Life ‘sprang back quickly’ after worst mass extinction

Fossils of animals including sharks and sea reptiles have challenged scientists' long-held views that life on Earth was slow to recover from the planet's worst mass extinction.

WASHINGTON // Fossils including sharks, sea reptiles and squid-like creatures dug up in Idaho reveal that a marine ecosystem thrived relatively soon after the worst mass extinction on Earth.

That contradicts the long-held notion that life was slow to recover from the calamity.

Scientists last week described the surprising discovery that creatures flourished after the catastrophe at the end of the Permian Period about 251 million years ago, which killed about 90 per cent of all species.

Even the asteroid-induced mass extinction 66 million years ago that doomed the dinosaurs did not push life to the brink of annihilation the way the Permian event did.

The fossils of about 30 different species were unearthed in Bear Lake County near the Idaho city of Paris.

“Our discovery was totally unexpected,” said palaeontologist Arnaud Brayard of the University of Burgundy-Franche-Comte in France.

The ecosystem from this pivotal time included predators such as sharks up to about two metres in length, marine reptiles and bony fish, squid-like creatures, a scavenging crustacean with large eyes and strangely thin claws, starfish relatives, sponges and other animals.

The Permian mass extinction occurred 251.9 million years ago. The Idaho ecosystem flourished 1.3 million years later, “quite rapid on a geological scale”, Dr Brayard said.

The cause of the mass extinction is a matter of debate but many scientists attribute it to colossal volcanic eruptions in northern Siberia that unleashed large amounts of greenhouse and toxic gases. That triggered severe global warming and severe fluctuations in oceanic chemistry, including acidification and oxygen deficiency.

“The Early Triassic is a complex and highly disturbed epoch, but certainly not a devastated one as commonly assumed, and this epoch has not yet yielded up all its secrets,” Dr Brayard said.

The research was published in the journal Science Advances.

* Reuters