An artist's impression of a large, active predator called Pentecopterus decorahensis that lived 467 million years ago during the Ordovician Period is shown in this image released on September 1, 2015.... more 
An artist's impression of a large, active predator called Pentecopterus decorahensis that lived 467 million years ago during the Ordovician Period is shown in this image released on September 1, 2015. REUTERS/Patrick Lynch/Yale University/Handout less 
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Reuters | Photo By HANDOUT / Reuters
Tue, Sep 1, 2015 11:23 AM EDT