The dinosaur book - the ruling reptiles and their relatives (1951) (20374264636)

Title: The dinosaur book : the ruling reptiles and their relatives
Identifier: bookruli00colb (find matches)
Year: 1951 (1950s)
Authors: Colbert, Edwin H. (Edwin Harris), 1905-2001; Knight, Charles Robert, 1874-1953; American Museum of Natural History
Subjects: Dinosaurs; Reptiles, Fossil
Publisher: New York : Published for the American Museum of Natural History by McGraw-Hill
Contributing Library: American Museum of Natural History Library
Digitizing Sponsor: IMLS / LSTA / METRO



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oughly aquatic reptiles, adapted to a diet of mollusks and other shellfish, for their skulls and jaws were equipped with broad, flat crushing teeth. The paddles were relatively weak, so these animals must have been slow swimmers. Why should they need to swim rapidly, since their days were spent coasting along the bottom of shallow waters, picking up the Mesozoic brethren of our modern oysters, which were virtually stationary? There may have been some aquatic enemies to bother Placodus and his relatives; if so these predators would find the placodonts rather tough eating. For Placodus had heavy dorsal ribs and a strong "basket" of abdominal ribs that offered considerable protection to the body, while a related form, Placochelys (plak-o- KEEL-is), was covered turtle-fashion with a strong shell. The Mosasaurs The ichthyosaurs, plesiosaurs, and their relatives were the inhabitants of the waters in Mesozoic times. They ruled the open seas and the large lakes, where fish and mollusks abounded and where the great land-living dinosaurs were curious objects to be seen upon a distant shore. Yet abun- dant as they were, the parapsids and euryapsids had to share their dominance of the water with certain other Mesozoic rep- tiles. Of these, the most numerous and The giant mosasaur Tylosaurus, of the Cretaceous seas of western North America Restoration by Charles R. Knight
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