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Dinosaurs - Triassic Gallery
In the Triassic period, only the
lizard-hipped dinosaurs lived in the
Ancient Southwest. There were two legged meat eaters called Theropods,
and there were four legged plant eaters called Sauropods.
Coelurosaurs
In New Mexico, the oldest type of dinosaur in North America has been found,
and they were found in family groups. These early dinosaurs are called
Coelurosaurs and were small Theropods that stood on two slender hind legs,
had long necks, small heads, short front arms, and long tails. Their name
means they were hollow-boned dinosaurs, which made them light and probably
fast runners.
The Coelurosaurs are one of the few Dinosaurs with relatives living in
all three periods of the Mesozoic Era. These hollow-boned creatures are
the ancestors of today's birds, and make a link that proves dinosaurs
are not really extinct - they evolved into birds!
An example of a Coelurosaurs is a Coelophysis, Paleontologist and Ichnologists
think they lived in herds, cared for their young, and ate meat and insects.
Prosauropods
Another very different types of dinosaur lived in the southwest during
the last half of the Triassic. These were Prosauropods, meaning ancestors
of the Sauropods. Sauropods are the huge four legged plant eaters - like
Brontosaurs - many of us easily recognize as a major dinosaur type. The
Prosauropods were smaller than their descendents and had the ability to
run on their hind legs or stand on four legs to eat or drink.
The Anchisaurus was a Prosauropod measuring eight feet in length, his
long neck and long heavy tail together were twice as long as his body.
He could stand and walk on all fours, but probably raised up on his stronger
hind legs to run, using his four toes for balance. The Anchisaurus was
a plant eater with a long flexible neck helpful in gathering leaves from
tall tress, and to drink with out getting down on its belly.
Segisaurus
A small rabbit-sized dinosaur that lived in the Ancient southwest was
the Segisaurus, named after the canyon where it was found in Arizona.
This small creature was apparently a fast runner, ate small reptiles,
and it bones were solid, not hollow. The Segisaurus lived during the late
Triassic and Early Jurassic.
Dilophosaurus
The Dilophosaurus was a crest headed dinosaur that ran on two strong heavy
back legs weighed about 1,000 pounds, and measured 20' nose to tail. He
lived in Arizona during the late Triassic and early Jurassic when it was
a desert. He had sharp dagger-like teeth for eating prey and the claws
on his front and hind hands and feet helped him catch his meals. His unusual
head crest was made o two side be side crests on the top of his head.
When found in Arizona, there was a group of three discovered together,
implying it may have run in a small herd.
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