Herrerasaurus's long, agile legs gave this bipedal predator an advantage over slower moving four-legged reptiles also living in early Late Triassic South America.
Herrerasaurus was not the earliest prosauropod, but it was the biggest of its family. Its big head had two rows of teeth shaped like sickles. With long back legs and large front legs, it was probably able to move quickly across rough ground. Its front legs probably helped it climb across rocky land.
From bones dug up in Argentina, Herrerasaurus is known to have been about 10 feet long and to have weighed around 220 pounds. Others in the family have been found in China. Not many are believed to have existed. They did not seem to survive beyond the early Jurassic period, about 200 million years ago.
Two young Herrerasaurus (left) here vie with a big rauisuchid, Saurosuchus, for the remains of a dead rhynchosaur, watched by the small, primitive theropod Eoraptor (centre) and by mammal-like reptiles (right).
Diet: Reptiles
Size: Length 3m
Weight 100kg
Classification:
Family Herrerasauridae
Suborder Theropoda
Order Saurischia
Time (million years ago): 228
