Nothronychus dinosaur family, artwork. This theropod dinosaur, found in what is now North America some 91 million years ago, lived during the Cretaceous. The type specimen is Nothronychus mckinleyi. The Nothronychus dinosaurs evolved from carnivorous ancestors, but were themselves herbivorous. They reached a height of around 3.5 metres, and had long curved claws. Several anatomical features of these theropods resembled those of birds, including a beak-like mouth, and feet with four toes, all facing forward.