Sea lizard. Giant reptiles of the Mesozoic seas. What does a marine iguana look like?
Some of the largest creatures that have ever inhabited this world lived millions of years ago. Below are ten of the biggest, most feared sea monsters that once roamed the oceans:
10 Shastasaurus
Ichthyosaurs were marine predators that looked like modern dolphins and could grow to enormous sizes and lived during the Triassic period about 200 million years ago.
Shastasaurus, the largest marine reptile ever found, was an ichthyosaur that could grow to over 20 meters. It was much longer than most other predators. But one of the largest creatures ever to swim in the sea wasn't exactly a fearsome predator; Shastasaurus fed by suction, and ate mainly fish.
9. Dacosaurus (Dakosaurus)
Dacosaurus was first discovered in Germany, and with its strangely reptilian yet fish-like body, it was one of the main predators in the sea during the Jurassic.
Its fossils have been found over a very wide area - they have been found everywhere, from England to Russia to Argentina. Although it is usually compared to modern crocodiles, Dacosaurus could reach 5 meters in length. Its unique teeth have led scientists to believe that it was the top predator during its terrible reign.
8. Thalassomedon (Thalassomedon)
Thalassomedon belonged to the Pliosaur group, and its name is translated from Greek as "Sea Lord" - and for good reason. Thalassomedons were huge predators, reaching up to 12 meters in length.
He had almost 2 meter fins, which allowed him to swim in the depths with deadly efficiency. Its reign as a predator continued until the Late Cretaceous, until it finally came to an end when new larger predators such as Mosasaurus appeared in the sea.
7. Nothosaurus (Nothosaurus)
Nothosaurs, reaching a length of only 4 meters, were aggressive predators. They were armed with a mouthful of sharp, outwardly pointing teeth, indicating that their diet consisted of squid and fish. It is believed that Nothosaurs were primarily ambush predators. They used their sleek, reptilian physique to sneak up on their prey and surprise them when they attacked.
It is believed that Nothosaurs were related to Pliosaurs, another type of deep sea predator. Fossil evidence suggests that they lived during the Triassic period about 200 million years ago.
6. Tylosaurus (Tylosaurus)
Tylosaurus belonged to the Mosasaurus species. It was enormous in size, reaching over 15 meters in length.
Tylosaurus was a meat eater with a very varied diet. Traces of fish, sharks, smaller mosasaurs, plesiosaurs, and even some flightless birds have been found in their stomachs. They lived at the end of the Cretaceous in the sea that covered what is now North America, where they were densely located at the top of the marine food chain for several million years.
5. Talattoarchon (Thalattoarchon Saurophagis)
Only recently discovered, Talattoarchon was the size of a school bus, reaching almost 9 meters in length. It is an early species of ichthyosaur that lived during the Triassic period, 244 million years ago. Because they appeared shortly after the Permian Extinction (the largest mass extinction on Earth when scientists believe 95% of marine life was wiped out), his discovery gives scientists a new way to look at the rapid recovery of the ecosystem.
4. Tanystropheus
Although Tanystropheus was not strictly a marine inhabitant, his diet consisted mainly of fish, and scientists believe that he spent most of his time in the water. Tanystropheus was a reptile that could reach 6 meters in length and is believed to have lived during the Triassic period about 215 million years ago.
3. Liopleurodon (Liopleurodon)
Liopleurodon was a marine reptile and reached over 6 meters in length. It mainly lived in the seas that covered Europe during the Jurassic period and was one of the best predators of its time. Some of his jaws are believed to have reached more than 3 meters - this is approximately equal to the distance from floor to ceiling.
With such huge teeth, it is not difficult to understand why Liopleurodon dominated the food chain.
2. Mosasaurus (Mosasaurus)
If Liopleurodon was huge, then Mosasaurus was colossal.
Fossil evidence suggests that Mosasaurus could reach up to 15 meters in length, making it one of the largest marine predators of the Cretaceous period. The head of the Mosasaurus was similar to that of a crocodile, armed with hundreds of razor-sharp teeth that could kill even the most well-armored foes.
1. Megalodon (Megalodon)
One of the largest predators in marine history and one of the largest sharks ever recorded, Megalodons were incredibly fearsome creatures.
