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When did the Mesozoic Era begin and end?
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geologic history of Earth
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The Mesozoic Era, often referred to as the age of the dinosaurs, began 252.2 million years ago and ended 66 million years ago.1
It serves as the second of three major geologic eras within the Phanerozoic Eon, following the Paleozoic Era and preceding the Cenozoic Era. The era is divided into three distinct periods: the Triassic Period, the Jurassic Period, and the Cretaceous Period.1