New dates raise questions about the extent of the Great Dying
BALTIMORE — The greatest extinction in Earth’s history might not have been so great after all. A suspected colossal die-off of roughly 75 percent of land species didn’t accompany the Permian extinction around 252 million years ago, a team of geologists contend.
That divisive result comes from new work in South Africa that redates the demise of Dicynodon — a mammal relative whose disappearance defines the terrestrial extinction event in the rock record. The new timeline places the creature’s disappearance at more than a million years before the Permian extinction in the ocean, in which 90 percent of marine species vanished.
Furthermore, the researchers argue, the new evidence raises doubts that a mass extinction on land even happened at all.
Although many experts are not convinced, the established understanding of the Permian extinction is &ldquo