Dinosaur Shapes and Sizes

Origins of the Dinosaurs

TUOJIANGOSAURUS

Dorling Kindersley

Parasaurolophus Skull

Dorling Kindersley

STYRACOSAURUS
"Spiked lizard"
Styracosaurus Printout

Styracosaurus was about 18 feet (5 m) long, 6 feet (1.8 m) tall, and weighed up to 3 tons.

WHEN STYRACOSAURUS LIVED
Styracosaurus lived in the late Cretaceous period, about 77-70 million years ago. It was among the last of the dinosaur species to evolve before the Cretaceous-Tertiary extinction 65 million years ago. Among the contemporaries of Styracosaurus were Tyrannosaurus rex, Ankylosaurus (an armored herbivore), Corythosaurus (a crested dinosaur), and Dryptosaurus (a meat-eating dinosaur).

BEHAVIOR
Styracosaurus may have been a herding animal, like some other ceratopsians. This hypothesis is supported by the finding of bone beds, large deposits of bones of the same species in an area. Styracosaurus hatched from eggs, and the young may have been cared for by parents.

When threatened by predators, Styracosaurus may have charged into its enemy like a modern-day rhinoceros does. This would have been a very effective defense.

INTELLIGENCE
Styracosaurus was a ceratopsian, whose intelligence (as measured by its relative brain to body weight, or EQ) was intermediate among the dinosaurs.

Click here for information on the styracosaurus

PARASAUROLOPHUS
"Beside Saurolophus (Crested Lizard)"

Activities and Printouts

• Brief Parasaurolophus Fact Sheet

• Parasaurolophus printout

• K-3 level Parasaurolophus printout

• Interactive Parasaurolophus quiz

Click here to find additional information on the parasaurolophus

STEGOSAURUS
"Covered Lizard" or "Roof Lizard"

Activities and Printouts

• Stegosaurus fact sheet

• A Stegosaurus page to print out

• Print out a K-3 level Stegosaurus info page to color!

• Paint a Stegosaurus online - an interactive coloring book.

• Print out a labeled Stegosaurus skeleton

• Stegosaurus Find It! Quiz print out

• On-line picture quiz on Stegosaurus

• Plant eater
• Very small head with a tiny brain and toothless beak
• Large, flat, bony, triangular plates along its back
• A heavy, spiked tail for protection
• Walked on four legs, but the back legs were twice as long as its front legs

Click here for information on the stegosaurus

Apatosaurus/Brontosaurus Fact Sheet
Go to a Printable Version

Dinosaur/Paleontology Dictionary

Click here for information on the Apatosaurus

Pteranodon Fact Sheet
Go to a Printable Version

Dinosaur/Paleontology Dictionary

Protoceratops
"First Horned Face"

Protoceratops printout
K-3 Protoceratops printout

Protoceratops was about 6 to 8.2 feet (1.5-2.5 m) and weighed roughly 900 pounds (400 kg). It was about 3 feet tall ( to the top of the shoulders).

WHEN PROTOCERATOPS LIVED
Protoceratops lived in the late Cretaceous period, about 86 to 71 million years ago, toward the end of the Mesozoic, the Age of Reptiles.

BEHAVIOR
Protoceratops was probably a herding animal, like some other ceratopsians. This hypothesis is supported by the finding of bone beds, large deposits of bones of the same species in an area, and large groups of nests. Each nest had 12 or more eggs, laid in a spiral fashion.

Sexual dimorphism (the physical differences between the sexes) in frill size has also been noted, with males may have had larger frills than females, indicating that the frill may have been used in courtship and mating (P. Dodson, 1976, Journal of Paleontology).

INTELLIGENCE
Protoceratops was a ceratopsian, whose intelligence (as measured by its relative brain to body weight, or EQ) was intermediate among the dinosaurs.

DIET
Protoceratops was an herbivore, a plant eater. It probably ate cycads and other prehistoric plants with its tough, hook-like beak.

LOCOMOTION
Protoceratops walked on four short legs; it was a relatively slow dinosaur. Dinosaur speeds are estimated using their morphology (characteristics like leg length and estimated body mass) and fossilized trackways.

DISCOVERY OF FOSSILS
Protoceratops was first discovered in the Gobi Desert in Mongolia in the 1920's. It was named by Walter Granger and W. K. Gregory.

Numerous fossils have been found, from eggs in nests to juvenile to mature specimens. Sexual dimorphism (the physical differences between the sexes) in frill size has also been noted, with the adult male possibly having a more pronounced frill than the adult female.

A fossil of Protoceratops has been found with one of a Velociraptor; the Velociraptor had been attacking the Proroceratops, which had butted in the chest of the Velociraptor.

CLASSIFICATION
Protoceratops was an ornithischian dinosaur, the order of bird-hipped, herbivorous dinosaurs. It was a Ceratopsian ( a suborder of frilled, herding herbivores, that include Triceratops, Styracosaurus, etc.), and a Protoceratopsid (an early ceratopsian, which included Montanoceratops, Leptoceratops, and others).

