Biggest Dinosaur In The Sea

Biggest Bird Mimic Dinosaur


FunkMonk/Wikimedia Commons

It took a long time for Deinocheirus, the “terrible hand,” to be correctly identified by paleontologists. The huge forelimbs of this feathered theropod were discovered in Mongolia in 1970, and it wasn’t until 2014 that Deinocheirus was conclusively pegged as an ornithomimid, or “bird mimic,” dinosaur. At least three or four times the size of North American ornithomimids like Gallimimus and Ornithomimus, the six-ton Deinocheirus was a confirmed vegetarian, wielding its massive, clawed front hands like a pair of Cretaceous scythes.

Giant Sea Lizards Ruled The Waves While T Rex Roamed On Land

A new fossil discovery shows marine reptiles called mosasaurs lived up until the asteroid impact that killed non-avian dinosaurs

Science Correspondent


There hardly was a more fearsome family of seagoing carnivores than the mosasaurs. From the time the first of these marine lizards slipped into the oceans about 98 million years ago, mosasaurs diversified into a widespread array of aquatic ambush predators that fed on everything from dinosaurs washed out to sea to other mosasaurs. And while it was once thought that these reptiles started to disappear from Earths oceans millions of years before a catastrophic asteroid strike closed the Cretaceous period, a fossil find in North Dakota is helping to rewrite the history of these voracious lizards.


The fate of the last mosasaurs was a cap on more than 30 million years of evolutionary history. Early mosasaurs were descended from a monitor lizard-like ancestor that adapted to a marine lifestyle, Van Vranken says, possibly during a time when sea levels were rising worldwide and new food sources were available for reptiles that didnt mind getting their feet wet. Fossils such as Dallasaurus and Russellosaurusboth found in the Cretaceous rocks of Texasoffer hints that these first mosasaurs looked like creatures caught in between a Komodo dragon and Mosasaurus.

How Did They Figure That Out

Lomax and Massare travelled to Alberta, Canada, to examine the much more complete fossil of Shonisaurus sikanniensis, a 69-foot-long ichthyosaur found in 2004. Comparing the new fossil to the same bone in the jaw of Shonisaurus revealed that the new bone is 25 percent bigger. Scaling up the animals full body gave the team their 85-foot size estimate.

Reconstructions of the giant ichthyosaur Shonisaurus show its skeletal structure and what it might have looked like in life.

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What Did Mosasaurs Eat And How Did They Catch It

Family: Mosasauridae


In another fossil find, a juvenile Mosasaurus was found in the stomach of another mosasaur species, Prognathodon kianda. The fossil, from the Smithsonian National Museum of Natural History , demonstrates that even the largest mosasaur species could be preyed upon. In fact, Mosasaurus hoffmanni fossils have been uncovered with severely broken and healed jaws that indicate they led a violent or dangerous lifestyle, according to a 1995 study published in the journal Philosophical Transactions of the Royal Society B.

Mosasaurus probably hunted in fairly deep waters, but would not have traveled too far from the shore, according to the NMNH.

Mosasaurs may have started out swimming through the water like a snake or an eel, but mosasaur tails changed over time. The animals evolved to have a shark-like tail to propel themselves through the water. They may also have been capable of a powerful breaststroke, using their paddle-like forelimbs to assist in sudden bursts of speed to catch prey.

Sea Animal: New Research Has Revealed That The Ichthyosaurus Species That Lived In The Dinosaur Era Was The Most Gigantic Sea Creature That Ever Lived On Earth

Giant Fossil Predator Provides Insight into the Rise of Modern Marine ...

Image: Unsplash/Representative Image

New research has revealed that the ichthyosaurus species that lived in the dinosaur era was the most gigantic sea creature that ever lived. The proceedings of the study were published in Science Magazine, which revealed that ichthyosaurs, a group of fish-shaped marine reptiles, evolved to gigantic sizes in a timeframe of only 2.5 million years. As per the research, whales took around 90% of their 55 million-year evolution to achieve such huge sizes, but it took ichthyosaurs only the first 1% of their 150 million-year evolution to achieve such massive sizes.

