An old fossil in Germany. Getty images

Plesiosaurs were giant, four finned, and fierce looking marine carnivores that roamed the waters of Antarctica 150 million years ago. Now, a team of researchers from Argentina found the remains of this prehistoric beast.

Measuring up to 12 meters in length, this reptile was an imposing predator. It roamed the Earth during the late Jurassic period and is now the most ancient creature ever discovered on the icy continent.

Paleontologist José Patricio O'Gorman, the researcher at the Museo de la Plata (MLP) and CONICET, commented that "this record of plesiosaurus is 80 million years older than what was known for Antarctica," in a report by Agencia Ty-UNLaM.

"It was the first paleontological campaign that we carried out in this outcrop that is like a frozen sea of 150 million years in an excellent state of conservation," said the main author of the study that was accepted to be published in the scientific journal Comptes Rendus Palevol.

The site where the remains were discovered is a two-hour helicopter journey from Argentina's Marambio Base on the tip of Antarctica.

The team of researchers from the University of La Matanza near Buenos Aries was pleasantly surprised because they knew that Antarctica's harsh climate is not conducive to the preservation of fossils or animal remains of any kind.

"The discovery is pretty extraordinary because the rock types at the site weren't thought conducive to the preservation of bones, like the vertebrae of this marine reptile," Soledad Cavalli, a paleontologist at the University of La Matanza said in a Phys report.

During the time when the animal lived, the continents were not as fragmented as they are now. Before the continental drift, Australia, New Zealand, India, Madagascar, Antarctica, Africa, and South America were all a part of a larger landmass known as the Gondwana continent.

Plesiosaur were fascinating creatures. A report by International Business Times recently said that a study found out that the plesiosaur used to move not by swimming like sharks or whales but flew underwater, much like modern-day Penguins and sea turtles.

The team of paleontologists from the University of Bonn, Germany, with colleagues from Japan and France found that the oldest plesiosaur species ever discovered, moved through this unique form of underwater propulsion.

The oldest plesiosaur species comes from the youngest part of the Triassic period and is about 201 million years old.

Plesiosaurs figured out a more efficient way to expend energy while swimming was by gliding instead of furiously pushing water with their modified limbs which they started using like birds use their wings during flight.

Their body structure also enabled them to move in a unique way only a few modern-day aquatic animals and birds possess. They had a very small head compared to their long, streamlined neck. They had a very stout body with strong muscles that helped acquire this new movement pattern that we see even today.