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When did eels first appear in Earth’s history?
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eel
The American eel (Anguilla rostrata) is found in habitats along the coast of eastern North America.
Based on studies of fossil evidence and comparative anatomy, eels are believed to have first appeared during the Cretaceous Period, which spanned from approximately 145.5 to 65.5 million years ago. They are thought to have descended from ancestors that shared characteristics with the Elopiformes (such as tarpons) and the Albuliformes (such as bonefishes).1