According to the introduction of the study, “We describe an ichthyosaur with a 2-m-long skull from the Fossil Hill Fauna as a new species of Cymbospondylus.” At present, this is the largest known tetrapod of its time, on land or in the sea, and is the first in a series of ocean giants. “

Researchers have observed that ichthyosaurs evolved to gigantic size in a much shorter time span than whales, during the time when the world was recovering from devastating extinction. According to Lars Schmitz, who is an associate professor of biology at Scripps College in Claremont, California, “ichthyosaurs evolved gigantism much faster than whales, in a time where the world was recovering from devastating extinction ,” reported Sputnik, citing LiveScience.

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Explain It To A Child

The Shonisaurus was the biggest water dinosaur that ever lived. It was really big, measuring up to 60 feet in length and weighing up to 20 tons. Most of its body was taken up by its long neck and tail, while its small head housed tiny eyes and a mouth full of sharp teeth.

This species is estimated to have been around 70 feet long and weighed around 45,000 pounds. They were likely apex predators of the ancient seas that lived around 250 million years ago.

Did Dinosaurs In The Ocean Survive

Trickle of food helped deep sea creatures survive asteroid strike that wiped out the dinosaurs. A team led by experts at Cardiff University has provided new evidence to explain why deep sea creatures were able to survive the catastrophic asteroid strike that wiped out the dinosaurs 65m years ago.

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How Big Was Mosasaurus And Other Mosasaurs

Mosasaurus species are among the largest members of the mosasaur family, according to the Philip J. Currie Dinosaur Museum. One of the biggest specimens ever found was identified as Mosasaurus hoffmanni and was estimated to be about 56 feet long in life, according to a 2014 study published in the journal Proceedings of the Zoological Institute RAS. Not all mosasaurs were giants though. Some species, such as Xenodens calminechari, were only about the size of a porpoise, Live Science previously reported.

The biggest Mosasaurus would have been comparable in size to the mighty megalodon a giant shark that dominated oceans in the middle Miocene and Pliocene epochs , long after the mosasaurs went extinct 65.5 million years ago. Megalodons could have reached up to 49 to 59 feet long, according to the Natural History Museum in London. Neither of these predators, however, were ever as big as the modern blue whale, which can reach up to 110 feet long and is the biggest known animal to have ever existed.

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What Is Its Environment And How It Lived

10 Biggest Sea Dinosaurs That Ever Existed on Earth

Shonisaurus Sikanniensis was an ichthyosaur that lived during the Late Triassic period.

It was well adapted to its environment, with large eyes that provided excellent vision underwater and a long tail that helped it swim quickly.

The majority of Shonisaurus Sikanniensis fossils have been found in British Columbia, Canada, suggesting that it preferred shallow, coastal waters. However, one fossilized individual was discovered in Nevada, USA, indicating that the species had a wide range.

It is possible that Shonisaurus migrated between different habitats in order to find food or mate.

Alternatively, the Nevada specimen could represent a rare case of a Shonisaurus individual becoming stranded in a different environment.

Regardless of its exact habitat, it is clear that Shonisaurus was a successful species that were well-adapted to life in the Triassic seas.

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What Happened To Mosasaurs

The mosasaurs disappeared from the fossil record alongside non-avian dinosaurs 65.5 million years ago, after a giant asteroid crashed into Earth at the end of the Cretaceous period. The rich marine ecosystems that mosasaurs inhabited and depended upon for food collapsed after the asteroid strike, according to a 2005 study in the Netherlands Journal of Geosciences. This collapse caused all mosasaurs to die out, never to return.

The role of dominant ocean predator was once held by marine reptiles that resembled modern dolphins, known as ichthyosaurs. Those animals were succeeded by the plesiosaurs, which were then replaced by the mosasaurs, according to the Naranjo Museum of Natural History. After mosasaurs disappeared, crocodilians increased in numbers and took over the role of large marine predators, according to the Netherlands Journal of Geosciences study.

How Big Was Tylosaurus

Tylosaurus was among the largest of all the mosasaurs, along with Hainosaurus and Mosasaurus, reaching maximum lengths of 49 feet and weighing around 7 tons. It had a sleek body and long, narrow, muscular jaws and a blunt, powerful head from which it takes its name, and which may have been used to ram and stun prey and used in intraspecific combat. It had agile flippers and a flexible fin on the end of its long tail.

