ORNITHISCHIAN
DINOSAURS
The Ornithischian dinosaurs had a hip
structure similar to that of birds, but they were not the ancestors of
birds. They outnumbered the Saurischians. The Ornithischians were vegetarian,
and included two-legged, plated, armored, and horned dinosaurs. Major divisions
of the Ornithischian dinosaurs:
Pachycephalosaur
Ornithopods
*Two-legged walk *No body armor *Spiked
hand *Lived in the early Jurassic to Cretaceous
Thyreophorans ("shield bearers")
*Armored plates on the body *Lived
in the early Jurassic to Cretaceous
Ceratopsians, horned dinosaurs
*Beaked *Lived during the Cretaceous
Pachycephalosaurs, dome-headed
dinosaurs
*Huge bony skulls *Lived during
the Cretaceous
Theropods
*Led to the birds! *Fast and agile
*Carnivorous diet *Sharp, slicing teeth and well-developed jaw muscles
*Clawed hands with three main digits
*Bipedal walk *Strong legs with bird-like, three-toed, clawed feet
*Large eyes, indicating good eyesight.
*pencil-shaped teeth *Usually walked on four legs *Largest land animals
ever!
SAURISCHIAN
DINOSAURS
The Saurischian dinosaurs (Order Saurischia)
were the ancestors of
birds. They had a hip structure similar
to that of lizards.
The Saurischians are divided into the
Sauropods, four-legged herbivores,
and the
Theropods, two-legged carnivores.
The oldest known dinosaurs, from the
middle Triassic period, are Saurischians.
Major divisions of the Saurischian
dinosaurs:
Sauropods
*Plant eaters *Small heads with spatulate
or pencil-shaped teeth *Usually walked on four legs
*Largest land animals ever!