A Review of Vertebrate Beak Morphologies in the Triassic; A Framework to Characterize an Enigmatic Beak from the Ischigualasto Formation, San Juan, Argentina

A unique fossil beak (PVSJ 427) from the Late Triassic Ischigualasto Formation, Argentina, provides insight into early beak evolution and ecological convergence. The iron-rich cast fossil, triangular with a concave midline shelf, lacks clear synapomorphies but resembles ornithischian dinosaur predentaries, suggesting an early evolutionary origin of this structure. Researchers analyzed phylogenetic distribution and morphology of Triassic beaks to create a framework for estimating beak similarity, placing PVSJ 427 alongside other vertebrate clades from the period. This study advances understanding of edentulous dietary modifications in early reptiles and their ecological implications, indicating that the animal bearing PVSJ 427 was ecologically convergent with the earliest ornithischian dinosaurs.

Wynd, B. M., Martínez, R. N., Colombi, C., & Alcober, O. (2020). A Review of Vertebrate Beak Morphologies in the Triassic; A Framework to Characterize an Enigmatic Beak from the Ischigualasto Formation, San Juan, Argentina. Ameghiniana, 57(4). https://doi.org/10.5710/amgh.13.05.2020.3313