PROTOCERATOPS LINKS
Protoceratops printout

K-3 Protoceratops printout to color

American Museum of Natural History: Protoceratops

TUOJIANGOSAURUS

(pronounced Too-oh-gee-ANG-oh-SAWR-us) A stegosaurid, a quadrupedal, plant-eating dinosaur about 23 feet (7 m) long with double rows of plates along its back, a toothless beak, a long, low-hanging head, spoon-shaped teeth, 2 shoulder spikes, and a 4-spiked tail. It was from the late Jurassic period, about 163-150 million years ago in China. It was named in 1977 by Shiwu Zhou, Dong, Zhang, and Li.

Tyrannosaurus rex
the "Tyrant lizard king"

T. rex was a huge meat-eating dinosaur that lived during the late Cretaceous period, about 85 million to 65 million years ago. T. rex lived in a humid, semi-tropical environment, in open forests with nearby rivers and in coastal forested swamps. The seasons were mild.

Until recently, Tyrannosaurus rex was the biggest known carnivorous dinosaur; Giganotosaurus and Carcharodontosaurus are slightly bigger.

ANATOMY
Tyrannosaurus rex was a fierce predator that walked on two powerful legs. This meat-eater had a huge head with large, pointed, replaceable teeth and well-developed jaw muscles. It had tiny arms, each with two fingers. Each bird-like foot had three large toes, all equipped with claws (plus a little dewclaw on a tiny, vestigial fourth toe). T. rex had a slim, stiff, pointed tail that provided balance and allowed quick turns while running. T. rex's neck was short and muscular. Its body was solidly built but its bones were hollow.

SIZE
Tyrannosaurus rex was up to 40 feet (12.4 m) long, about 15 to 20 feet (4.6 to 6 m) tall. The arms were only about 3 feet (1 m) long. Tyrannosaurus rex was roughly 5 to 7 tons in weight.

The enormous skull was about 5 feet (1.5 m) long. The eye sockets in the skull are 4 inches (10.2 cm) across; the eyeballs would have been about 3 inches (7.6 cm) in diameter.

T. rex left footprints 1.55 feet (46 cm) long (although its feet were much longer, about 3.3 feet (1 m) long; T. rex, like other dinosaurs walked on its toes). It had a stride length of up to 12 to 15 feet (3.7-4.6 m). T. rex may have run at up to 15 mph (24 kph).

TEETH AND JAWS

T. rex's jaws were up to 4 feet (1.2 m) long and had 50 to 60 thick, conical, bone-crunching teeth that ranged in size from very small to over 9 inches (23 cm) long. Adult had a variety of sizes of teeth in their jaws at one time, as teeth were broken and new (smaller) ones grew in to replace them. One T. rex was found with some teeth up to 13 inch (33 cm) long. T. rex could eat up to 500 pounds (230 kg) of meat and bones in one bite!

Tyrannosaurus rex had a wrap-around overbite; when T. rex closed its mouth, the upper parts of the lower jaw's teeth fit inside the upper teeth.

SKIN
Fossilized specimens of T. rex's rough, scaly skin have been found. It was bumpy, like an alligator's skin, and has been described as a "lightly pebbled skin."

HABITAT AND DISTRIBUTION
Tyrannosaurus rex probably lived in forests, where its prey (plant-eating dinosaurs) could find plenty of food. T. rex fossils have been found in western North America and Mongolia.

SENSES
Sight: T. rex had large visual lobes in its brain that processed visual information. T. rex also had depth perception (since both eyes faced forwards on the front of its skull, and not placed on the sides), but it was not the only dinosaur that had depth perception. In general, predators (hunters) ofter have depth perception to help them hunt their prey. Animals that are hunted (like the plant-eating dinosaurs) usually have eyes located on the sides of their head (having no depth perception); this lets them see predators approaching from both sides.

Smell: T. rex's brain had a very large area in the brain for processing odors.

TAIL
Tyrannosaurus had a stiff, pointed tail (like other Tetanurans [meaning "stiff tail"]). The tail was used as a counterbalance for its enormous head, for agility and for making quick turns.

The rear part of the tail was stiffened by interlocking vertebral zygopophyses (interlocking bony structures projecting forwards and backwards from the neural arches, interlocking one vertebra into another).

OTHER HUGE MEAT-EATING DINOSAURS
Although not the biggest meat-eating dinosaur ever discovered, Tyrannosaurus rex was certainly one of the largest terrestrial carnivores of all time. The recently discovered Giganotosaurus carolinii and Carcharodontosaurus may have been even more enormous.

SIZE COMPARISONS

PRINTOUTS
A Tyrannosaurus rex printout.

A simple T. rex printout.

A T. rex skeleton printout.

Dinosaur footprint