Spiky-Headed Sharks Survived Mass Extinction, Surprising Scientists
An exotic, ancient shark thrived into the age of dinosaurs, study says.
Some 252 million years ago, roughly 90 percent of the planet's marine species perished in the Permian-Triassic mass extinction event.
Tied to everything from volcanic eruptions to ocean oxygen depletion to severe climate change, the Great Dying represents the most severe challenge to life's survival seen in the fossil record. (See "The Permian Extinction—When Life Nearly Came to an End.")
Among the victims were thought to be a wide variety of early cladodont sharks. These sharks—which brandished long, sharp, T-shaped teeth—are today seen as vanished, unsuccessful cousins of modern broad-toothed sharks.
However, an international team led by Switzerland's Guillaume Guinot of the Natural History Museum in Geneva, reports in the journal Nature Communications that the sharks survived
