Extinct species of monk seal discovered in New Zealand

Australian and New Zealand researchers have uncovered an extinct species of monk seal that lived in the Southern Hemisphere, publishing their work in Proceedings of the Royal Society B: Biological Sciences. The discovery has been described as the biggest breakthrough in seal evolution in 70 years, as it radically changes scientists’ understanding of how seal species evolved around the world.

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. Unlike their cold-loving relatives in the Arctic and Antarctic, monk seals typically prefer the warmer waters of the Mediterranean, Hawaii and — until their extinction there in the 1950s — the Caribbean.

Led by Monash University, researchers examined seven preserved monk seal fossil specimens, including a complete skull, found by local fossil hunters on south Taranaki beaches in New Zealand between 2009 and 2016. The new species has been named Eomonachus belegaerensis after the sea of Belegaer, which lies west of Middle Earth in The Lord of the Rings.

Pieces of the fossil specimens discovered.

Measuring around 2.5 metres in length and weighing around 200–250 kg, Eomonachus belegaerensis lived in the waters around New Zealand some 3 million years ago. Its discovery 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,” said Monash palaeontologist and PhD candidate James Rule, who led the new research.

“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.”

James Rule with the complete skull of Eomonachus belegaerensis.

Study collaborator Dr Felix Marx, curator of marine mammals at New Zealand’s Te Papa Museum, said the discovery is 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.”

Dr Marx is hopeful about future discoveries of new species in New Zealand’s ancient past, saying, “New Zealand is incredibly rich in fossils, and so far we have barely scratched the surface. Who knows what else is out there?”

Top image caption: An artist’s impression of Eomonachus belegaerensis. Illustration by Jaime Bran for Te Papa Museum.

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