Title: Animal biology
Identifier: animalbiology1940wolc (find matches)
Year: 1940 (1940s)
Authors: Wolcott, Robert Henry, 1868-1934; University of Nebraska (Lincoln campus). Dept. of Zoology
Subjects: Zoology; Biology
Publisher: New York ; London : McGraw-Hill Book Company, Inc.
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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PAST DISTRIBUTION OF ANIMALS 543 which is known as the age of fishes. The more modern fishes, the teleosts, were not known until the Jurassic and are represented now by the greatest number and diversity of species they have ever possessed. A footprint from the Devonian is the earUest trace of an amphibian. There were giant armored amphibians, the Stegocephala, in the Pennsylvanian and Permian periods. These reached a maximum length of 15 to 20 feet in the Triassic, when they became extinct. The reptiles appeared about the time of the amphibians but did not become dominant until the Mesozoic, which was the age of reptiles; they reached their highest development during the Jurassic. The aquatic and marine types attained a length of 40 feet; a flying pterodactyl had a wing spread of 25 feet; and the gigantic dinosaurs reached 100 feet in length. These giants suddenly became extinct in the Cretaceous.
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Fig. 375.—Archidiskodon maiheni Barbour, one of the largest skeletons of a mammoth on record—14 feet at the shoulder—in comparison with the skeleton of a recent Indian elephant and with the two men standing under it. (Photographed from a specimen in the University of Nebraska State Museum.) Fossil remains of the earliest bird, Archaeopteryx (Fig. 297), have been found in the Jurassic slates of Bavaria, and a number of other birds are known from the Cretaceous. The earliest mammalian remains are from the upper Triassic, and many types are known from the Creta- ceous. Mammals have been dominant since the beginning of the Cenozoic era. Human origins have already been discussed. Steps in the development of other mammalian types will be referred to in the next chapter, on evolution.

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