Dilophosaurus is considered to be a ceratosaur, the earliest and most
'primitive' of the theropod groups. It was made famous in the movie "Jurassic
Park", but real Dilophosaurus was much larger, and there is no evidence, it
had neck frills or poison glands. This medium-sized theropod was the largest predator in its environment, a
powerful meat-eating animal, that ate smaller plant-eating dinosaurs. It was
probably a group animal, since three specimens were found together in
Arizona, USA. Dilophosaurus was quick and probably moved around in small
herds of family groups, covering a lot of territory. Dilophosaurus was a predator with a very unusual skull. It had a pair of
semicircular bony crests, that rose vertically on either side of the skull.
These crests were very thin in places and were given support by vertical
struts of bone. The tip of each crest narrowed into a spike at the back of
the skull. The significance of the crests is still unknown; they probably
served dual purposes: as mating displays and as heat radiators to cool the
blood and brain, allowing to pursue prey in hot environments. This effective desert predator was a speedy, slender and bipedual (walked
on two muscular legs), leaving bird-like footprints on land. Body about the
weight of a small horse with long, strong hind legs with four-toed feet,
short forelimbs with three-fingered hands that were flexible, with an
opposable thumb. Its hind legs, feet, were armed with very powerful claws,
that were probably used as weapons as well as for locomotion. Dilophosaurus
was probably a very rapid runner. It was carnivore, but it had loosely attached jaws which would have made
killing animals with its teeth difficult. It must have killed with its clawed
arms and legs.
- 208 - 194 MYA, Early Jurassic period.
- USA (Arizona).
Carnivore (meat eater)
- Juvenile 20ft (6m) long.
Scutellosaurus, the "little shield lizard", so named because of the
more than 300 little bony spikes (scutes) which gaurded its back, sides and
tail. This tough little creature (only about 13 ft. long) was sometimes compared to modern-day armored cars, so protective
was its outer body. Any meat-eating predator biting into this little shield
lizard would be in for a tough chew. Scutellosaurus was one of the earliest known ornithischians, whose jaw was
particularly well-adapted for cropping leafy plants. Back inside the cheeks
were teeth for cutting and chewing its favorite vegetation, which was
probably soft, fleshy and low-growing.
It was descended from small bipedal ancestors, and could walk only on its
hind legs, but because the heavy scutes of body armor made its body heavy at
the front, it undoubtedly walked on all four limbs most of the time.
Scutellosaurus possessed a small head compared to the size of its body, with a short skull
and a very long tail twice the length of its body and head. Its thin hind
legs were much longer than its arms, and the toes and fingers bore small,
- 208 - 200 MYA, Early Jurassic period.
- USA (Arizona).
- Various plants, seeds and fruits.
- Averaged 4ft (1.2m) long.