20 July 2007
Vol 317, Issue 5836

About The Cover

Cover image expansion

COVER Depiction of four dinosaurs and dinosaur precursors from fossils found at the Hayden Quarry of northern New Mexico. The dinosaur precursors Dromomeron romeri (lower left) and a Silesaurus-like animal (bottom center) coexisted during the Late Triassic with the dinosaurs Chindesaurus bryansmalli (top center, with crocodylomorph in its mouth) and a coelophysoid theropod (upper right), indicating that the initial rise of dinosaurs was prolonged rather than sudden. See page 358. Image: Donna Braginetz