Page 63 - The Dinosaur Book and Other Wonders of the Prehistoric World (DK-Smithsonian)

This close relative of the
first dinosaurs had a very
slim, lightweight body.

Marasuchus
Silesaurus

Relatively short arms show
that this animal ran on its
back legs, like early dinosaurs.

Eoraptor’s
fossils are
some of the
The long front limbs oldest known
were used for walking,
but Silesaurus was dinosaur
probably able to rear
up on its hind legs. remains.

Thecodontosaurus was
about 6 ⁄2 ft (2 m) long and
1
had a bulky body.
Thecodontosaurus
AGILE ARCHOSAURS
Early dinosaurs and their close relatives were all
archosaurs, sharing features that make them hard to
tell apart. They all had long legs held beneath the body,
an agile build, and gaps in their skulls filled with air.
Gap in front of the Dinosaurs
eye socket was an had hip joints
archosaur feature. similar to ours.

The hands were used
One of the lower leg to gather food.
bones of a dinosaur
was very thin.

as well as small animals. These light, agile a variety of foods. They soon gave rise to
creatures were closely related to animals like specialized predators like Herrerasaurus, as
Nyasasaurus, which may have been one of the well as plant-eaters like Thecodontosaurus.
first true dinosaurs. The first definite dinosaurs— These animals were the ancestors of the giant
animals like Eoraptor—lived about 230 million dinosaurs that were to dominate life on land for
years ago and were probably omnivores that ate the next 140 million years. 61

US_060-061_The_first_dinosaurs.indd 61 26/04/18 3:30 PM