Megalodons roamed the depths of the oceans during the Cenozoic era, 28 to 1.5 million years ago, and were a much larger version of the great white shark, the most feared and powerful predator in the oceans today. But while the maximum length modern great white sharks can reach is 6 meters, Megalodons could grow up to 20 meters in length, which means they were bigger than a school bus!
Elasmosaurs are ancient lizards of the plesiosaur order. They reigned on the planet in the Triassic period, and in the Cretaceous period they were gone.
The average body length of Elasmosaurus was about 15 meters. The spine was formed from a large number of flat vertebrae, which could be up to 150 pieces.
The evolutionary process changed the limbs of elasmosaurs and turned them into large flippers.
These dinosaurs once lived in the sea, which was previously located on the site of modern Kansas.
Elasmosaurs were the most unusual creatures of the suborder. They had a very long and flexible neck, ending in a small head. At the same time, the Elasmosaurus had a wide mouth, and the teeth were shaped like spikes.
By the number of cervical vertebrae, these dinosaurs are certainly in first place among the rest. For example, we can compare the cervical region of a giraffe, which consists of only 7 vertebrae.
These lizards could catch the fastest fish, the long neck helped to grab agile prey.
At times, these dinosaurs went to shallow water, lay down on the bottom and swallowed small pebbles, which helped to crush food and acted as ballast. About 250 stones were found in the stomach of one lizard. After studying the stones, scientists realized that elasmosaurs traveled several thousand kilometers throughout their lives, and collected stones in different parts of the coast. Most likely, the offspring of elasmosaurs, like other ichthyosaurs, were born in the sea.
For the first time, the remains of this creature were found in 1868 by E. Kop. Elasmosaur bones have been found in the United States, Japan, and Russia. These dinosaurs got their name from the flat bones of the pelvic and shoulder girdle.
It seemed that these toothy and big-eyed marine predators died out tens of millions of years ago, but there are reports that ichthyosaurs are still found in the seas and oceans. Although these ancient creatures are in many ways similar to dolphins, it is difficult to confuse them with them, because a distinctive feature of ichthyosaurs is their huge eyes.
Dolphin-like eyed lizards
Of the marine predatory dinosaurs, we are most familiar with plesiosaurs, and this is not surprising, because the famous Nessie is attributed to this type of aquatic lizards. However, other types of predatory reptiles once existed in the depths of the sea, for example, ichthyosaurs, which inhabited the seas and oceans 175-70 million years ago. Ichthyosaurs, which look like dolphins, according to scientists, were once among the first dinosaurs to return to the water element.
Unlike the plesiosaurus with its long neck, the head of the ichthyosaur, like that of fish, was integral with the body, and it is not for nothing that the name of this reptile is translated as “fish lizard”. In the bulk, ichthyosaurs did not differ in large sizes, their length was 3-5 meters. However, giants were also among them, for example, in the Jurassic period, some species reached a length of 16 meters, and in the polar regions of Canada, paleontologists discovered the remains of an ichthyosaur about 23 meters long (!), Which lived in the late Triassic.
These were toothy creatures, and their teeth were repeatedly replaced during their lives. It is especially worth stopping at the eyes of ichthyosaurs. These reptiles had very large eyes, reaching 20 cm in diameter in some species. According to scientists, this eye size suggests that ichthyosaurs hunted at night. The eyes were protected by a bone ring.
On the skin of these lizards there were no scales or horny plates, according to scientists, it was covered with mucus, which ensured better gliding in the water. Although ichthyosaurs are very similar to dolphins, they had a fish-like spine that curved in a horizontal plane, so their tail, like ordinary fish, was located in a vertical plane.
What did ichthyosaurs eat? It was widely believed that they had a preference for the extinct cephalopod belemnites, but a team of researchers led by Ben Kier from the South Australian Museum has refuted this notion. Scientists carefully examined the contents of the stomach of a fossilized ichthyosaur that lived 110 million years ago. It turned out that it contained fish, small turtles and even a small bird. This study allowed us to refute the hypothesis that ichthyosaurs became extinct due to the disappearance of belemnites.
It is curious that these marine reptiles were viviparous, this feature of them is clearly proven by paleontological finds. Scientists have repeatedly found the fossilized remains of ichthyosaurs, in the belly of which there were skeletons of unborn cubs. Newborn ichthyosaurs were forced to immediately begin an independent life. According to scientists, only when they were born, they already knew how to swim perfectly and get their own food.
