They suffered greatly during the last three of five great Phanerozoic dyings-latestPermian, latest Triassic, and latest Cretaceous.
2
Sometimes too you will see the term Phanerozoic used to describe the span encompassing the Cenozoic, Mesozoic, and Paleozoic eras.
3
They build upon work done by Sloss by applying statistical methods to the Phanerozoic (past 550 million years) sedimentary rock record of North America.