Mean atmospheric O2
Geologic Time Scale
Ten-foot-long temnospondyl amphibians of the genus Archegosaurus lounge in an Early Permian swamp 285 million years ago in what is today Western Europe. Also in this image are several varieties of fern including tree-like seed ferns of the genus Alethopteris.
Archegosaurus was a large, crocodile-like carnivore that likely fed upon fish and perhaps other amphibians.
Copyright © Walter B. Myers. All rights reserved.
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