is one of the earliest known dinosaurs. It was one one of the
very first to ever walk on Earth.
Although it was small, it was a fierce
predator. Its speed and intelligence destined it to become the
ancestor of many evolved species and the
dinosaurs becoming the dominant land creatures. Eoraptor had the characteristics
of later dinosaurs - serrated teeth, grasping hands (although there is
some speculation that it occasionally walked using all four limbs),
light hollow bones and a strong, light skull. Although it lived at the
same time as the larger Herrerasaurus (which may have eaten
Eoraptor), it has some significant differences. Some of its teeth
were shaped differently and the bones in its hands were more
primitive. Later dinosaurs tended to lose fingers, and by the time T.
rex came onto the scene, it had only two fingers. Eoraptor had
five. Even Herrerasaurus, which had five fingers, had a less
useful fifth finger.
A Eoraptor skull was
discovered in a single rock by Ricardo
Martinez in 1991 in Argentina, South America, in the Ischigualasto
Basin. This area was a river valley during the late Triassic period
but is a dry, eroding desert badlands today. Eoraptor was found in the
same rock formation that yielded Herrerasaurus, another very early theropod.
The Argentina Natural History Museum sent a team to investigate:
Paul Sereno, Fernando Novas and others. They sound found an almost
complete skeleton and have since discovered two others. This
creature has greatly increased scientists' knowledge of how dinosaurs
developed and evolved. There are so few dinosaurs known from this time
period that finding a complete skeleton of such an early member of the
dinosaur family is a big help in expanding our knowledge of the early
Eoraptor was named by paleontologists P. Sereno, Forster,
Rogers, and Monetta in 1993.