Mean atmospheric O2
Geologic Time Scale
Primitive lungfish (fish equipped with rudimentary lungs as well as gills) of the genus Dipterus emerge from a Late Devonian fresh water lake 385 million years ago in what is today North America. Large terrestrial flora include varieties of lycopods and tree-like plants of the genus Archaeopteris dominate the landscape. The underbrush suggests how younger versions of these plants may have appeared, however it's not necessarily representative of any specific flora.
Dipterus were among the first vertebrates to venture from aquatic environments, though they were not ancestors of the earliest tetrapods which appeared some 20 million years later.
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