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Untitled 13 Mar 2010 
Saturday   06:26:42 
Untitled Ecosystems
Topics & Issues
Taxonomy
Animals
Birds
Plants
Internet Resources
Regions of the World Untitled
Dinosaurs
Dino Timeline
Types & Classification
Dino Myths & Misconceptions
Museums & Galleries
Dino Quiz
Photogallery & Links Untitled
Navigating Ecosystems
Ecosystems

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Dinosaurs
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Dinosaur Groups

Dinosauria includes animals whose bodies were built around two very different pelvic structures. Accordingly, Dinosauria is divided into two major groups:
  • Untitled Saurischia ("Lizard-hipped" or "Reptile-hipped")
    The Untitled Saurischia dinosaurs were prevalent during the Triassic Period (about 245 million-210 million years ago) and the Jurassic Period (about 210 million-145 million years ago).
  • Untitled Ornithischia ("Bird-hipped")
    The Untitled Ornithischia dinosaurs were prevalent during the Cretaceous Period (about 145 million-65 million years ago).
Untitled Saurischia and Untitled Ornithischia dinosaurs further branch into major subgroups, based on their distinctive body appearance and eating behavior. A complete list of the major groups is shown below. [Click on the underlined abbreviations to learn more about their characteristics and various species of dinosaurs in each group.]

Classification of Dinosauria SI

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      First Written: 19990104       Latest Update: 20060328 Untitled
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