Underwater lizards. Elasmosaurs - ancient sea lizards
The modern ocean is home to many incredible creatures, many of which we have no idea about. You never know what lies there - in the dark, cold depths. However, none of them compares with the ancient monsters that dominated the world's oceans millions of years ago.
In this article we will tell you about the lizards, carnivorous fish and predatory whales that terrorized sea creatures in prehistoric times.
Prehistoric world
Megalodon
Megalodon may be the most famous creature on this list, but it's hard to imagine that the school-bus-sized shark ever actually existed. Nowadays, there are many different scientific films and programs about these amazing monsters.
Contrary to popular belief, megalodons did not live at the same time as dinosaurs. They dominated the seas from 25 to 1.5 million years ago, which means they missed the last dinosaur by 40 million years. In addition, this means that the first people found these sea monsters alive.
Megalodon's home was the warm ocean, which existed until the last ice age in the early Pleistocene, and it is believed that it was he who deprived these huge sharks of food and the ability to reproduce. Perhaps in this way nature protected modern humanity from terrible predators.
Liopleurodon
If there was a water scene in the Jurassic Park movie that included some of the sea monsters of the time, Liopleurodon would definitely appear in it. Although scientists argue about the actual length of this animal (some say it was up to 15 meters), most agree that it was about 6 meters, with a fifth of the length being the pointed head of Liopleurodon.
Many people think that 6 meters is not so much, but the smallest representative of these monsters is capable of swallowing an adult. Scientists have recreated a model of Liopleurodon's fins and tested them.
During the research, they found that these prehistoric animals were not so fast, but they were not lacking in agility. They were also capable of making short, quick and sharp attacks, similar topics, which are performed by modern crocodiles, which makes them even more terrifying.
Sea monsters
Basilosaurus
Despite the name and appearance, they are not reptiles, as it might seem at first glance. In fact, these are real whales (and not the most frightening ones in this world!). Basilosaurs were the predatory ancestors of modern whales and measured between 15 and 25 meters in length. It is described as a whale, somewhat resembling a snake due to its length and ability to wriggle.
It's hard to imagine that while swimming in the ocean one could stumble upon huge creature, similar to a snake, whale and crocodile at the same time, 20 meters long. The fear of the ocean would stick with you for a long time.
Physical evidence suggests that basilosaurs did not have the same cognitive abilities as modern whales. In addition, they did not have echolocation capabilities and could only move in two dimensions (this means that they could not actively dive or dive to great depths). Thus, this terrible predator was as stupid as a bag of prehistoric tools and would not be able to pursue you if you dived or came onto land.
Cancerscorpios
Not surprisingly, the words "sea scorpion" only evoke negative emotions, however, this representative of the list was the creepiest of them. Jaekelopterus rhenaniae is special kind crayfish, which was the largest and most terrifying arthropod of that time: 2.5 meters of pure clawed horror under the shell.
Many of us are terrified of small ants or large spiders, but imagine the full spectrum of fear experienced by a person who would be unlucky enough to encounter this sea monster.
On the other hand, these creepy creatures went extinct even before the event that killed all the dinosaurs and 90% of life on Earth. Only a few species of crabs survived, which are not so scary. There is no evidence that the ancients sea scorpions were poisonous, but based on the structure of their tail, we can conclude that perhaps this really was the case.
Read also: A huge sea monster washed up on the coast of Indonesia
Prehistoric animals
Mauisaurus
Mauisaurus was named after ancient god The Maori Maui, who, according to legend, used a hook to pull out the skeletons of New Zealand from the bottom of the ocean, so just from the name you can understand that this animal was huge. The Mauisaurus's neck was about 15 meters long, which is quite a lot compared to its total length of 20 meters.
His incredible neck had many vertebrae, which gave it special flexibility. Imagine a turtle without a shell with a surprisingly long neck - that’s what this creepy creature looked like.
He lived during Cretaceous period, which meant that the unfortunate creatures jumping into the water to escape the velociraptors and tyrannosaurs were forced to come face to face with these sea monsters. Mauisaurs' habitats were limited to the waters of New Zealand, indicating that all inhabitants were in danger.
Dunkleosteus
Dunkleosteus was a ten-meter predatory monster. Huge sharks lived much longer than Dunkleosteus, but this did not mean that they were the best predators. Instead of teeth, dunkleosteus had bony growths, like some species of modern turtles. Scientists have calculated that their bite force was 1,500 kilograms per square centimeter, which put them on par with crocodiles and tyrannosaurs and made them one of the creatures with the strongest bite.
Based on facts about their jaw muscles, scientists concluded that Dunkleosteus could open its mouth in one fiftieth of a second, swallowing everything in its path. As the fish grew older, the single bony dental plate was replaced by a segmented one, which made it easier to obtain food and bite through the thick shells of other fish. In the arms race called the prehistoric ocean, Dunkleosteus was a real well-armored, heavy tank.
Sea monsters and monsters of the deep
Kronosaurus
Kronosaurus is another short-necked lizard, similar in appearance to Liopleurosaurus. What is noteworthy is that its true length is also known only approximately. It is believed that it reached up to 10 meters, and its teeth reached up to 30 cm in length. That is why it was named after Kronos, the king of the ancient Greek titans.
Now guess where this monster lived. If your assumption was related to Australia, then you are absolutely right. Kronosaurus's head was about 3 meters long and it was capable of swallowing an entire adult human. In addition, after this there was room inside the animal for another half.
Also, due to the fact that the flippers of kronosaurs were similar in structure to the flippers of turtles, scientists concluded that they were very distantly related and assumed that kronosaurs also went to land to lay eggs. In any case, we can be sure that the nests of these sea monsters as if no one dared to destroy.
