Herrerasaurus: Triassic Theropod Predator

Herrerasaurus ischigualastensis, discovered in Argentina's Ischigualasto Formation, was among the earliest large predatory dinosaurs. Reaching 6 meters in length and 350 kilograms, this Late Triassic carnivore lived approximately 231 million years ago when dinosaurs remained a minor component of terrestrial fauna. Its anatomy clarifies the sequence of changes during early dinosaur evolution and demonstrates that large body size in theropods emerged within the lineage's twenty million years.