Marine and aquatic dinosaurs
Ichthyosaur
Period: This species lived during the Jurassic period, between 200 and 190 million years ago.
Location: Based on fossil findings, it has been determined that the species inhabited various parts of the oceans worldwide.
Diet: Carnivore.
Length: 1.83 meters.
Weight: Between 81 and 92 kilograms.

The Ichthyosaur, whose name means fish lizard, was an aquatic reptile that inhabited the Earth’s oceans in the Jurassic, between 190 and 200 million years ago.
From the study of their fossils it has been determined that a specimen could grow up to 1.83 meters high, and weigh up to 92 kilograms. Due to its physical appearance, due to the existing similarities, it could be thought that the ichthyosaur was the ancestor of modern dolphins. The bones of his ears and eyes were large, which inclined to think that he had great acuity in both directions.
Likewise, its anatomy presumably allowed it to reach swimming speeds of up to 40 kilometers per hour and capture the species that made up its carnivorous diet, mainly fish.
The finding of some fossils with young inside inclines to think that the ichthyosaur did not lay eggs like other reptiles, but gave birth to its descendants.
Askeptosaurus
Period: Mid Triassic period, between 235 and 225 million years ago.
Location: Various parts of Europe, from the discovery of fossils.
Diet: Carnivore.
Length: 1.83 meters.
Weight: between 23 and 32 kilograms.

Askeptosaurus inhabited European waters during the Triassic period, approximately 220 million years ago. It was part of a family of diapsid reptiles, called Thalattosaurus.
The main fossil finds have occurred in European countries such as Italy and Switzerland, although this does not rule out that in addition to Europe they have entered other waters.
The Askeptosaurus was very similar in its habits and routines to the aquatic reptiles of today. They were mostly submerged in water and dabbled in land only to lay their eggs.
As for his physique, he was slender in build, with a long neck, body, and tail, suggesting that he might move in the water just as eels do, and that he could dive to great depths to catch fish and other species. members of their carnivorous diet.
Elasmosaurus
Period: End of the Cretaceous period (70 million years ago).
Location: Oceans around the world.
Diet: Carnivore.
Length: 13.72 meters.
Weight: From two thousand to three thousand kilograms.

This species, whose name means “tape lizard”, swam in oceans around the world during the Cretaceous period, approximately 70 million years ago.
It was part of the Elasmosauridae family, made up of very long-necked marine reptiles. Estimates show that Elasmosaurus specimens could reach a length of 13.72 meters and weigh between two and three thousand kilograms.
As distinctive features of the animal’s anatomy or constitution, the 71 cervical vertebrae of its neck, its slightly flat skull, its long conical teeth, its oar-shaped fins and its short tail can be pointed out; all useful attributes for swimming and fishing of minor species, members of their carnivorous diet.
Megalodon
Period: Between 28 and 2 million years ago, between the Oligocene and the Pleistocene
Fossil locations: In all oceans
Approximate length: Between 14 and 20 meters
Approximate weight: 50 tons
Diet: Carnivore

We find one of the shark species that lived the longest in the seas, something that was achieved thanks to its physical strength, its ability to adapt and, of course, a murderous instinct that made it one of the most lethal prehistoric predators that they were in the sea. It inhabited the seas and oceans in the Conozoic Era, around 2.6 million years ago, having its name with a meaning that completely defined it. The megalodon means “big tooth” since its teeth could measure around 20 centimeters and were made to devour and destroy its victims. It has been found that it has a structure of teeth very similar to that of the white shark and during its life it detaches from its teeth, reborn new ones with more force. If we compare the bite of the Megalodon with that of the Tyrannosaurus Rex, we can verify that that of this marine animal is up to 5 times stronger than that of the reptile, being able to feed on practically any animal. Its extinction is related to the lack of prehistoric whales, which confirmed its main source of food, and since these did not exist, the megalodons were extinguishing.
Liopleurodon
Period: 162 to 144 million years ago, in the Jurassic
Fossil locations: France
Approximate length: 30 meters
Approximate weight: 75-150 Tons
Diet: Carnivore

