The gigantic ‘sea monster’ whose skull was found – 12/11/2023 – Science

The skull of a colossal marine animal has been extracted from the cliffs of the Jurassic coast of Dorset in southern England.

It belongs to a pliosaur, a ferocious underwater reptile that terrorized the oceans around 150 million years ago. One of the scientists responsible for the discovery said that the fossil is like a kind of “underwater tyrannosaur” — given its dimensions and predatory characteristics.

The two-meter-long fossil is one of the most complete of its kind ever discovered and could provide new clues about this ancient predator.

There is no other animal that compares to it, believes paleontologist Steve Etches.

“It’s one of the best fossils I’ve ever worked with. What makes it unique is that it’s complete,” he tells BBC News.

“The lower jaw and upper part of the skull are interconnected, as they would be if he were alive.”

“Around the world, there are almost no fossils found with this level of detail. And if they are, there are many pieces missing, while this one, although slightly deformed — has all the bones present”, he adds.

The skull is longer than most humans, which gives an idea of ​​the creature’s size.

It’s impossible not to pay attention to its 130 teeth, especially the back ones.

Long and sharp, they could kill with a single bite. But all it takes is a closer look to notice that the back of each tooth has thin protrusions.

This would have helped the pliosaur pierce flesh and then quickly extract its prey, ready for a quick second attack.

The pliosaur was a killing machine and, at 10 to 12 meters long and with four powerful fin-like limbs to propel itself at high speeds, it became a top ocean predator, experts say.

“The animal was so large that I think it would have been able to attack anything that was unfortunate enough to be in its space,” says Andre Rowe of the University of Bristol in England.

“I have no doubt it was like an underwater tyrannosaur.”

Its prey included other reptiles, such as its long-necked cousin, the plesiosaur, and the dolphin-like ichthyosaur.

Fossil evidence reveals that the pliosaur possibly even fed on other members of its own species.

The way this fossil skull was recovered is extraordinary.

It all started with a chance discovery during a walk along a beach near Kimmeridge Bay, on the famous Jurassic coast of southern England, considered a UNESCO World Heritage Site, the UN arm for education, science and culture.

Steve Etches’ friend and fellow fossil enthusiast, Phil Jacobs, found the tip of the pliosaur’s snout lying in the gravel. He was unable to carry it alone due to its weight, so he called Steve, and the pair assembled a makeshift stretcher to take the fossil to a safe location.

Removing fossils from rocks is always hard and delicate work. But doing so while hanging from ropes on a crumbling cliff, 50 feet above the beach, requires an unusual level of skill.

The courage, dedication and months spent cleaning the skull were certainly worth it.

Scientists from around the world will want to visit the Dorset fossil to gain new information about how these incredible reptiles lived and dominated their ecosystem.

According to her, one can infer from them the size of the muscles behind the pliosaur’s jaws and the forces generated when its mouth closed and crushed its prey.

At the upper limit, this amounts to about 33 thousand newtons.

To give you an idea, the most powerful jaws of living animals are found in saltwater crocodiles, with 16 thousand newtons.

“If you can generate a really powerful bite, you can incapacitate your prey; it’s less likely to escape. A powerful bite means this animal could crush tissue and bone quite effectively,” explains Rayfield.

“As for feeding, crocodiles close their jaws around something and then twist, to perhaps rip off a limb from their prey. This is a characteristic of animals that have heads that are expanded at the back, and we see this in the pliosaur.”

This newly discovered fossil has characteristics that indicate it had some particularly keen and very useful senses.

Its snout is full of small cavities in which there were probably glands to help it detect changes in water pressure made by possible prey.

And in its head there is a hole that would house a parietal eye, or third eye. Lizards, frogs and some live fish also have it. It is sensitive to light and may have helped locate other animals, especially when the pliosaur was emerging from deep, murky waters.

Steve Etches will display the skull next year at his museum in Kimmeridge — the Etches Collection.

You can see some vertebrae protruding from the back of the head, but disappearing after just a few bones. They are a tantalizing clue that more fossils may still lie in the cliff.

Etches says he’s eager to finish what he started.

“I’d bet my life that the rest of the animal is there,” he tells the BBC.

“We must extract it as soon as possible because it is in a very rapidly eroding environment. This part of the cliff line is receding meters per year. And it won’t be long before the rest of the pliosaur disappears and is lost. It’s a once-in-a-lifetime opportunity .”