Helicoprion
This shark, 4.5 meters long, had a lower jaw that was a kind of curl, studded with teeth. She looked like a hybrid of a shark and a buzz saw, and we all know that when dangerous power tools become part of a predator at the top of the food chain, the whole world trembles.
Helicoprion's teeth were serrated, which clearly indicates the carnivory of this sea monster, however, scientists still do not know for certain whether the jaw was pushed forward as in the photo, or moved slightly deeper into the mouth.
These creatures survived the Triassic mass extinction, which could indicate their high intelligence, but the reason could also be their living in the deep sea.
Prehistoric sea monsters
Melville's Leviathan
Earlier in this article we already talked about predatory whales. Melville's Leviathan is the most terrifying of them all. Imagine a huge hybrid of an orca and a sperm whale. This monster was not just a carnivore - it killed and ate other whales. It had the largest teeth of any animal known to us.
Their length sometimes reached 37 centimeters! They lived in the same oceans at the same time and ate the same food as megalodons, thus competing with the largest predatory shark of the time.
Their huge heads were equipped with the same echo-sounding devices as modern whales, which made them more successful in hunting muddy water. In case it wasn't clear to anyone from the start, this animal was named after Leviathan, the giant sea monster from the Bible and Herman Melville, who wrote the famous Moby Dick. If Moby Dick had been one of the Leviathans, he would certainly have eaten the Pequod and its entire crew.
It seemed that these toothy and big-eyed marine predators went extinct 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 similar in many ways to dolphins, it is difficult to confuse them with them, because distinctive feature Ichthyosaurs have huge eyes.
Dolphin-like lizards-eyed
From the sea predatory dinosaurs We are most familiar with plesiosaurs, and this is not surprising, because the famous Nessie is classified precisely as this type of aquatic lizard. However, other species also existed in the depths of the sea at one time. predatory reptiles, for example, ichthyosaurs that 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 plesiosaur with its long neck, the head of the ichthyosaur, like that of fish, was integral with the body; it is not for nothing that the name of this reptile is translated as “fish lizard”. For the most part, ichthyosaurs did not differ large sizes, their length was 3-5 meters. However, among them there were also giants, 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 replaced several times 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.
The skin of these lizards had neither scales nor horny plates; according to scientists, it was covered with mucus, which provided better gliding in the water. Although ichthyosaurs are very similar to dolphins, they had a fish-type 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 favored the extinct cephalopod belemnites, but a team of researchers led by Ben Kier from the South Australian Museum refuted this idea. Scientists have carefully examined the stomach contents of a fossilized ichthyosaur that lived 110 million years ago. It turned out that there were fish, small turtles and even a small bird in it. 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 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 start immediately independent life. According to scientists, as soon as they were born, they already knew how to swim perfectly and get their own food.
Mysterious “weevil whales”
Ichthyosaurs reached their greatest diversity in the Jurassic period, and became extinct at the end of the Cretaceous. Or maybe they didn’t become extinct? After all, there is the opinion of a number of scientists that the same ichthyosaurs were warm-blooded and could well adapt to changing conditions in the ocean. When these lizards that have survived to this day die or die, their remains sink to the bottom, scientists accordingly do not find them 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. I saw such an animal for the first and so far only time in my life. The fact that this is some kind of mutant is excluded. There were at least five of these long-faced, toothy “whales” with large saucer-like 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 for unusual creatures quite ordinary inhabitants of the ocean. 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: “The steep, rounded back of the head rose about 1.5 meters above the water, and the upper jaw stood out clearly white stripe, which, gradually expanding, stretched from the end of the muzzle to the corner of the mouth and was bordered below by a narrow black stripe... In profile, the head had a cone-shaped shape. 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 the senior researcher at the Cetacean Laboratory, Candidate of Biological Sciences A. Kuzmin, about the mysterious animal he had encountered. The scientist had known Titov for 10 years by that time, 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 including calves among them.
Kuzmin showed his acquaintance many photographs and drawings of various sea animals, but Titov never identified his “weevil.” But when an image of an ichthyosaur accidentally caught his eye, he said that it was very similar to the creatures he had met.
A very living fossil?
So, there are observations of trustworthy people who have seen unknown large marine animals that are very similar to ichthyosaurs that went extinct 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 by 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.” On the skepticism of scientists in Lately, of course, was greatly influenced by the discovery of lobe-finned fish, which was considered long extinct. If she managed to survive to this day, then why couldn’t the ichthyosaur do it?
French scientists concluded that ichthyosaurs were warm-blooded. This conclusion was made based on 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 by scientists suggests that ichthyosaurs could well have survived, especially since they did not feed on belemnites alone. It remains to be seen that more compelling evidence for the existence of these prehistoric animals will emerge. Fortunately, many sailors now have both cameras and video cameras, and we can well hope to see footage of a whole flock of big-eyed and toothy creatures from the Jurassic period frolicking in the waves.
Prepared by Andrey SIDORENKO
The Volga region preserves the remains of giants who plowed sea spaces during the time of the dinosaurs.
Early on an August morning in 1927, on the outskirts of Penza, not far from the ancient Mironositsky cemetery, a man appeared with a duffel bag over his shoulders - a political exile of modern times. Mikhail Vedenyapin. He went down into the Prolom ravine, to a small machine-gun firing range. There were no exercises that day, and in the ravine you could only meet boys running to collect shell casings.