Nobu Tamura, CC BY-SA 4.0, via Wikimedia Commons

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Are There Frozen Dinosaurs In Antarctica

Today the continent of Antarctica holds the evidence of that ancient world frozen beneath its ice and snow. As the climate changes again melting Antarctic ice is allowing scientists to discover the remains of the pastincluding the fossils of those distinctive dinosaurs like Cryolophosaurus and Glacialisaurus.

Fossils Of Giant Sea Lizard That Ruled The Oceans 66 Million Years Ago Discovered

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University of Bath
Fossils of a giant killer mosasaur have been discovered, along with the fossilized remains of its prey.

Researchers have discovered a huge new mosasaur from Morocco, named Thalassotitanatrox, which filled the apex predator niche. With massive jaws and teeth like those of killer whales, Thalassotitan hunted other marine reptiles — plesiosaurs, sea turtles, and other mosasaurs.

At the end of the Cretaceous period, 66 million years ago, sea monsters really existed. While dinosaurs flourished on land, the seas were ruled by the mosasaurs, giant marine reptiles.

Mosasaurs weren’t dinosaurs, but enormous marine lizards growing up to 12 metres in length. They were distant relatives of modern iguanas and monitor lizards.

Mosasaurs looked like a Komodo dragon with flippers instead of legs, and a shark-like tail fin. Mosasaurs became larger and more specialised in the last 25 million years of the Cretaceous, taking niches once filled by marine reptiles like plesiosaurs and ichthyosaurs. Some evolved to eat small prey like fish and squid. Others crushed ammonites and clams. The new mosasaur, named Thalassotitan atrox, evolved to prey on all the other marine reptiles.

Fossilised remains of prey

“It’s circumstantial evidence,” said Dr Nick Longrich, Senior Lecturer from the Milner Centre for Evolution at the University of Bath and lead author on the study, published in Cretaceous Research.

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Kids Facts And Information

Do you want to know which dinosaurs became swimming dinosaurs?

Or learn that most of the huge swimming monsters we know of were sea reptiles and not dinosaurs. These huge creatures lived in the sea the same time dinosaurs roamed the Earth.

Find out how big they were, what they ate – facts, pictures and information for kids.

Types Of Sea Reptiles

Nothosaurus by Nobu Tamura

The first large ocean reptiles were nothosaurs, which means ‘false reptile’. They lived in the Triassic period probably like seals of today live. There are about a dozen different species but the most well known of them is the Nothosaurus. It was about 4 metres , with long, webbed toes and it may have had a fin on its tail.

Plesiosaurs came next, living from early Jurassic until the end of the Cretacious period. Most of them had long necks and small heads – but ranged from about 2.5metres to 14 metres long.

Pliosaurus by Dmitry Bogdanov

The biggest of these was the Pliosaurus. It had teeth over 30 centimetres long and a bite four times more powerful than a Tyrannosaurus Rex. It is estimated to be 15 metres long.

Another plesiosaur is the long-necked Elasmosaurus.

Elasmosaurus from Wikipedia

It had four paddle shaped flippers and was about 14 metres long. They were very slow swimmers and would probably have followed schools of fish to eat.

Their necks were so long they wouldn’t have been able to lift them above the water unless they were in very shallow water with their body lying on the bottom.

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Dense Bones Allowed Spinosaurus The Biggest Carnivorous Dinosaur Ever Discovered To Hunt Underwater

Spinosaurus, the longest predatory dinosaur known, is opening its elongate jaws, studded with conical teeth, to catch a sawskate. Contrary to previous suggestions, this animal was not a heron-like wader it was a river monster, actively pursuing prey in a vast river system located in modern-day North Africa. Dense bones in the skeleton of Spinosaurus strongly suggest it spent a substantial amount of time submerged in the water. Credit: Davide Bonadonna

Its close cousin Baryonyx probably swam too, but Suchomimus mightve waded like a heron.

