ZoomDinosaurs.com DINOSAUR ANATOMY AND BEHAVIOR

SKELETAL FEATURES

Anatomically, dinosaurs have skeletal features that distinguish them from other archosaurs (crocodilians and pterosaurs). Dinosaurs have reduced fourth and fifth digits on their hands, their feet have three large toes, they have three or more vertebrae composing the sacrum (fused vertebrae by the hip), and have an open hip socket (a three-bone structure). This hip structure gives dinosaurs a posture that positions their legs under their bodies, unlike other reptiles, which have legs that sprawl out to the sides. For more information on T. rex's bones, click here.

HIPS
Dinosaurs are classified by their hip structure, into the Order Saurischia (meaning lizard-hipped) and the Order Ornithischia (meaning bird-hipped). This division by pelvic (hip) structure is based on their evolutionary tree; early in the Triassic period, dinosaurs branched into these two groups from their ancestor, thecodonts.

Saurischians	Ornithischians

SKULL
The dinosaurs were diapsids (as are all reptiles except turtles), animals that had two extra holes in the sides of their skulls.

Some Dinosaur Skeletons:

Brachiosaurus Skeleton Brachiosaurus was a tall, long-necked plant-eater.

Stegosaurus Skeleton See the bones of this huge, plated plant-eater.

Triceratops Skeleton A plant-eating dinosaur with three horns and a frill on its head.

Tyrannosaurus rex Skeleton The king of the dinosaurs; a huge meat-eater.

ZoomDinosaurs.com DINOSAUR ANATOMY AND BEHAVIOR

General Anatomy

Size

Teeth

Herds, Packs

Offense

Defense

Reproduction, Nests & Eggs

Blood Pressure

Skeleton

Tails

Brains

Male or Female?

Skin

Diet

Locomotion

Life Span

Hot or Cold Blooded?

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