Mikhail Vedenyapin had been living in Penza for two years, in exile. Before that, the tsarist courts exiled him, Admiral Kolchak promised to shoot him, and now the Bolsheviks did not like his views. And so the former professional revolutionary Socialist Revolutionary works as a statistician, in his spare time he writes notes in the magazine “Katorga and Exile” and wanders around the surrounding area in search of fossils. Like many scientists and simply curious people of those times, he has ten years left to live...
He walked along the slope of a deep ravine, picking up shells of mollusks from the ground that lived in a sea that had long ago disappeared - more than 80 million years ago. In one place, a sandy slope was broken by a machine-gun burst, and fragments of bones lay in the scree. The local historian collected them and climbed onto the cliff to see where it all fell out. It didn’t take long to search: huge bones were sticking out of the sand.
Vedenyapin immediately went to the local history museum. Alas, the geologist was away; the rest of the staff listened to the news without interest. Then the former Social Revolutionary gathered his friends and began excavations. However, the bones lay at a depth of seven meters - the excavation needed to be expanded. This required diggers, and for them - a salary. Vedenyapin turned to the authorities for help. The provincial executive committee met him halfway and gave him a hundred rubles. From funds intended for the improvement of the city.
Modern dinosaur museum in the village of Undory (Ulyanovsk region). Many plesiosaur bones have been found in local shale mines.
A few days later, the slope of the ravine gaped like a huge hole, and across Penza they crawled strange rumors. Someone claimed that a mammoth's grave was found near the cemetery. Someone said that the exile was digging up an ancient sea frog. In one church, during the service, the priest even told the congregation about the stone bones left over from a gigantic beast that did not fit into Noah’s ark. Rumors fueled curiosity, and people crowded into the ravine every day.
In the confusion, a couple of bones were stolen, and Vedenyapin asked the police to send a security detail. It didn’t help: several more vertebrae disappeared during the night. Then a Red Army patrol was posted in the ravine. Soldiers with three-line rifles were on duty around the clock. The main Penza newspaper Trudovaya Pravda also reined in the hooligans: between articles about treacherous priests and where the butter and sugar had disappeared, a call appeared: “We kindly request those present not to interfere with the work and comply with the demands of those leading the excavations!”
When 30 cubic meters of rock were dumped into the dump, the lower jaw appeared - long, with crooked teeth. It became clear that the remains of a giant marine reptile were found in the ravine - mosasaurus. The jaw was outlined in a trench. It turned out to be a kind of table on which lay a rock-covered bone. They did not take it out for fear of breaking it, and they sent a telegram to the Academy of Sciences to send specialists.
Mosasaurus tooth from a private collection, Cretaceous layers of the Saratov region. Photo: Maxim Arkhangelsky
In early September, two preparators from the Russian Geological Committee arrived in Penza and, according to the newspaper, immediately “began work on exposing the mosasaurus and excavating it.” It was necessary to remove the bones before the slope melted due to rains. And the shooting range had been idle for half a month. In a couple of days, the find was cleared of the rock. 19 large teeth, flattened on the sides, protruded from the jaw. Three more teeth lay nearby. There was nothing else.
The jaw was packed in a large box and taken out on a cart to be sent to Leningrad. A plaster copy was then donated to the regional museum. As it turned out, the remains belonged to a giant who lived at the end of the era of dinosaurs - the Hoffmann mosasaurus (Mosasaurus hoffmanni), one of the last sea lizards. Mosasaurs were real colossuses.
But they were not the only ones who lived in the Central Russian Sea, which existed on the territory of Central Russia in Mesozoic era. During the Jurassic and Cretaceous periods of this era, many dynasties of lizards were replaced. The bones of these leviathans are found not only in Penza, but also in the Moscow region, on the Kama and Vyatka, but most of them are in the Volga region - a giant cemetery of sea giants.
The sea came to the eastern edge of Europe about 170 million years ago, in the middle Jurassic period. “The general rise in sea levels during the Mesozoic era gradually led to the fact that the eastern part of Europe found itself under water. Then it was not yet a sea, but rather a bay, a long tentacle stretching from the south into the interior of the mainland. Later, the waves of the Boreal Sea moved from the north to the continent.
On the territory of the present Volga region, the bays met and formed a sea, which geologists called the Central Russian Sea,” says a senior researcher at the Geological Institute Russian Academy Sciences Mikhail Rogov. The western coast of the Central Russian Sea passed where Voronezh now stands; in the east it was bordered by the islands of the Urals. Thousands of square kilometers went under water - from the future Orenburg steppes to Vologda and Naryan-Mar.
Penza Georgiasaurus (georgiasaurus pensensis) Georgiasaurs grew up to 4-5 meters in length. Judging by the size and proportions of the limbs, they were quite strong swimmers and lived in the open sea. These lizards ate mainly small fish and cephalopods, although they may not have disdained the carrion floating on the surface of the sea. Their teeth are versatile: they can both pierce and tear prey.
The sea was shallow, no more than a few tens of meters deep. Numerous archipelagos and shallows rose from the water, teeming with fry and shrimp. There was noise on the islands coniferous forests, dinosaurs roamed, and the water element was conquered by swimming lizards.
In the Jurassic period sea predators, occupying the top of the food pyramid were ichthyosaurs and plesiosaurs. Their bones are found in shales on the banks of the Volga. Flat slate slabs that look like a giant stone book, often dotted with prints and shells as thickly as this page is with letters. The bones of lizards were especially often found in the first third of the last century, when an energy famine came to the country and the Volga region switched to local fuel - oil shale. Like mushrooms after rain, grandiose underground labyrinths of mines have appeared in Chuvashia, Samara, Saratov and Ulyanovsk regions.
