Scientists have discovered a major extinction event that wiped out around a third of marine species and reduced their diversity by 55% between two to three million years ago.

The disappearance of a large part of the terrestrial megafauna such as the sabre-toothed cat and the mammoth during the Ice Age is well known.

Researchers at the University of Zurich in Switzerland and the Naturkunde Museum in Berlin have shown that a similar extinction event had taken place earlier in the oceans.

The team investigated fossils of marine megafauna from the Pliocene and the Pleisto-cene epochs — 5.3 million to around 9,700 years B.C.

Diversity hit

“We were able to show that around a third of marine megafauna disappeared about three to two million years ago. Therefore, the marine megafaunal communities that humans inherited were already altered and functioning at a diminished diversity,” said Catalina Pimiento from the University of Zurich.

As many as 43% of sea turtle species were lost, along with 35% of sea birds and nine per cent of sharks.