The most antique and primitive dinosaur know in the world was found in Ischigualasto in the early 1990s.
Eoraptor lunensis, the "dawn raptor", is a small carnivore , about 1 meter length
and bears mix of primitive and specialized characters.
Though not known from as many specimens, nearly complete remains have been found.
The small size of the fossil, and its proportionately large eye-sockets
have led some paleontologists to suggest it was actually a much larger dinosaur,
and that the fossils discovered so far are from juveniles.