Unfortunately, the miners were not interested in fossils. Usually the skeletons were destroyed during blasting, and the debris, along with the waste rock, went to the dump. Scientists have repeatedly asked miners to preserve the bones, but this has helped little. Director of the Paleontological Institute of the USSR Academy of Sciences, Academician Yuri Orlov, recalled how during an expedition he visited the workers at the mine and told them for a long time about the enormous value of ancient bones.
“Finds like yours serve as decoration for museums,” he said confidentially. To which the chief engineer replied: “Only stupid people go to museums...”
Clidastes. These lizards hunted cephalopods, fish and turtles. With their own length of up to five meters, they were not interested in large prey. Apparently, they mastered the technique of underwater flight, cutting through the water like penguins and sea turtles, and were excellent swimmers.
Some finds were still preserved, thanks to dedicated local historians. One of these enthusiasts was Konstantin Zhuravlev. In 1931, not far from his hometown Pugachev in the Saratov region began to develop oil shale - first in open pit mining, then in mines.
Soon, broken bones, broken fish prints and shells appeared in the dumps. Zhuravlev began to frequently visit the mine, climbed onto the dumps and talked with the workers, explaining to them how important the fossils were. The miners promised to take a closer look at the rock and, if they come across something interesting, to notify the museum. Sometimes, in fact, they notified - but rarely and late. The local historian collected almost the entire collection himself.
Mostly he came across the remains of ichthyosaurs. Over the course of several years, Zhuravlev found many scattered teeth and vertebrae of two ichthyosaurs - Paraophthalmosaurus savelievsky(Paraophthalmosaurus saveljeviensis) and ochevia, later named after the discoverer (Otschevia zhuravlevi).
These were medium-sized lizards. They grew to three to four meters in length and, judging by the proportions of their bodies, were good swimmers, but probably preferred to hunt from ambush. At the moment of the throw, they may have developed a speed of up to 30-40 kilometers per hour - quite sufficient to keep up with small fish or cephalopods, their main prey.
One day a real giant escaped from Zhuravlev. At the end of the summer of 1932, he learned that miners, while digging a tunnel, for several days came across huge vertebrae of the lizard - they were called “carriages”. The miners did not attach any importance to this and threw everything away. Only one “stroller” survived, which was given to a local historian. Zhuravlev calculated that the destroyed skeleton reached 10-12 meters in length. Subsequently, the vertebra disappeared, and it is impossible to verify the calculations. However, there are also skeletons of 14-meter fish lizards in the world.
To match these giants were Jurassic plesiosaurs. Their remains are much less common than the bones of ichthyosaurs, and usually in the form of fragments. One day Zhuravlev picked up a half-meter-long fragment of the lower jaw from a dump, from which fragments of 20-centimeter teeth were sticking out.
Moreover, the surviving teeth were located in the back of the jaw, and one can only guess what kind of palisade adorned the mouth of this plesiosaur (the front teeth are much larger). The skull itself was apparently three meters high. A person would fit in it like in a bed. Most likely, the jaw belonged Liopleurodon russian(Liopleurodon rossicus) - one of the largest marine predators in the entire history of the Earth.
Lioprevrodon
“They grew up to 10-12 meters long, weighed 50 tons, but, judging by some bones, there were larger individuals, including in the Volga region,” says Maxim Arkhangelsky, associate professor at Saratov State University. - Unfortunately, there are no complete skeletons or skulls in the collections. It's not just that they are rare. Sometimes they were simply destroyed during oil shale mining.”
Soon after the end of the Great Patriotic War An expedition from the Paleontological Institute discovered mine dumps in Buinsk ( Chuvash Republic) and Ozinki ( Saratov region) fragments of the skulls of two Liopleurodons. Each fragment is the size of a child.
Probably, the large skeleton found in the early 1990s at a mine near Syzran also belonged to Liopleurodon. Cracking open the shale, the combine's bucket hit a huge block. The teeth scraped its surface with a grinding sound, and sparks rained down. The worker climbed out of the cabin and examined the obstacle - a large nodule from which black bones, as if charred, were sticking out. The miner called the engineer. The work was suspended and local historians were called in. They photographed the skeleton, but did not remove it, deciding that it would take a lot of time. The mine management supported them: the face stood idle for a day already. The find was lined with explosives and blown up...
New times
Liopleurodons lived at the very end of the Jurassic period, when the Central Russian Sea reached its greatest size. “Several million years later, in the Cretaceous period, the sea broke up into separate, often desalinated bays and then left, then returned for a short time. A stable basin remained only in the south, reaching the borders of the present Middle and Lower Volga regions, where a grandiose archipelago stretched: many islands with lagoons and sandbanks,” explains paleontologist, professor at Saratov University Evgeniy Pervushov.
By that time, sea lizards had undergone great changes. The ichthyosaurs that swarmed the Jurassic seas almost became extinct. Their last representatives belonged to two genera - platypterygium(Platypterygius) and sveltonectes. A year ago, the first Russian sveltonectes(Sveltonectes insolitus), found in the Ulyanovsk region, is a two-meter fish-eating lizard.
Platypterygium was larger. One of the largest fragments was found 30 years ago in the vicinity of the Saratov village of Nizhnyaya Bannovka. It was with difficulty that the narrow and long front part of the skull was pulled out from the high Volga cliff. Judging by its size, the lizard reached six meters in length. The bones turned out to be unusual. “Extensive depressions are visible on the frontal part of the skull, and a number of holes are visible on the lower jaw. Dolphins have similar structures, and they are associated with echolocation organs. Probably, the Volga lizard could also navigate in the water by sending high-frequency signals and catching their reflection,” says Maxim Arkhangelsky.
