Herrerasaurus (Huh-RARE-oh-SORE-us) Meat eater, 13 feet long, Late Triassic Period. 210 million years ago located in South America. Herrerasaurus was the first large meat-eating dinosaur to evolve. Though it was the biggest dinosaur in its time, the biggest animals were relatives of crocodiles. The rocky desert where Herrerasaurus was found is so dry and rocky that it’s called “The Valley of the Moon.”