The ancient fossils found on Seymor Island in the Antarctic belong to the largest elasmosaurus on record (Credit: Nobu Tamura/CC BY-SA 3.0 /

Fans of Scotland's mythical Loch Ness Monster, or Nessie, will be thrilled by the discovery of the remains of a massive look-alike elasmosaurus. Measuring 36 feet long (11 meters), from snout to tail, it is the largest specimen of the four-flippered sea giants — which inhabited Earth between 55 to 66 million years ago — on record.

"Not only is it quite long, it's also quite stocky and weighed nearly 15 tons (13.4 metric tons) when it was alive, making it the heaviest-known elasmosaurid," said study lead researcher José O'Gorman, a vertebrate paleontologist at the La Plata Museum and the National University of La Plata in Argentina. Before the latest find, the ancient marine animal's heaviest specimen discovered weighed 5 tons!

It took paleontologists 20 years to unearth the massive elasmosaurus from its rocky grave (Credit:
Agencia CTyS-UNLaM)

The elasmosaurus, which lay undisturbed on Antarctica's Seymor Island for centuries, was first discovered in 1989 by Dr. William Zinsmeister, a professor at Indiana's Purdue University. Lacking the resources to unearth the fossil, he informed the Argentina Antarctic Institute about the discovery. But the beast's size and rocky bed made it impossible for the South American paleontologists to extract the remains in a single expedition. Also, the digs, which could only be conducted in January and February during the Antarctica "summer," did not happen some years due to weather conditions and limited resources. It was not until 2017 that the researchers finally managed to excavate the massive creature's almost complete skeleton and begin a detailed analysis.

Elasmosauridae lived on Earth during the late Cretaceous period (Credit: Slate Weasel /Public domain/

The paleontologists, whose study will be published in the journal Cretaceous Research in October 2019, believe the elasmosaurus falls under the genus Aristonectes. However, since its bones do not overlap with any others discovered, they are not sure if it's a new species. The creature, whose fused vertebrae indicate it was a fully grown adult, likely feasted on invertebrates, such as jellyfish. O'Gorman suspects it probably lived 30,000 years before the mass extinction, which killed all non-avian dinosaurs, about 66 million years ago. The researcher says its huge size indicates that, while it was alive the ecosystem was flourishing with plenty of tasty prey for the sea monster to devour.

Part of the plesiosaur family, elasmosaurids were the largest sea creatures to inhabit Earth during the late Cretaceous era, an interval of geological time from about 55 to 66 million years ago. They had trim torsos, four flippers, and small, snake-like heads. The ancient monster's most distinguishing feature, however, was its long giraffe-like neck, which comprised up to 71 vertebrae. Scientists suspect the elongated necks helped the marine animals, who lacked gills, to easily emerge above water to breathe. They believe that, similar to whales, elasmosaurids fed by opening their mouths wide to capture as much of the unsuspecting small prey floating around as possible.

A Reconstructed skeleton of an elasmosaurus skeleton at Milwaukee Public Museum (Credit: Evan Howard /CC BY-SA 2.0/

This is not the first time paleontologists have discovered dinosaur-era fossils in Antarctica. Previous discoveries include the first plesiosaur bones, remains of the duck-billed hadrosaur, and even evidence of ancient trees dating back 100 million years!