Order

Dinosaurs are divided into two groups based on hip structure.

	The Saurischia had a hip-bone structure similar to lizards.
	The Ornithischia had a hip-bone structure similar to birds.

Select an order of dinosaurs:
  Saurischia (lizard-hipped) Ornithischia (bird-hipped) unknown

Sub-order

Saurischian dinosaurs are divided into two sub-orders:
	The Theropoda were meat eaters which walked on two legs. They had clawed hands and strong jaws. Theropods were the ancestors of the birds.
	The Sauropodomorpha were plant eating dinosaurs which walked on four legs. They included the Sauropoda and the Prosuaropoda. The Sauropoda were huge dinosaurs with small heads and long necks and tails. The Prosauropoda were the ancestors of the Sauropods. They were much smaller than the Sauropods..
Ornithischian dinosaurs are divided into the following sub-orders:
	The Thyreophora were plant eating, armored dinosaurs which walked on four legs. They included the Ankylosauria and the Stegosauria. The Ankylosauria were armored, plant eating dinosaurs which walked on four legs. The Stegosauria were plant eating dinosaurs with armor plates and spikes.
	The Marginocephalia were plant eating dinosaurs with horns or thick skulls. They included the Ceratopsia and the Pachycephalosaurs: .The Ceratopsia were plant eating dinosaurs with horns and beaks. The Pachycephalosaurs were plant eating, dome-headed dinosaurs with huge bony skulls.
	The Ornithopods were plant eating dinosaurs with no body armor. They included the Iguanadontia. The Iguanadontia were plant eating, beaked dinosaurs with hoof-like claws and a spike on each thumb.

Select a sub-order of dinosaurs:
Ankylosauria Ceratopsia Iguanadontia Marginocephalia Ornithopoda Pachycephalosauria Prosauropoda Sauropoda Stegosauria Theropoda Thyreophora unknown