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 230 million years ago

Mean atmospheric O2
 80% of modern level

Mean atmospheric CO2
 6x pre-industrial level

Mean temperature
 3C above modern level


Mesozoic Earth - A late-Triassic underwater scene from the Panthalassa Ocean featuring a giant Shonisaurus ichthyosaur, Belemnites, an Ammonite, shark, giant clam, small fish, brain coral, columnar coral, staghorn coral and other undersea flora & fauna - Natural History Illustration Geologic Time Scale

 Era: Mesozoic
  Period: Triassic
   Epoch: Middle
    Age: Ladinian



A massive, 30-ton ichthyosaur of the genus Shonisaurus, the largest known marine reptile, attempts to make a meal of a school of squid-like order of cephalopods known as belemnites 230 million years ago. On the far right is a prehistoric shark, and further below is an ancient Ammonite, another squid-like animal with a nautilus-like hard shell.

Panthalassa, the vast global ocean that surrounded the supercontinent Pangaea, was home to the ichthyosaurs, giant air-breathing reptiles that resembled fish and dolphins. Like modern day cetaceans, ichthyosaurs are believed to have evolved from land reptiles that moved back into the water. Ichthyosaurs are notable for having the largest eyes of any land or sea animal. The eye socket of one fossil Shonisaurus skull is over 3 feet in diameter.



Copyright Walter B. Myers. All rights reserved.

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