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 365 million years ago

Mean atmospheric O2
 75% of modern level

Mean atmospheric CO2
 8x pre-industrial level

Mean temperature
 6C above modern level


Paleozoic Earth - A close-up of a Late Devonian Ichthyostega featuring a Rhacophyton ceratangium (R-rhacophyton), prehistoric roaches and a millipede; Famennian stage; missing link; tetrapod; paleontology; paleobiology; paleobotany - Natural History Illustration Geologic Time Scale

 Era: Paleozoic
  Period: Devonian
   Epoch: Late
    Age: Famennian


Ichthyostega portrait

Close-up of a three-foot-long tetrapod of the genus Ichthyostega 365 million years ago in what is today the Canadian Arctic. Flanking the Ichthyostega are Rhacophyton ceratangium, a species of unclassified ancient shrub that are thought to be one of the earliest ferns. The reddish fruit-like nodules attached to the fronds on the right are sporangia, enclosures in which spores are formed. The large tree-like trunk on the far left is the base of a young Archaeopteris.

In the foreground are prehistoric arthropods--a millipede on the left and on the right "roachoids" on trunk of a decaying Lycopsid. Arthropods had been walking the Earth for 40 million years before vertebrates like Ichthyostega began venturing ashore.

Ichthyostega was one of the earliest tetrapods, a descendent of lobe-finned fishes and ancestor of amphibians. Ichthyostega had lungs and seven-toed limbs that allowed it to move about the shallow waters and shores of swamps and floodplains. It was among the first terrestrial vertebrates.



Copyright Walter B. Myers. All rights reserved.

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