Herrerasaurus was one of the first dinosaurs to roam the Earth.
A contemporary of Eoraptor on the late Triassic riverbanks of Argentina, Herrerasaurus was a much bigger and more advanced theropod. Because of the difference in size, it must have hunted different prey from its smaller relative. Its skeleton was found in 1959, although it was several decades before it was scientifically studied. The complete skull was not found until 1988.
This dinosaur held its tail high off the ground when it walked. It stood upright, moving about on its long, strong back legs and probably ran very fast to catch its prey.
Name: Herrerasaurus, meaning ‘Herrera lizard’, after Victorio Herrera, its discoverer
Size: about 3-5m long and 1m high
Food: mammals, lizards and other dinosaurs
Lived: about 230-215 million years ago in the Late Triassic in the north of Argentina
Herrerasaurus represents the roots of dinosaur evolution. It cannot be classified as either a Saurischia or Ornithischia. This early and very primitive dinosaur had four toes on its back feet. This separates it from other carnivorous dinosaurs, which had three toes.
A big animal with heavy jaws and 5cm-long serrated teeth, Herrerasaurus nevertheless had the appearance and probable lifestyle of the big theropods to come. It has the hinged lower jaw of other theropods. The foot bones are quite primitive, retaining the first and fifth toes that later theropods were to lose. Herrerasaurus has complex ear bones, suggesting that it had a keen sense of hearing which would help in hunting.
Herrerasaurus lived around 230 million years ago, when dinosaurs first appeared in the Triassic Period but were not yet dominant. These earliest dinosaurs were all small predators, like Coelophysis in North America. They competed with more powerful non-dinosaur carnivores for food, including the rauisuchids, some of which were like huge crocodiles. Larger predators ate Herrerasaurus and other small dinosaurs.
Herrerasaurus killed and ate mammals, lizards and perhaps other small carnivorous dinosaurs. It attacked with its front and back feet, and tore its victim with its long claws. Herrerasaurus held its prey in its short, strong front legs.
Several skeletons of this dinosaur have been discovered in northwest Argentina in recent years. Herrerasaurus lived at a time when South America was still joined to the other continents. Members of its dinosaur family have been found as far away as China.