 |
| I n t r o d u c t i o n | ||||
 Tyrannosaurus
rex, at left, faces off against Spinosaurus in "Jurassic
Park III." The movie is highlighting a “rising star”
of the dinosaur world called Spinosaurus, even though in real
life it never encountered T. rex. Tyrannosaurs ruled the earth
30 million years after Spinosaurus' heyday. |
The
Dinosaurs are extinct reptiles that lived from about 230 million to
about 65 million years ago. The word dinosaur was coined in 1842 by
British anatomist Sir Richard Owen, derived from the Greek words deinos,
meaning “marvelous” or “terrible,” and sauros,
meaning “lizard.” For more than 140 million years, dinosaurs
reigned as the dominant animals on land. Owen distinguished dinosaurs from other prehistoric reptiles by their upright rather than sprawling legs and by the presence of three or more vertebrae supporting the pelvis, or hipbone. The first dinosaurs studied by paleontologists were Megalosaurus and Iguanodon, whose partial bones were discovered early in the 19th century in England. The shape of their bones indicates that these animals resembled large, land-dwelling reptiles. The teeth of Megalosaurus, which are pointed and have serrated edges, indicate that this animal was a flesh eater, while the flattened, grinding surfaces of Iguanodon teeth indicate that it was a plant eater. Megalosaurus lived during the Jurassic Period, and Iguanodon lived during the early part of the Cretaceous Period. Later in the 19th century, paleontologists collected and studied more complete skeletons of related dinosaurs found in New Jersey. From these finds they learned that Megalosaurus and Iguanodon walked on two legs, not four, as had been thought. |
|||