But neither these nor other improvements helped the ichthyosaurs regain their former power. In the middle of the Cretaceous period, 100 million years ago, they finally left the arena of life, giving way to their long-time competitors - plesiosaurs.
Long neck
Ichthyosaurs lived only in water of normal salinity; desalinated bays or lagoons oversaturated with salt were not suitable for them. But the plesiosaurs didn’t care - they spread across a variety of sea basins. In the Cretaceous period, long-necked lizards began to predominate among them. Last year, one of these giraffe lizards was described from Lower Cretaceous deposits - Abyssosaurus Natalia(Abyssosaurus nataliae). Its scattered remains were dug up in Chuvashia. This plesiosaur received its name - Abyssosaurus (“lizard from the abyss”) due to the structural features of its bones, which suggest that the seven-meter giant led a deep-sea lifestyle.
In the second half of the Cretaceous period, among plesiosaurs, giant elasmosaurs(Elasmosauridae) with an unusually long neck. They apparently preferred to live in shallow coastal waters, warmed by the sun and teeming with small animals. Biomechanical models show that elasmosaurs moved slowly and, most likely, like airships, hung motionless in the water column, bending their necks and collecting carrion, or fishing for passing fish and belemnites (extinct cephalopods).
We have not yet found complete skeletons of elasmosaurs, but individual bones form large clusters: in some places in the Lower Volga region, from one square meter you can collect a “harvest” of several teeth and half a dozen vertebrae the size of a fist.
Short-necked animals lived together with elasmosaurs. plesiosaurs polycotylides(Polycotylidae). The skull of such a lizard was found in a small Penza quarry, where gray-yellow sandstone was mined and crushed. In the summer of 1972, a large slab with a strange convex pattern on the surface came across here. The workers were delighted: there was clay and puddles all around, and they could throw the stove at the change house and clean the dirt from the soles of their boots. One day, a worker, wiping his feet, noticed that strange lines formed a whole picture - the head of a lizard.
After some thought, he called the local museum. Local historians arrived at the quarry, cleared the slab and were amazed to see an almost complete imprint of the skull, spinal column and front flippers of the plesiosaur. To the question: “Where is the rest?” - The workers silently nodded towards the crusher. "Rug" moved to the museum. The bones were fragile and crumbled, but the imprints remained. Based on them, a new, so far the only species of Russian polycotylides was described - the Penza Georgiasaurus pensensis.
Last year, paleontologists, thanks to a discovery by scientists at the Natural History Museum in Los Angeles, finally discovered that plesiosaurs were viviparous reptiles.
But it was not plesiosaurs that became the main marine predators of the end of the dinosaur era. The true masters of the seas were mosasaurs, whose lizard ancestors descended into the sea in the middle of the Cretaceous period. Perhaps their homeland was precisely the Volga region: in Saratov, in an abandoned quarry on the slope of Bald Mountain, a fragment of the skull of one of the earliest mosasaurs was found. At the beginning of the 20th century, a complete skeleton of this lizard was apparently dug up in the Saratov province. But it was not scientists who found it, but peasants.
They broke out the blocks with bones and decided to sell them to a glue factory. Such factories were smoking all over the country. There, glue, soap and bone meal for fertilizer were made from the remains of cows, horses and goats. They also did not disdain fossil remains: a Ryazan bone factory once bought four skeletons of big-horned deer for processing. But only Saratov men thought of using a petrified lizard for soap...
By the end of the Cretaceous period, mosasaurs settled throughout the planet: their bones can now be found everywhere - in the American deserts, in the fields of New Zealand, in the quarries of Scandinavia. One of the richest deposits was discovered in the Volgograd region, not far from the Polunin farmstead, right on the collective farm melon patch.
Among the cracked lumps hot earth, near the watermelons lie dozens of rounded teeth and vertebrae of mosasaurs. Among them, the huge teeth of the Hoffmann mosasaurs, similar to browned bananas, stand out especially - the same one, next to which almost all other Cretaceous lizards looked like dwarfs.
Khans and kings of the Mesozoic era
The Hoffmann mosasaurus could be considered the largest Russian lizard, if not for the strange finds that are occasionally found in the Volga region. Thus, in the Ulyanovsk region, a fragment of the humerus of a Jurassic plesiosaur was once dug up - several times larger than usual. Then in Jurassic deposits In the Orenburg region, on the slope of Mount Khan’s Tomb, a piece of a hefty “thigh” of a plesiosaur came across. The length of these two lizards apparently approached 20 meters.
That is, they could be compared in size to whales and were largest predators throughout the history of the Earth. Another time, near an abandoned shale mine, a vertebra the size of a bucket was found. Foreign experts considered it to be the bone of a huge dinosaur - titanosaur. However, one of the famous Russian specialists According to extinct reptiles, Saratov professor Vitaly Ochev suggested that the vertebra could belong to a giant crocodile, up to 20 meters long.
Unfortunately, scattered fragments are not always suitable for scientific description. It is only clear that the subsoil of the Volga region holds many mysteries and will present more than one surprise to paleontologists. The skeletons of the planet's largest sea lizards may also be found here.
National Geographic No. 4 2012.
Thanks to the finds recent years The study of sea lizards of the Mesozoic, which for a long time remained in the shadow of their distant terrestrial relatives - dinosaurs, is experiencing a real renaissance. Now we can quite confidently reconstruct the appearance and habits of giant aquatic reptiles - ichthyosaurs, pliosaurs, mosasaurs and plesiosaurs.
