The Herrerasaurus name means Herrera's lizard. A Goat Herder named Victorino Herrera first saw the fossils for the Herrerasaurus in 1959. It was described and named by Osvaldo Reig, a paleotologist. There has been many discoveries of this dinosaur in the northwest Patagonia, Argentina Region.

In 1988 a pretty much complete skull fossil was discovered clearing the debate on which classification it should be in. Today Herrerasaurus belongs in the a theropod or a saurischian. Before that a basal theropod or basal sauropodomorph. Its even been accused of not being a dinosaur at all.

The Herrerasaurus was a 3 to 6 foot carnivore with a long tail and a smaller head. This dinosaur was not very unique towards other dinosaurs in its Mid-Triassic period such as Euparkeria. It had five pairs of skull openings(fenestrae) in its skull and two of which were for ocular and nasal openings. There was also two antorbital fenestrae and a pair of tiny, 1-centimeter-long (0.4 in) slit-like holes called promaxillary fenestrae between the eyes and the nostrils. Behind the eyes were large infratemporal fenestrae as well. These holes helped for weight reduction of the skull.