Lazarus effect
n.β Β«To reappear after 11 million years is more exciting than if the rodent really had been a new species…Indeed, such reappearances are so rare that paleontologists dub them “the Lazarus effect.”Β» ββA rodent from the past” in D.C. Toronto Sun (Canada) Mar. 10, 2006. (source: Double-Tongued Dictionary)