The skeletons of aquatic reptiles became known to science among the first, playing important role in the development of the theory of biological evolution. The massive jaws of a mosasaurus, found in 1764 in a quarry near the Dutch city of Maastricht, clearly confirmed the fact of the extinction of animals, which was a radically new idea at that time. And at the beginning of the 19th century, discoveries of skeletons of ichthyosaurs and plesiosaurs made by Mary Anning in southwestern England provided rich material for research in the field of the still emerging science of extinct animals - paleontology.
In our time marine species reptiles - saltwater crocodiles, sea snakes and turtles, and Galapagos iguana lizards - make up only a small proportion of the reptiles living on the planet. But in the Mesozoic era (251-65 million years ago) their number was incomparably greater. This was apparently facilitated warm climate, which allowed animals unable to maintain a constant body temperature to feel great in water, an environment with a high heat capacity. In those days, sea lizards roamed the seas from pole to pole, occupying ecological niches modern whales, dolphins, seals and sharks. For more than 190 million years, they formed a “caste” of top predators, hunting not only fish and cephalopods, but also each other.
Back in the water
Like aquatic mammals- whales, dolphins and pinnipeds, sea lizards descended from air-breathing land-based ancestors: 300 million years ago, it was reptiles that conquered land, managing, thanks to the emergence of eggs protected by a leathery shell (unlike frogs and fish), to move from reproduction in water to reproduction outside aquatic environment. Nevertheless, for one reason or another, one or another group of reptiles at different periods again “tried their luck” in the water. It is not yet possible to accurately indicate these reasons, but, as a rule, the development of a new niche by a species is explained by its unoccupied position, the availability of food resources and the absence of predators.
The real invasion of lizards into the ocean began after the largest Permian-Triassic extinction event in the history of our planet (250 million years ago). Experts are still arguing about the causes of this disaster. Moving forward different versions: fall of a large meteorite, intense volcanic activity, massive release of methane hydrate and carbon dioxide. One thing is clear: over a period of time that is extremely short by geological standards, out of all the diversity of species of living organisms, only one in twenty managed to avoid becoming a victim of an environmental disaster. The deserted warm seas provided great opportunities for the “colonizers,” and this is probably why several groups of marine reptiles arose in the Mesozoic era. Four of them were truly unparalleled in number, diversity and distribution. Each group - ichthyosaurs, plesiosaurs, their relatives the pliosaurs, and mosasaurs - consisted of predators that occupied the top of the food pyramids. And each of the groups gave birth to colossi of truly monstrous proportions.
The most important factor that determined the successful development of the aquatic environment by Mesozoic reptiles was the transition to viviparity. Instead of laying eggs, females gave birth to fully formed and fairly large young, thereby increasing their chances of survival. Thus, life cycle the reptiles in question here were now completely in the water, and the last thread connecting the sea lizards with the land was torn. Subsequently, apparently, it was this evolutionary acquisition that allowed them to leave shallow waters and conquer the open sea. Not having to go ashore removed size restrictions, and some marine reptiles took advantage of gigantism. Growing up big isn't easy, but once you've grown up, try to beat him. He will offend anyone himself.
Ichthyosaurs - bigger, deeper, faster
The ancestors of fish-lizard ichthyosaurs, who mastered the aquatic environment about 245 million years ago, were small inhabitants of shallow waters. Their body was not barrel-shaped, like those of their descendants, but elongated, and its bending played an important role in movement. However, over the course of 40 million years, the appearance of ichthyosaurs changed significantly. The initially elongated body became more compact and ideally streamlined, and the caudal fin with a large lower blade and a small upper one in most species was transformed into almost symmetrical.
ABOUT family ties Paleontologists can only guess about ichthyosaurs. It is believed that this group separated very early from the evolutionary trunk, which later gave rise to such branches of reptiles as lizards and snakes, as well as crocodiles, dinosaurs and birds. One of the main problems still remains the lack of a transitional link between the terrestrial ancestors of ichthyosaurs and primitive marine forms. First known to science fish lizards are already completely aquatic organisms. It is difficult to say what their ancestor was.
The length of most ichthyosaurs did not exceed 2–4 meters. However, among them there were also giants, reaching 21 meters. Such giants included, for example, Shonisaurs, who lived at the end Triassic period, about 210 million years ago. These are some of the largest marine animals that have ever lived in the oceans of our planet. In addition to their enormous size, these ichthyosaurs were distinguished by a very long skull with narrow jaws. To imagine a shonisaurus, as one American paleontologist joked, you need to inflate a huge rubber dolphin and greatly stretch its face and fins. The most interesting thing is that only the young had teeth, while the gums of the adult reptiles were toothless. You may ask: how did such colossi eat? To this we can answer: if Shonisaurs were smaller, then one could assume that they chased prey and swallowed it whole, as do swordfish and its relatives - marlin and sailfish. However, twenty-meter giants could not be fast. Perhaps they fed themselves with small schooling fish or squid. There is also an assumption that adult shonisaurs used a filtration apparatus like a whalebone, which allowed them to strain plankton from the water. By the beginning of the Jurassic period (200 million years ago), species of ichthyosaurs appeared in the seas, relying on speed. They deftly pursued fish and swift belemnites - extinct relatives of squids and cuttlefish. By modern calculations, the three- to four-meter ichthyosaur stenopterygius developed a cruising speed no less than one of the fastest fish, tuna (dolphins swim twice as slow) - almost 80 km/h or 20 m/s! In water! The main propellant of such record holders was a powerful tail with vertical blades, like those of fish.
