'Previously unknown extinction' discovered

Modern sea turtles replaced the megafauna. Credit: Stefan Sauer/DPA/PA Images

Over two million years ago, a third of the largest marine animals including the largest shark to have ever lived, Megalodon, whales, sea birds and sea turtles disappeared.

Scientists say this previously unknown extinction event not only had a considerable impact on the earth’s historical biodiversity but also on the functioning of ecosystems. This has been demonstrated a team of researchers, including co-author Dr John Griffin of Swansea University’s Department of Bioscience.

The disappearance of a large part of the megafauna on land like sabre-toothed cat and the mammoth during the ice age is well known. Now, the team of researchers led by the University of Zurich, and the Natukunde Museum in Berlin say they have shown that a similar extinction event had taken place earlier, in the oceans.

It’s astonishing that an extinction event like this, among the biggest animals in the oceans, could go undetected until now. It overturns the assumption that the oceans’ biodiversity was resistant to environmental change in Earth’s recent history.

Dr John Griffin, Swansea University

The extinction is being put down to environmental changes.

The researchers also point to a present-day parallel. They say nowadays, large marine species like whales or seals are highly vulnerable to human influences.