Dinosaurs: Ancient Fossils, New Discoveries California Academy of Sciences Dinosaurs - Ancient Fossils, New Discoveries

Field Guide

T. rex
© 2005 The Field Museum, GN89907c, Painting by John Gurche

T. rex
Pronunciation: "Tie-RAN-uh-sore-us rex"
Length: 12 meters (40 feet)
Height: 3.6 meters (12 feet)
Weight: 5,000-7,000 kg (about 11,000-15,500 pounds)
Food: Other animals
Lifespan: About 28 years
When it lived: 99-65.5 million years ago
Fun fact: At the hip, this adult T. rex is three times the height of an average seven-year old—but more than 260 times the weight of that child!


CicadaCicadidae (cicada; model based on:)
Early Cretaceous, Barremian (130.0-125.5 million years ago)
Yixian formation, Liaoning, China
Peking University, Beijing



Coelophysis bauri Coelophysis bauri
Pronunciation: "seal-o-FYE-sis BORE-eye"
Length: between two and three meters (about 6-10 feet)
Weight: about 45 kilos (100 pounds)
Food: small reptiles and fish
When it lived: about 215 million years ago
Fun fact: In Coelophysis trackways the prints are often widely spaced. Perhaps these animals were often in a hurry.



PsittacosaurusPsittacosaurus mongoliensis
Pronunciation: "sih-TACK-oh-sore-us mon-go-lee-EN-sis"
Length: 130 centimeters (4 feet)
Height: 60 centimeters (2 feet)
Food: plants
When it lived: 100 million years ago
Fun fact: This dinosaur was named for its beak: Psittacosaurus means "parrot reptile."



Protoceratops Protoceratops
Pronunciation: "pro-toe-SAIR-uh-tops"
Length: around 2 meters (7 feet)
Height: 1 meter (3 feet)
Weight: 180 kilograms (400 pounds)
Food: plants
When it lived: 80–85 million years ago
Fun fact: Fossils of baby Protoceratops have been found together, suggesting that parents might have taken care of their young.



AnchiceratopsAnchiceratops ornatus
Pronunciation: "ank-ee-SAIR-uh-tops oar-NAY-tus"
Length: 6 meters (20 feet)
Weight: probably 1 ton or more
Food: plants
When it lived: 70 million years ago
Fun fact: Anchiceratops seems to have preferred low-lying, marshy habitats.



Stegosaurus Stegosaurus
Pronunciation: “steg-oh-SORE-us”
Length: 9 meters (30 feet)
Height: 4 meters (12 feet)
Weight: up to 2 tons
Food: plants
When it lived: 150 million years ago
Fun fact: Stegosaurus had sharp spikes on its tail, which may have been used as weapons against attackers.



Sinosauropteryx prima Sinosauropteryx prima
Pronunciation: "sigh-no-sore-AHP-ter-ix PREE-ma"

Birdlike dinosaur with short, featherlike fibers on body.

The fossil remains of Sinosauropteryx provided the first evidence that animals other than birds had a featherlike covering. But this dinosaur was not covered in feathers as we know them today.

Instead Sinosauropteryx had a coating of thin, hollow filaments on its body. These primitive feathers may have served to keep the animal warm, much as hair does on mammals.



Confusciousornis sanctusConfuciusornis sanctus
Pronunciation: "con-FEW-shis-or-nis SANK-tus"

Flying bird; one sex had long tail feathers, which may have been used in mating displays.

Birds like Confuciusornis evolved from an early feathered dinosaur. This diorama shows birds and other feathered dinosaurs living at the same time. How can this be?




Caudipteryx zoui
Pronunciation: "caw-DIP-ter-ix ZJO-eye"

Birdlike dinosaur with feathers covering whole body. Long, striped tail plume.

The feathers on Caudipteryx are very similar to those of modern birds. The feathers have a central hollow shaft with numerous thin filaments (called barbs) extending outward, creating the recognizable shape of a feather. Yet even though Caudipteryx had feathers like modern birds, it did not fly because its arms were too short. Modern feathers evolved long before the ability to fly.



Dilong paradoxusDilong paradoxus
Pronunciation: "dee-LONG pair-uh-DOX-us"

Feathered tyrannosaur with short, thin featherlike fibers on body. Relatively long arms with three-fingered hands.

A relative of T. rex sporting feathers might seem surprising, but scientists actually expected to find a feathered tyrannosaur one day. Tyrannosaurs are classified as advanced theropods (theropods are two-legged, meat-eating dinosaurs). Scientists have found simple feathers on a wide range of advanced theropods, suggesting that feathers were present throughout the entire group.



water striderGerridae (water strider; model based on:)
Early Cretaceous, Barremian (130.0-125.5 million years ago)
Yixian formation, Liaoning, China
Peking University, Beijing

Return to top

» Teacher Resources
» Kids Stuff