Digestive contents and food webs record the advent of dinosaur supremacy.

The early radiation of dinosaurs remains a complex and poorly understood evolutionary event. Here we use hundreds of fossils with direct evidence of feeding to compare trophic dynamics across five vertebrate assemblages that record this event in the Triassic-Jurassic succession of the Polish Basin (central Europe). Bromalites, fossil digestive products, increase in size and diversity across the interval, indicating the emergence of larger dinosaur faunas with new feeding patterns.