Page 19 - Reptiles & Dinosaurs (Britannica Illustrated Science Library)

14 DINOSAURS REPTILES AND DINOSAURS 15

The First Giant Herbivore Head

Its brain was small in
proportion to the weight
his primitive saurischian was among the first to usher in the age of the dinosaurs in the late of its body, so it is not
believed to have been
Triassic Period, about 210 million years ago. Dinosaurs had already been in existence for very intelligent.
T some time, but they were smaller predators thus far. The saurischian was clearly one
of the first that fed exclusively on plants and that reached the immense sizes typical of
herbivores. Many fossils have been found in over 50 separate locations. The secret PLATEOSAURUS
of this dinosaur's survival is believed to have been the lack of competition for Plateosaurus engelhardti
food, since no other herbivore of the time grew as large. Its name, Size 26-33 feet (8-10 m)
which means “lizard-hipped,” was given to it in 1837 by the In the Diet Herbivorous
German naturalist Hermann von Meyer. Treetops Habitat Semiarid Regions
Its long neck helped it to Epoch Late Triassic
reach the tops of trees.
Its mouth had pouches Range Europe
for storing food while it
chewed.
WHERE IT LIVED
Its fossils were found in
semiarid areas of what
are now Germany,
Plateosaurus France, and Switzerland.
At the time, those areas
engelhardti were part of the
supercontinent Pangea.
These prosauropods, of the suborder
Sauropodomorpha, were among the primitive
herbivorous dinosaurs that were forerunners of the
giant sauropods of the Jurassic Period. However, they
were not actually ancestors of these animals. It is
known that they associated with others of their
own species because, in many areas, several SEXUAL DIMORPHISM
specimens have been found together. Because of It is thought that
the hot, dry conditions that prevailed where they Plateosaurus varied in
lived, it seems that they migrated constantly in size according to its MATING
search of food, which consisted of conifers and environment. There is Plateosaurs were polyandrous, meaning that the
palm trees. also evidence that dominant matriarch had from three to five male
males and females had mates, who competed for her attention during
different shapes. mating season. The eggs, of various sizes, were
cared for by each respective male.

Movement
It moved about on its
four muscular legs, but
it could probably stand
up on its hind legs and
run quickly.

EVENTUAL
BIPEDS
Its powerful hips
supported the entire
weight of its body when
it stood up on its hind
legs to reach food in the Defensive Claw
high branches of trees. Upper Limb Hind
This animal had few defensive Foot
Claw resources. However, one of the toes of
WEIGHT- its front feet had a powerful claw that
BEARING it used to cut branches and for self-
TOES defense. In reality, however, its best
defense was to run.