<span class="SFPTagline"> From SCIFIPEDIA </span>

A dinosaur is a reptile of the Mesozoic Era. Dinosaurs are the largest known land animals. The first dinosaur fossil was Megalosaurus, identified and described by William Buckland in 1824, with more than 500 species identified by the scientific community since then. Paleontologists, who study the forms of life existing in former geologic periods represented in the fossil records, believe there could be 1,850 or more species of dinosaur. The reign of the dinosaurs lasted for over 165 million years, only to come to a mysterious close approximately 65 million years ago.

The Mesozoic Era includes the Triassic period, the Jurassic period, and the Cretaceous period. The oldest dinosaur fossils so far have been found on Madagascar, and date from the Triassic period (about 230 million years ago).

The biggest dinosaurs were gigantic, slow-moving sauropods (plant-eaters) from the late Jurassic and Cretaceous periods. Examples are the Diplodocus and Brachiosaurus, which could weigh up to 80 tons. The biggest carnivorous dinosaurs were theropods from the Cretaceous period, including the ever-popular, six-ton Tyrannosaurus rex, found in North America.

Related Terms and Articles

• Living Dinosaurs

External Links

• Smithsonian Institute on Dinosaurs

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