File:The dinosaur book - the ruling reptiles and their relatives (1951) (20374167956).jpg

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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FROM THIS SORT OF PATTERN, all of the varied dinosaurs developed: the skeleton of Saltoposuchus, a Triassic thecodont rep- tile only about four feet long Modified from von Hume specialized in an interesting manner. These were the reptiles known as the phytosaurs jy (FiTE-o-sawrs), which, like all thecodonts, lived in Triassic times. The phytosaurs are found in various parts of the earth, particu- larly in Europe, Asia, and North America. \ Whereas the primitive thecodonts were small, the phytosaurs were rather large, ranging in size from six to 20 feet or more in length. And while the primitive theco- donts were mostly two-footed, the phyto- saurs were four-footed. It is perhaps sig- nificant, however, that even in these four- footed phytosaurs, the front limbs were noticeably smaller than the hind limbs. The return of the phytosaurs to the primi- tive four-footed mode of life was only one phase of their adaptation, for these were semi-aquatic reptiles. They lived a croco- dile-like existence in the streams and lakes of the Triassic landscape, spending most of their time in the water, preying upon such hapless animals as might come within their reach, and crawling out on the sandy bars and banks to sun themselves. The phytosaurs had a very crocodile-like ap- pearance, not only in the body but also in the head itself; indeed, to a casual eye, the skeleton of a phytosaur might easily be mistaken for one of a crocodile. The most noticeable difference is that in the phyto- saur the nostrils are located on the top of the head, immediately in front of the eyes, lather than at the tip of the snout as they are in the crocodiles. It should be empha- sized here that in spite of this similarity of appearance between the phytosaurs and the crocodiles, they were quite distinct groups of reptiles. The phytosaurs were not the ancestors of the crocodiles. Here is a prime example of parallelism in evolution,—the similar development of distinct but related animals. The phytosaurs were like crocodiles, at a time when croco- 62

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