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Dinosaur

fossil reptile
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External Websites
  • USGS - Dinosaurs: Facts and Fiction
  • American Musem of Natural History - Dinosaurs
  • DesertUSA - Dinosaur
  • University of California Museum of Paleontology - The Dinosauria
  • National Geographic - Science - Dinosaurs—Flesh and Bone
  • LiveScience - A Brief History of Dinosaurs
Britannica Websites
Articles from Britannica Encyclopedias for elementary and high school students.
  • dinosaur - Children's Encyclopedia (Ages 8-11)
  • dinosaur - Student Encyclopedia (Ages 11 and up)
Alternative Title: Dinosauria
Below is the full article. For the article summary, see Dinosaur summary.

Dinosaur, (clade Dinosauria), the common name given to a group of dinosaurs to scale

dinosaurs to scale
A selection of dinosaurs grouped by the geologic interval in which they lived.
Encyclopædia Britannica, Inc.
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The name dinosaur comes from the Greek words deinos (“terrible” or “fearfully great”) and sauros (“reptile” or “lizard”). The English anatomist Richard Owen proposed the formal term Dinosauria in 1842 to include three giant extinct animals (Megalosaurus, Iguanodon, and Hylaeosaurus) represented by large fossilized bones that had been unearthed at several locations in southern England during the early part of the 19th century. Owen recognized that these reptiles were far different from other known reptiles of the present and the past for three reasons: they were large yet obviously terrestrial, unlike the aquatic ichthyosaurs and plesiosaurs that were already known; they had five vertebrae in their hips, whereas most known reptiles have only two; and, rather than holding their limbs sprawled out to the side in the manner of lizards, dinosaurs held their limbs under the body in columnar fashion, like elephants and other large mammals.

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The search for dinosaurs

The first finds

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