If you want to find one of the largest carnivorous animals on Earth, you would have to look back about 165 million years to find the Liopleurodon which was capable of measuring more than 30 meters and weighing up to 150 tons. It is an aquatic dinosaur that rivaled other animals, and it was the terror of the seas since, in addition to having a large mouth with sharp teeth, it was able to move nimbly underwater, turning and propelling itself towards its prey, something that gave them little choice in life. This size and ease of hunting ensured that even the fiercest predators were included as a diet in their daily diet. It is an animal that had to eat constantly, so when it began to run short of prey of the size necessary for its survival, it began to become extinct.
Kronosaurus
Period: Between 125 and 97 million years ago, in the lower and upper Cretaceous
Fossil locations: Australia and South America
Approximate length: 10.5 meters
Approximate weight: 12 tons
Diet: Carnivore

The name of this great lizard came from the god Kronos and during the Middle Cretaceous (that is to say 110 million years ago) it was found in the seas of Earth. It is said that it may be a very distant relative of the crocodiles since they are very similar both in the length of their bodies and in their jaws. The length of its body was about 10 meters, although much higher specimens have been found. His head was very strong and powerful, something that was appreciated in his jaws that he used to catch and break the bones of his prey. As a curious fact, these reptiles have been found fossilized with many stones in their stomach, which suggests that the Kronosaurus ingested stones or to grind the food they had just taken and in this way make their digestion easier, or to help them to dive, acting as a counterweight. These animals, despite being almost all their lives in the sea, went to dry land to lay their eggs, something that current sea turtles also do.
Livyatan
Period: Miocene, 15 million years ago.
Fossil locations: Peru
Approximate length: 17.5 meters
Approximate weight: 30 tons
Diet: Carnivore

We find a species that has been discovered very recently and that dates back to at least 15 million years ago. The Livyatan is closely related to the whales, at least in similarity and they lived what in their time would be South America. It was an animal that reached 20 meters in length and was very fierce and aggressive. His teeth are one of the largest on record, at about 36 centimetres long, he was able to tear apart any meat. Its head or nose is very flat, reaching the same level as the mouth, with hard and resistant bones, which suggests that it used this part of its body so much to hit its prey, leaving them wounded and then devouring them or even when fighting with other males of its species to get to mate. In the case of having to face a large prey, all went together towards it, causing great damage, so those that did not die on the spot, did so later.
Dunkleosteus
Period: Between 368 and 359 million years ago, in the Upper Devonian
Fossil locations: North America, Europe and Africa
Approximate length: 10 meters
Approximate weight: 6 tons
Diet: Carnivore

The Dunkleosteus was one of the armored fish that lived more than 350 million years ago and had a body covered with large bone plates that it used to defend itself against other predators, although they are also known as animals that practiced cannibalism, with an aspect very close to the piranhas that today inhabit our waters. Its fins were short and very close to the body, with the exception of the tail, being able to measure this more than a meter, using it to move at high speed with each movement. One of the most characteristic features of these animals is that they did not have teeth as we can identify them, but that it was a hard and very sharp bone that did this and covered the entire jaw. They were very aggressive animals, although they used to be in groups, when one bothered another they could end up fighting or devoured by themselves.
Pliosaurus
Period: Between 155.7 and 147 million years ago, in the Upper Jurassic
Fossil locations: Everyone
Approximate length: Between 10 and 15 meters
Approximate weight: Between 8 and 12 tons
Diet: Carnivore

This has been one of the marine dinosaurs that has taken the longest to discover, having several names before choosing Pliosaurus. When their fossils were found in an arctic region, it was not known which animal they were facing, so it was called Predator X. It is a marine reptile that inhabited in the Jurassic era and that thanks to its ferocity could feeding on countless animals, even those that could be larger, since their movements were fast and their body, being relatively slimmer, could also maneuver better to escape the attacks of their prey. Its head was long and could feed on other reptiles and fish. Its bite strength has been found to be much greater than that of the T-Rex, which is why few dinosaurs came out alive after being bitten by this sea beast.
Eurypterida
Period: About 400 million years ago, in the Lower Devonian
Fossil locations: Germany
Approximate length: 3 meters
Approximate weight: 180 kilos
Diet: Carnivore

Although its scientific and technical name is Eurypterida, it is commonly known by the sea scorpion. It is called this way because it had a sting that it used to hunt and paralyze its prey, and could then feed on them. Its approximate size is about 3 meters, being able to feed on various fish and animals with ease. Although what is known about these prehistoric marine animals is that they lived in the oceans, it is known that they ended up climbing through the mouths of rivers, they reached marshes and other lakes where their size was decreasing over the years.
Also read: 10 Scary Prehistoric Animals – That Weren’t Dinosaurs