Mysterious "weevil whales"
Ichthyosaurs reached their greatest diversity during the Jurassic period, and died out at the end of the Cretaceous. Maybe they didn't die? After all, there is an opinion of a number of scientists that the same ichthyosaurs were warm-blooded and could well adapt to the changed conditions in the ocean. When these lizards that have survived to this day die or die, their remains sink to the bottom, scientists do not find them, respectively, and consider ichthyosaurs extinct.
In the early 1980s, the sailor of the Soviet cargo ship A. B. Fedorov, while sailing in the Indian Ocean, observed unusual marine animals, according to his description, very similar to ichthyosaurs. An eyewitness recalled: “I saw a light brown back and a characteristic whale fountain, but ... it was not a whale or a dolphin. This is the first and so far the only time I have seen such an animal in my life. The fact that this is some kind of mutant is out of the question. There were at least five of these long-nosed, toothy "whales" with large saucers-eyes. More precisely, the eyes were in the center of the saucers.
If this observation were the only one, it could be assumed that the sailor was mistaken and mistook quite ordinary inhabitants of the ocean for unusual creatures. However, in the spring of 1978, two members of the crew of the fishing vessel V.F. Varivoda and V.I. Titov observed a very strange sea animal with a toothy mouth. Titov described it this way: “A steep, rounded nape rose about 1.5 meters above the water, a white stripe stood out clearly on the upper jaw, which, gradually expanding, stretched from the end of the muzzle to the corner of the mouth and was bordered from below by a narrow black stripe ... In the profile of the head was cone-shaped. The height of the upper jaw at the level of the corner of the mouth was about one meter ... The total length of the head was from one and a half to two meters.
V. I. Titov told A. Kuzmin, a senior researcher at the laboratory of cetaceans, Candidate of Biological Sciences, about the mysterious animal he had encountered. The scientist had known Titov by that time for 10 years, so he took his story seriously. It is curious that Titov told him that he had seen similar "weevil whales" in the Indian Ocean more than once, and such animals usually kept in a small flock of 6-7 individuals, sometimes there were cubs among them.
Kuzmin showed his friend a lot of photographs and drawings of various marine animals, but Titov did not recognize his "weevil". But, when an image of an ichthyosaur accidentally caught his eye, he said that he was very similar to the creatures he met.
A very living fossil?
So, there are observations of people who are trustworthy who have seen unknown large marine animals, very similar to ichthyosaurs that died out tens of millions of years ago. Why not assume that ichthyosaurs, which at one time were distributed almost everywhere in all seas and oceans, managed to survive to our time, only significantly reducing their habitat?
It should be noted that even Soviet scientists took the messages of Fedorov and Titov quite seriously, information about a meeting with a large marine animal unknown to science was published in 1979 in the journal Knowledge is Power. The skepticism of scientists in recent times, of course, has been strongly influenced by the discovery of the lobe-finned fish, which was considered extinct long ago. If she managed to survive to this day, then why couldn't the ichthyosaur do it?
French scientists came to the conclusion that ichthyosaurs were warm-blooded. This conclusion was made on the basis of data on the content of the stable oxygen isotope 18 0 in the fossil remains of ichthyosaurs. It was possible to prove that the body temperature of marine reptiles was higher than the body temperature of fish that lived with them at the same time. This discovery of scientists speaks in favor of the fact that ichthyosaurs could well survive, especially since they did not eat only belemnites. It remains to be seen when more solid evidence of the existence of these prehistoric animals appears. Fortunately, now many sailors have both cameras and video cameras, and we may well hope to see footage in which a whole flock of big-eyed and toothy creatures from the Jurassic period will frolic in the waves.
Prepared by Andrey SIDORENKO
marine reptiles
When studying life in the Mesozoic, perhaps the most striking thing is that almost half of all known reptile species lived not on land, but in water, in rivers, estuaries, and even in the sea. We have already noted that in the Mesozoic, shallow seas were widespread on the continents, so there was no shortage of living space for aquatic animals.
