Stock Photo - 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.