The fossils that rewrite the history of the monk seal

Monk seals live in the warm waters of the Mediterranean and the Hawaiian Islands, where only about 2,000 individuals survive.

They are part of the group called "true seals": they do not have ears and move by crawling on their stomach when they are on land, unlike sea lions and wolves (which can walk).

Until now, the scientific community believed that the origin of monk seals was located in the Atlantic Ocean, in the northern hemisphere.

But the discovery of seven skull fossils off the coast of New Zealand has rethought the evolutionary theory of this animal.

A team of paleontologists from Australia and New Zealand have studied these fossils for four years and discovered that they belong to monk seals that lived in the Antipodes about three million years ago.

They are the first vestiges of this species found in the southern hemisphere.

Leading the team is marine mammal expert from Monash University (in Melbourne, Australia) James Rule.

"It is not very often that the evolution of a large group of mammals is completely rewritten," explains Rule, whose work has been published in the journal

.

"The research completely turns around the way we understood evolution: we believed that monk seals and their relatives had evolved in the north, but this study shows that they actually originated in the southern hemisphere," he says.

Rule admires the

films

that were shot in New Zealand, a story that inspired him to choose the scientific name of the seal specimens discovered.

From now on they will be known as

, which translates as the monk seal of dawn in Belegaer (the ocean located in the west of Middle-earth in the novels of JRR Tolkien).

But the story of how the fossils were found does not seem to be taken from a fantastic novel, but is the fruit of years of work and dedication by a group of citizens who are fond of paleontology.

It was they who found the seal skulls off the coast of Taranaki (on the north island of New Zealand) between 2009 and 2016 and gave the fossils to two of the most important museums in the country: the Canterbury Museum and the Museum of Te Pope in Wellington.

Felix Marx, the curator of marine mammals at Te Papa, describes it as a "triumph of citizen science", as these fossils are preserved within large rocks on the beach: "There is a group of very enthusiastic local collectors who have been they are dedicated to it, and we have been following the discoveries they have made in recent years and have been able to analyze them.

So they are the ones who have the local knowledge and the desire to go find these fossils.

It is something we could do ourselves, but it would take us much longer and we would be less successful because we can only go there once a year, whereas these locals visit the area sometimes every fortnight. "

According to Marx, discoveries like this show that the Southern Hemisphere is much less explored than the Northern Hemisphere, where historically there have been more Universities, experts and resources devoted to finding fossils.

That is why he hopes that in the future countries such as Australia and New Zealand will offer more paleontological discoveries of such magnitude.

“In recent decades the southern hemisphere has been catching up, but there are entire areas where we have only scratched the surface.

I think New Zealand is one of them.

There are entire periods in Earth's history that we surely have material from in New Zealand, but no one has been able to study it yet. "

Analysis of the fossils found at Taranaki concludes that the ancient specimens were about 2.5 meters long and weighed between 200 and 250 kilos, and were similar to the monk seal that currently lives in Hawaii.

To reach this conclusion, paleontologist James Rule traveled for two years to compare the remains found in New Zealand with the seal fossils found in the Natural History Museums in London, Paris or Los Angeles.

It was at the Smithsonian Museum in Washington, when he was in front of a group of monk seal skulls, that he discovered to his surprise that he was holding remains that belonged to the same species.

Rule hopes that his discovery will serve as a "cautionary tale" regarding the state of conservation of this animal today.

"Today monk seals are the most endangered seals on the planet," he warns.

“What this finding indicates is that these seals had a much wider geographic range in the past, they were found in the Northern and Southern hemispheres.

But the seals we have today are the last ones left.

Their survival is hanging by a thread, human intervention has not helped and this finding shows that they are at higher risk of extinction than other seals.

We should take care of them. "

According to paleontologists, three million years ago there was a climate change in the oceans that affected the largest marine animals such as whales, dolphins and seals.

Temperatures dropped and with them sea level, a phenomenon that could be behind the extinction of monk seals in the Southern Hemisphere.

Scientists now fear that the opposite phenomenon, global warming, threatens the decimated monk seal population.

The increase in temperatures makes it more difficult for these seals to find food and the rise in sea level causes the disappearance of the beaches they need to rest and reproduce.

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