In the Jurassic period, which became the golden age of ichthyosaurs, these lizards were the most numerous marine reptiles. Some species of ichthyosaurs could dive to depths of up to half a kilometer or more in search of prey. These reptiles could distinguish moving objects at such a depth due to the size of their eyes. So, the diameter of the eye of Temnodontosaurus was 26 centimeters! Only the giant squid has more (up to 30 centimeters). The eyes of ichthyosaurs were protected from deformation during rapid movement or at great depth by a peculiar eye skeleton - supporting rings consisting of more than a dozen bone plates developing in the shell of the eye - the sclera.
The elongated muzzle, narrow jaws and shape of the teeth of fish lizards indicate that they ate, as already mentioned, relatively small animals: fish and cephalopods. Some species of ichthyosaurs had sharp, conical teeth that were good for grabbing nimble, slippery prey. In contrast, other ichthyosaurs had broad teeth with blunt or rounded tips to crush the shells of cephalopods such as ammonites and nautilids. However, not so long ago, the skeleton of a pregnant female ichthyosaur was discovered, inside which, in addition to fish bones, they found the bones of young sea turtles and, most amazing of all, the bone of an ancient seabird. There is also a report of the discovery of remains of a pterosaur (flying lizard) in the belly of a fish lizard. This means that the diet of ichthyosaurs was much more diverse than previously thought. Moreover, one of the species of early fish lizards discovered this year, which lived in the Triassic (about 240 million years ago), had serrated edges of the rhombic cross-section of its teeth, which indicates its ability to tear off pieces from prey. Such a monster, which reached a length of 15 meters, had practically no dangerous enemies. However, for unclear reasons, this branch of evolution stopped in the second half of the Cretaceous period, about 90 million years ago.
In the shallow seas of the Triassic period (240–210 million years ago), another group of reptiles flourished - the nothosaurs. In their lifestyle, they most closely resembled modern seals, spending part of their time on the shore. Nothosaurs were characterized by an elongated neck, and they swam with the help of a tail and webbed feet. Gradually, some of them replaced their paws with fins, which were used as oars, and the more powerful they were, the more the role of the tail weakened.
Nothosaurs are considered the ancestors of plesiosaurs, which the reader knows well from the legend of the monster from Loch Ness. The first plesiosaurs appeared in the mid-Triassic (240–230 million years ago), but their heyday began at the beginning of the Jurassic period, that is, about 200 million years ago.
At the same time, pliosaurs appeared. These marine reptiles were closely related, but they looked different. Representatives of both groups - a unique case among aquatic animals - moved with the help of two pairs of large paddle-shaped fins, and their movements were probably not unidirectional, but multidirectional: when the front fins moved down, the rear fins moved up. It can also be assumed that only the front fin blades were used more often - this saved more energy. The hind ones were put to work only during attacks on prey or rescue from larger predators.
Plesiosaurs are easily recognized by their very long necks. For example, in Elasmosaurus it consisted of 72 vertebrae! Scientists even know skeletons whose necks are longer than the body and tail combined. And, apparently, it was the neck that was their advantage. Although plesiosaurs were not the fastest swimmers, they were the most maneuverable. By the way, with their disappearance, long-necked animals no longer appeared in the sea. And one more interesting fact: the skeletons of some plesiosaurs were found not in marine, but in estuarine (where rivers flowed into the seas) and even freshwater sedimentary rocks. Thus, it is clear that this group did not live exclusively in the seas. For a long time, it was believed that plesiosaurs fed mainly on fish and cephalopods (belemnites and ammonites). The lizard slowly and imperceptibly swam up to the flock from below and, thanks to its extremely long neck, snatched the prey, clearly visible against the background of the light sky, before the flock rushed to its heels. But today it is obvious that the diet of these reptiles was richer. The found skeletons of plesiosaurs often contain smooth stones, probably specially swallowed by the lizard. Experts suggest that it was not ballast, as previously thought, but real millstones. The muscular section of the animal’s stomach, contracting, moved these stones, and they crushed the strong shells of mollusks and crustacean shells that had fallen into the womb of the plesiosaur. Skeletons of plesiosaurs with remains of bottom invertebrates indicate that in addition to species that specialized in hunting in the water column, there were also those that preferred to swim near the surface and collect prey from the bottom. It is also possible that some plesiosaurs could switch from one type of food to another depending on its availability, because a long neck is an excellent “fishing rod” with which it was possible to “catch” a wide variety of prey. It is worth adding that the neck of these predators was a rather rigid structure, and they could not sharply bend or lift it out of the water. This, by the way, casts doubt on many stories about the Loch Ness monster, when eyewitnesses report that they saw exactly long neck sticking out of the water. The largest of the plesiosaurs is the New Zealand Mauisaurus, which reached 20 meters in length, almost half of which was a giant neck.
The first pliosaurs, which lived in the late Triassic and early Jurassic periods (about 205 million years ago), closely resembled their plesiosaur relatives, initially misleading paleontologists. Their heads were relatively small, and their necks were quite long. Nevertheless, by the middle of the Jurassic period, the differences became very significant: the main trend in their evolution was an increase in the size of the head and the power of the jaws. The neck, accordingly, became short. And if plesiosaurs hunted mainly for fish and cephalopods, then adult pliosaurs chased other marine reptiles, including plesiosaurs. By the way, they didn’t disdain carrion either.
The largest of the first pliosaurs was the seven-meter Romaleosaurus, but its size, including the size of its meter-long jaws, pales in comparison with the monsters that appeared later. The oceans of the second half of the Jurassic period (160 million years ago) were ruled by Liopleurodons - monsters that may have reached 12 meters in length. Later, in the Cretaceous period (100–90 million years ago), colossi of similar sizes lived - Kronosaurus and Brachauchenius. However, the largest pliosaurs were the Late Jurassic period.
