Bayesian Analysis Resolves Dinosaur Turnovers During the Jurassic– Cretaceous Transition Driven by Climate Shifts and Biotic Interactions

Dinosaur ecosystems are thought to have undergone a major reorganization across the Jurassic–Cretaceous (J–K) transition, but whether this reflects a true extinction event or geographic and sampling biases remains debated. Here we test the hypotheses by analyzing occurrence data of Middle Jurassic to Early Cretaceous dinosaur taxa using the Bayesian PyRate and grid cell rarefaction framework, which mitigate temporal and spatial sampling biases, and the recently developed Bayesian deep neural network model. Our results show a selective extinction across the J–K boundary, with Sauropoda suffering disproportionately higher extinction rates than Ornithischia and Theropoda. Moreover, smaller-bodied dinosaur species show elevated origination and extinction rates through the J–K extinction, which correlates strongly with sea-level fluctuations, paleotemperature, atmospheric CO₂ changes, and tectonic activity. With diversification of angiosperms, both origination and extinction rates of dinosaurs show noticeable fluctuations around 130 Ma, suggesting that the early spread of flowering plants may have influenced dinosaur evolution.