Histology and fossil diagenesis of a pterosaur tooth from the Crato Formation (Lower Cretaceous of Brazil).

Pterosaur dental biology remains poorly understood despite its importance for comprehending feeding strategies and flight adaptations. Here, we present the first comprehensive histological analysis of an ornithocheiriform pterosaur tooth from the Lower Cretaceous Crato Formation (Santana Group, Northeast Brazil). Specimen LPP-UFRN 3002 exhibits thin prismless enamel (61 μm thickness), orthodentine with dense tubule networks, and 82 von Ebner lines indicating rapid tooth formation. Quantitative comparison across major clades of extinct reptiles reveals that pterosaurs demonstrate the most accelerated tooth development among archosauriforms, with formation times of 54-82 lines compared to 185-933 lines in non-avialan dinosaurs, 50-283 lines in crocodyliforms, and 342-426 lines in mosasaurs. The rapid tooth development and thin enamel documented in ornithocheiriform pterosaurs could enable the maintenance of lightweight skulls, essential for powered flight, while ensuring continuous replacement for effective prey capture. The specimen preserves microstructural detail despite diagenetic calcite permineralization and partial focalized substitution, a characteristic of the Crato Formation carbonate environment. These findings demonstrate that ornithocheiriform pterosaurs evolved a unique dental strategy, prioritizing replacement efficiency over individual tooth durability, which contrasts with the extended formation times characteristic of large-bodied mosasaurs and herbivorous dinosaurs. This research establishes dental histology as critical for understanding pterosaur paleobiology and provides quantitative data for reconstructing ecosystem dynamics throughout the Mesozoic.