The most primitive
Herrerasaurus was among the first dinosaurs that inhabited the Earth. All known fossils of this carnivore have been found in north-western Argentina and dated to 231.4 million years ago. Among the most active predators of the Triassic, he was in competition only with the great terrestrial crocodiloids of that time.
It was a lightly built bipedal carnivore with a long, upright tail and a relatively small head. It preyed upon large-sized herbivore and small-sized carnivore dinosaurs, probably by attacking them with its legs and smashing the victim with its powerful claws.
Herrerasaurus had very primitive features; the presence of cervical vertebrae, the sacrum formed by three vertebrae and a hand with three fingers, the third being the longest one. Although it was a primitive form of a Saurischian dinosaur, it was only 4.5 meters long. Its skull was about 1 foot long with a very well-developed muzzle that represented more than the half of the head.
