Place of discovery : University of Chile/PA Wire

Antarctica was once home to a 10-metre long sea monster that hunted the reptilian equivalent of whales at the end of the dinosaur age, scientists have discovered.

The mosasaur, a huge marine lizard with fearsome jaws and paddle-like limbs, lived 66 million years ago when Antarctica was much warmer than it is today.

A 1.2m long skull of one of the beasts was unearthed on Seymour Island off the Antarctic peninsular in 2010.


Scientists describing the find named the creature Kaikaifilu hervei, after a giant sea reptile featured in a native creation myth.

In the tradition of the Mapuche people from southern Chile and Argentina, the battle between Kai-Kai filu and his great rival, another demi-god reptile that ruled the land, shaped the world.

Kaikaifilu was the largest southern hemisphere mosasaur discovered to date.

It was about twice the size of the biggest creature of this type previously found in Antarctica, which had a skull 70cm long.

Hunting ‘whales’

The creature’s main prey was probably aristonectine plesiosaurs, long-necked marine reptiles that filter-fed in much the same way as present-day baleen whales.

Both Kaikaifilu and dinosaurs such as Tyrannosaurus rex lived at the end of the Cretaceous period and vanished in the great extinction event that followed a giant meteor impact off the coast of Mexico.

“Prior to this research, the known mosasaur remains from Antarctica provided no evidence for the presence of very large predators like Kaikaifilu, in an environment where plesiosaurs were especially abundant,” says study author Rodrigo Otero, from the University of Chile.

“The new find complements one expected ecological element of the Antarctic ecosystem during the latest Cretaceous.”

Journal reference: Cretaceous Research, DOI: 10.1016/j.cretres.2016.11.002

Correction [9 November 2016]: We have changed the headline to better reflect the mosasaur’s prey.