Researchers have found a new species of extinct monk seal which lived in the Tasman Sea around New Zealand.

The new species is named Eomonachus belegaerensis - a reference to the fictional ‘Great Sea’ Belegaer from J.R.R. Tolkien’s The Lord of the Rings.

Monash University researchers described it as the biggest breakthrough in seal evolution in 70 years.

The discovery radically changes scientists’ understanding of how seal species evolved around the world.

The discovery was made after researchers examined seven preserved fossil specimens, including a complete skull, found by local fossil hunters on south Taranaki beaches in New Zealand between 2009 and 2016.

Eomonachus belegaerensis lived in the waters around New Zealand some 3 million years ago.

It was previously thought that all true seals originated in the North Atlantic, with some later crossing the equator to live as far south as Antarctica.

Eomonachus now shows that many ancient seals, including the ancestors of today’s monk, elephant and Antarctic seals, actually evolved in the Southern Hemisphere.

“This new species of extinct monk seal is the first of its kind from the Southern Hemisphere. Its discovery really turns seal evolution on its head,” says Monash palaeontologist James Rule, a PhD candidate at the Biomedicine Discovery Institute.

“Until now, we thought that all true seals originated in the Northern Hemisphere, and then crossed the equator just once or twice during their entire evolutionary history. Instead, many of them appear to have evolved in the southern Pacific, and then criss-crossed the equator up to eight times.”

Te Papa Museum of New Zealand curator of marine mammals and study collaborator Dr Felix Marx said the discovery was a triumph for citizen science.

“This new species has been discovered thanks to numerous, exceptionally well-preserved fossils – all of which were found by members of the public.”

The study is accessible here.