Sauropodomorph dinosaurs underwent drastic changes in their anatomy and ecology throughout their evolution. The Late Triassic Thecodontosaurus antiquus occupies a basal position within Sauropodomorpha, being a key taxon for documenting how those morpho-functional transitions occurred. Here, we redescribe the braincase osteology and reconstruct the neuroanatomy of Thecodontosaurus, based on computed tomography data. The braincase of Thecodontosaurus shares the presence of medial basioccipital components of the basal tubera and a U-shaped basioccipital-parabasisphenoid suture with other basal saurop-odomorphs and shows a distinct combination of characters: straight outline of the braincase floor, an undivided metotic foramen, an unossified gap, large floccular fossae, basipterygoid processes perpendicular to the cultriform process in lateral view and a rhomboid foramen magnum. We reinterpret these braincase features in the light of new discoveries in dinosaur anatomy. Our endocranial reconstruction reveals important aspects of the palaeobiology of Thecodontosaurus, supporting a bipedal stance and cursorial habits, with adaptations to re-tain a steady head and gaze while moving. We also estimate its hearing frequency and range based on endosseous labyrinth morphology. Our study provides new information on the pat-tern of braincase and endocranial evolution in Sauropodomorpha.
- Late Triassic
- sensory organs