Baryonyx, from Surrey in England, swims through an ancient river with a fish in its jaws. Like its much larger African relative Spinosaurus, Baryonyx had dense bones, suggesting that it too spent much of its time submerged in water. It was previously thought to have been less aquatic than its Saharan relative. Credit: Davide Bonadonna

The fossil record is trickyamong spinosaurids, there are only a handful of partial skeletons, and we dont have any complete skeletons for these dinosaurs, says Matteo Fabbri, a postdoctoral researcher at the Field Museum and the lead author of the study in Nature. Other studies have focused on interpretation of anatomy, but clearly if there are such opposite interpretations regarding the same bones, this is already a clear signal that maybe those are not the best proxies for us to infer the ecology of extinct animals.

Largest Dinosaurs In The World

10 Biggest Sea Dinosaurs | Prehistoric Marine Reptiles

Many dinosaurs that once walked the Earth were so huge that its nearly impossible to wrap our heads around their sheer size. While plenty of dinosaurs have a reputation for being quite large, these 15 gigantic discoveries will give you a newfound appreciation for how intimidating they would have been to see firsthand. A great number of these ancient behemoths were members of the Sauropod group, lumbering calmly across the Earth in search of water and edible plants. Lets learn a little bit about 15 of the largest dinosaurs to ever walk the planet and see what sets each of them apart.

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Rutland Ichthyosaur Fossil Is Largest Found In Uk

The largest UK example of a predator that roamed the seas at the time of the dinosaurs has been uncovered.

The 33ft long ichthyosaur fossil, which is about 180 million years old, was found at Rutland Water Nature Reserve.

Similar in shape to dolphins, the reptiles – known as sea dragons – varied in size from 3 – 82ft .

Anglian Water, which owns the area, said it was now seeking funding to protect and display the remains nearby.

As well as being the biggest, it is also the most complete fossil of its kind found in the UK and is also thought to be the first ichthyosaur of its specific species found in the country.

When lifted for conservation and study, the block containing the 6ft skull and surrounding clay, alone weighed a tonne.

It was discovered by Joe Davis, conservation team leader at Leicestershire and Rutland Wildlife Trust, during the routine draining of a lagoon island for re-landscaping in February 2021.

Mr Davis said: “The find has been absolutely fascinating and a real career highlight.

“It’s great to learn so much from the discovery and to think this amazing creature was once swimming in seas above us.

“Now, once again, Rutland Water is a haven for wetland wildlife albeit on a smaller scale.”

Palaeontologist Dr Dean Lomax has studied thousands of ichthyosaurs and was head of the excavation team.

He said: “It was an honour to lead the excavation.

“Britain is the birthplace of ichthyosaurs – their fossils have been unearthed here for over 200 years.

The 20 Biggest Dinosaurs And Prehistoric Reptiles

  • B.S., Cornell University

Identifying the biggest, often deadly, dinosaurs that ever lived isn’t as easy a task as you might think: sure, these giant beasts left giant fossils, but it’s very rare to unearth a complete skeleton . On the following slides, you’ll find the biggest dinosaurs, according to the current state of researchas well as the biggest pterosaurs, crocodiles, snakes, and turtles.

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Water Dinosaurs In Jurassic World

If you watch Jurassic World, you can see some of these remarkable sea creatures make their appearances. The Mosasaurus species was seen chomping down a great white shark during the film, and pulling the massive T-Rex into the water at the end of the film.

Unfortunately, mosasaurs went extinct more than 65.5 million years ago during the same mass extinction that killed off the dinosaur population. But, according to the Philip J. Currie Dinosaur Museum, the Mosasaurus species is one of the most prominent members of this dinosaur family.

One of the largest ocean species ever found grew to 56 feet long during its life. However, not every mosasaur was that giant. Many of them were only the size of an average porpoise. Even with that said, many people refer to them as the T-Rex of the seas.

Uniquely enough, mosasaur fossils are often found with the content of their stomachs intact. Because of this incredible preservation, paleontologists are able to gather more information on their hunting strategies and diets.

Scientists also know that these creatures evolved to have shark-like tails, allowing them to propel themselves quickly through the water. The tail eventually progressed further, allowing them to use powerful breaststrokes with sudden bursts of speed.

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