropical freshwater habitats too, highlighting the diversity and complexity of the Araripe Basin ecosystem.
This discovery fills a gap in our understanding of pterosaur evolution and biogeography. Bakiribu waridza is the first tropical ctenochasmatid and the first archaeopterodactyloid documented from the Romualdo Formation. It's a reminder that even decades-old museum specimens can hold exciting surprises-and that the Araripe Basin continues to be a window into Early Cretaceous life.
Illustration of two filter-feeding pterosaur Barikibu waridza in the Early Cretaceous Romualdo Formation. The spinosaurid in the background that may have eaten them. Image Credit: Julio Lacerda (Pegas R.V. et al, 2026) (CC-BY-ND-4.0)
Journal Articles:
Pegas, R.V., Aureliano, T., Holgado, B. et al. A regurgitalite reveals a new filter-feeding pterosaur from the Santana Group. Sci Rep 15, 37336 (2025). https://doi.org/10.1038/s41598-025-22983-3
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