Parasaurolophus is a genus of ornithopod dinosaur from the Upper Cretaceous of what is now North America, about 76.5–73 million years ago. Its name means "near crested lizard". It was given this name because when it was first discovered scientists thought it was related to Saurolophus. It was a herbivore that walked both as biped and a quadruped. It probably lived in herds.