In the Mesozoic layers, there are a large number of fossil reptiles adapted to life in the water. This fact can only mean that some reptiles returned back to the sea, to their homeland, where once upon a time the ancestors of dinosaurs appeared - fish. This fact requires some explanation, since at first glance there was a regression here. But we cannot consider the return of reptiles to the sea as a step back from an evolutionary point of view only on the grounds that the Devonian fishes emerged from the sea onto land and developed into reptiles, passing through the amphibian stage. On the contrary, this proposition illustrates the principle that each actively developing group of organisms tends to occupy all the varieties of environment in which it can exist. In fact, the movement of reptiles into the sea is not too different from the colonization of rivers and lakes by amphibians in the Late Carboniferous (photo 38). There was food in the water and the competition was not too fierce, so first amphibians and then reptiles moved into the water. Already before the end of the Paleozoic, some reptiles became aquatic inhabitants and began to adapt to a new way of life. This adaptation went mainly along the path of improving the way of movement in the aquatic environment. Of course, the reptiles continued to breathe air in the same way as the modern whale breathes air, a mammal, although similar in body shape to a fish. Moreover, the Mesozoic marine reptiles did not evolve from any one land reptile that made the decision to go back into the water. Fossil skeletons provide undeniable evidence that they had different ancestors and appeared at different times. Thus, fossil remains show how varied the response of organisms to changing environmental conditions was, as a result of which a vast expanse abounding in food and suitable for settlement was created.
Extensive information has been obtained from the study of fossils contained in marine mudstones and Cretaceous limestones; in these fine clastic rocks, not only bones are preserved, but also imprints of skin and scales. With the exception of the smallest and most primitive species, most marine reptiles were carnivores and belonged to three main groups: ichthyosaurs, plesiosaurs, and mosasaurs. Briefly characterizing them, we must first of all note that ichthyosaurs acquired an elongated shape similar to fish (Fig. 50) and were excellently adapted for fast swimming in pursuit of fish or cephalopods. These animals, reaching 9 meters in length, had bare skin, a dorsal fin and tail like a fish, and their four limbs turned into a kind of seal flippers and were used to control the movement of the body when swimming. All fingers in these flippers were closely connected, and additional bones existed in them to increase strength. The large eyes of ichthyosaurs were adapted to see well in the water. They even had one very significant improvement in the process of reproduction. Being animals that breathed air but lived in sea water, they could not lay eggs. Therefore, ichthyosaurs developed a method of reproduction in which the embryo developed inside the mother's body and, reaching maturity, was born alive. They became viviparous. This fact is established by the finds of excellently preserved remains of female ichthyosaurs with fully formed cubs inside their bodies, the number of cubs reaches seven.
Rice. 50. Four groups of animals that acquired a streamlined body shape as a result of adaptation to life in water: A. reptile, B. fish, C. bird, D. mammal. Initially, they had a different appearance, but in the course of evolution they acquired an external resemblance.
The second group includes plesiosaurs, which, unlike fish-like ichthyosaurs, retained the original shape of the reptile body, reaching 7.5-12 meters in length. If not for the tail, the plesiosaur would have looked like a giant swan. Of course, the ancestor of the plesiosaur was not at all the terrestrial reptile that gave rise to the ichthyosaurs. The legs of the plesiosaurs turned into long fins, and the head, planted on a long neck, was equipped with sharp teeth that closed and securely held the most slippery fish. Such teeth excluded chewing; The plesiosaurus swallowed the prey whole and then crushed it in the stomach with the help of pebbles. The diet of plesiosaurs can be judged from the stomach contents of one of them, which, apparently, died before the stones in his stomach had time to grind the food he swallowed to the right extent. The bones and fragments of shells contained in the stomach were found to belong to fish, flying reptiles and cephalopods, which were swallowed whole, along with the shell.
A third group of marine reptiles are called mosasaurs because they were first discovered near the Moselle River in northeastern France. They could be called "late" because they appeared in the late Cretaceous time, when ichthyosaurs had inhabited the seas for almost 150 million years. The ancestors of mosasaurs were lizards rather than dinosaurs. Their length reached 9 meters, they had scaly skin, and their jaws were arranged in such a way that they could open their mouths wide, like snakes.
A streamlined body as an adaptation to the conditions of life in the aquatic environment is found not only in ichthyosaurs and mosasaurs. The same can be seen in a number of animals that lived both before and after the Mesozoic, and in the Mesozoic (Fig. 50).
