Fossils found in New Zealand have led to the discovery of a previously unidentified species of extinct monk seal, which biologists say is the biggest breakthrough in seal evolution in seven decades.
The animal – named Eomonachus belegaerensis – was named after a sea in JRR Tolkien’s the Lord of the Rings, and has radically changed scientists’ understanding of how seal species have evolved around the world.
Eomonachus belegaerensis lived in the waters around New Zealand some three million years ago, and was 2.5 metres in length and weighed around 200-250kg.
Monash University palaeontologist James Rule, a PhD candidate in the Department of Anatomy and Developmental Biology, worked with a team of Trans Tasman scientists on his paper.
“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,” Rule said.
“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.”
The equator usually acts as a barrier for marine animals crossing, Rule said, as the waters are so warm, so the discovery that seals crossed numerous times over their evolutionary history is significant.
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 shows that many ancient seals, including the ancestors of today’s monk, elephant and Antarctic seals, actually evolved in the southern hemisphere.
Dr Felix Marx, Te Papa Museum of New Zealand’s curator of marine mammals, said the discovery was a triumph for citizen science, as the fossils studied by the Monash team were collected by beach-goers in Taranaki between the years 2009-2016.
“This new species has been discovered thanks to numerous, exceptionally well-preserved fossils – all of which were found by members of the public,” Marx said.
“New Zealand is incredibly rich in fossils, and so far we have barely scratched the surface.”
Rule says now ancient monk seals have been discovered in New Zealand, it makes the research possibilities for all of the south Pacific much more urgent.
Traditionally the southern hemisphere is under-researched compared to the northern hemisphere, Rule said.
“I would like to see if there’s any monk seals to be found in Australia. Also, now that New Zealand has produced a monk seals I want to look for other seals [in NZ] that would be completely unexpected.”