Long before horses thundered across the plains, a plant-eating giant with hooves of its own left footprints in the mud. Newly described fossils of Edmontosaurus annectens—a duck-billed dinosaur that ...

A site in the San Juan Basin of northwestern New Mexico is providing a rare glimpse into the last days of the dinosaurs. Rocks and fossils at the Naashoibito Member site show an ecosystem that was ...