Dinosaurs were the dominant vertebrates that inhabited all the ecosystems of planet Earth for over 160 million years - from the Triassic period (about 230 million years ago) to the end of the Cretaceous period (about 65 million years ago). I want to acquaint you with a list of the ten most ferocious marine dinosaurs.
10 Shastasaurus
Shastasaurus (Shastasaurus) - a genus of dinosaurs that lived at the end of the Triassic period (more than 200 million years ago) in the territory of modern North America and, possibly, China. His remains have been found in California, British Columbia and the Chinese province of Guizhou. This predator is the largest marine reptile ever found on the planet. It could grow up to 21 meters in length and weigh 20 tons.
9 Dacosaurus
In ninth place in the ranking is Dakosaurus (Dakosaurus) - a marine crocodile that lived in the late Jurassic - early Cretaceous period (more than 100.5 million years ago). It was a rather large, carnivorous animal adapted almost exclusively to hunting large prey. Can grow up to 6 meters in length.
8. Thalassomedon
Thalassomedon is a genus of dinosaurs that lived in North America about 95 million years ago. Most likely, it was the main predator of its time. Thalassomedon grew up to 12.3 m in length. The size of its flippers reached about 1.5–2 meters. The length of the skull was 47 centimeters, teeth - 5 cm. He ate fish.
7. Nothosaurus
Nothosaurus (Nothosaurus) is a marine lizard that lived 240-210 million years ago in the territory of modern Russia, Israel, China and North Africa. In length reached about 4 meters. It had webbed limbs, with five long fingers that could be used both for movement on land and for swimming. Probably ate fish. A complete Nothosaurus skeleton can be seen at the Natural History Museum in Berlin.
6. Tylosaurus
In sixth place in the list of the most ferocious marine dinosaurs is Tylosaurus (Tylosaurus) - a large marine predatory lizard that inhabited the oceans at the end of the Cretaceous period (about 88-78 million years ago). It was the dominant marine predator of its time. It grew up to 14 m in length. It fed on fish, large predatory sharks, small mosasaurs, plesiosaurs, and waterfowl.
5. Talattoarchon
Talattoarchon (Thalattoarchon) - a large marine reptile that lived more than 245 million years ago in what is now the western part of the United States. The remains, consisting of part of the skull, spine, pelvic bones, and part of the hind fins, were discovered in Nevada in 2010. According to estimates, talattoarchon was the top predator of his time. It grew to at least 8.6 m in length.
4. Tanystropheus
Tanystropheus is a genus of lizard-like reptiles that lived in the Middle Triassic about 230 million years ago. It grew up to 6 meters in length, and was distinguished by a very elongated and mobile neck, which reached 3.5 m. It led a predatory aquatic or semi-aquatic lifestyle, probably hunting fish and cephalopods near the coast.
3. Liopleurodon
Liopleurodon (Liopleurodon) - a genus of large carnivorous marine reptiles that lived at the turn of the middle and late Jurassic period (from about 165 million to 155 million years ago). It is assumed that the largest known Liopleurodon was just over 10 m in length, but typical sizes for it range from 5 to 7 m (according to other sources, 16-20 meters). Body weight is estimated at 1-1.7 tons. These apex predators probably ambushed large cephalopods, ichthyosaurs, plesiosaurs, sharks, and other large animals they could catch.
2 Mosasaurus
Mosasaurus (Mosasaurus) is a genus of extinct reptiles that lived on the territory of modern Western Europe and North America during the Late Cretaceous - 70–65 million years ago. For the first time their remains were found in 1764 near the river Meuse. The total length of representatives of this genus ranged from 10 to 17.5 m. In appearance, they resembled a mixture of a fish (or a whale) with a crocodile. All the time they were in the water, plunging to a considerable depth. They ate fish, cephalopods, turtles and ammonites. According to some scientists, these predators are distant relatives of modern monitor lizards and iguanas.
1. Megalodon
Megalodon (Carcharocles megalodon) is an extinct species of prehistoric shark that lived throughout the oceans 28.1–3 million years ago. It is the largest known predatory fish in history. It is estimated that the megalodon reached 18 meters in length and weighed 60 tons. In body shape and behavior, it was similar to the modern white shark. He hunted cetaceans and other large marine animals. Interestingly, some cryptozoologists claim that this animal could have survived to the present, but apart from the found huge teeth (up to 15 cm in length), there is no other evidence that the shark still lives somewhere in the ocean.
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