Liopleurodons, which inhabited the depths of the sea 160 million years ago, could move quickly with the help of large flippers, which they flapped like wings.
Even more?!
Recently, paleontologists have been incredibly lucky with sensational finds. So, two years ago, a Norwegian expedition led by Dr. Jorn Hurum extracted from permafrost on the island of Spitsbergen, fragments of the skeleton of a giant pliosaur. Its length was calculated from one of the skull bones. It turned out - 15 meters! And last year, in the Jurassic sediments of Dorset County in England, scientists had another success. On one of the beaches of Weymouth Bay, local fossil collector Kevin Sheehan dug up an almost completely preserved huge skull measuring 2 meters 40 centimeters! The length of this “sea dragon” could be as much as 16 meters! Almost the same length was the juvenile pliosaur found in 2002 in Mexico and named the Monster of Aramberri.
But that's not all. The Natural History Museum at Oxford University houses a gigantic lower jaw of a macromerus pliosaur measuring 2 meters 87 centimeters! The bone is damaged, and it is believed that its total length was no less than three meters. Thus, its owner could reach 18 meters. Truly imperial sizes.
But pliosaurs were not just huge, they were real monsters. If anyone posed a threat to them, it was themselves. Yes, the huge, whale-like Shonisaurus ichthyosaur and the long-necked Mauisaurus plesiosaur were longer. But the colossal pliosaur predators were ideal “killing machines” and had no equal. Three-meter fins quickly carried the monster towards the target. Powerful jaws with a palisade of huge teeth the size of bananas crushed bones and tore the flesh of victims, regardless of their size. They were truly invincible, and if anyone can be compared with them in power, it was the fossil megalodon shark. Tyrannosaurus rex next to giant pliosaurs looks like a pony in front of a Dutch draft horse. Taking a modern crocodile for comparison, paleontologists calculated the pressure that the huge pliosaur’s jaws developed at the time of the bite: it turned out to be about 15 tons. Scientists got an idea of the power and appetite of the eleven-meter Kronosaurus, who lived 100 million years ago, by “looking” into its belly. There they found the bones of a plesiosaur.
Throughout the Jurassic and much of the Cretaceous period, plesiosaurs and pliosaurs were the dominant ocean predators, although it should not be forgotten that there were always sharks nearby. One way or another, large pliosaurs went extinct about 90 million years ago for unclear reasons. However, as you know, a holy place is never empty. They were replaced in the seas of the late Cretaceous by giants that could compete with the most powerful of the pliosaurs. We are talking about mosasaurs.
Mosasaurus to mosasaurus - lunch
The group of mosasaurs, which replaced and perhaps supplanted the pliosaurs and plesiosaurs, arose from an evolutionary branch close to monitor lizards and snakes. In mosasaurs that completely switched to life in water and became viviparous, their paws were replaced by fins, but the main mover was a long, flattened tail, and in some species it ended in a fin like a shark’s. It can be noted that, judging by the pathological changes found in the fossilized bones, some mosasaurs were able to dive deeply and, like all extreme divers, suffered from the consequences of such dives. Some species of mosasaurs fed on benthic organisms, crushing mollusk shells with short, wide teeth with rounded tops. However, the conical and slightly bent back terrible teeth of most species leave no doubt about the eating habits of their owners. They hunted fish, including sharks, and cephalopods, crushed turtle shells, swallowed seabirds and even flying lizards, tore apart other marine reptiles and each other. Thus, half-digested plesiosaur bones were found inside a nine-meter-long tylosaur.
The design of the skull of mosasaurs allowed them to swallow whole even very big catch: like snakes, their lower jaw was equipped with additional joints, and some bones of the skull were articulated movably. As a result, the open mouth was truly monstrous in size. Moreover, two additional rows of teeth grew on the roof of the mouth, making it possible to hold prey more firmly. However, we should not forget that mosasaurs were also hunted. The five-meter-long Tylosaurus found by paleontologists had a crushed skull. The only one who could do this was another, larger mosasaurus.
Over 20 million years, mosasaurs rapidly evolved, giving rise to giants comparable in mass and size to monsters from other groups of marine reptiles. Towards the end of the Cretaceous period, during the next great extinction, giant sea lizards disappeared along with dinosaurs and pterosaurs. Possible reasons a new environmental disaster could be the impact of a huge meteorite and (or) increased volcanic activity.
The first to disappear, even before the Cretaceous extinction, were the pliosaurs, and somewhat later the plesiosaurs and mosasaurs. It is believed that this happened due to a violation food chains. The domino principle worked: the extinction of some massive groups of unicellular algae led to the disappearance of those who fed on them - crustaceans, and, as a consequence, fish and cephalopods. Marine reptiles were at the top of this pyramid. The extinction of mosasaurs, for example, could be a consequence of the extinction of ammonites, which formed the basis of their diet. However, there is no final clarity on this issue. For example, two other groups of predators, sharks and teleosts, which also fed on ammonites, survived the Late Cretaceous extinction event with relatively few losses.
Be that as it may, the era of sea monsters is over. And only after 10 million years will they appear again sea giants, but no longer lizards, but mammals - descendants of the wolf-like Pakicetus, which was the first to master the coastal shallow waters. Modern whales trace their ancestry from him. However, that's another story. Our magazine talked about this in the first issue of 2010.
Marine representatives have three orders of reptiles - turtles, lizards and snakes. Some sea snakes are not associated with land at all, even during breeding, since they are viviparous, never leave the sea and would be completely helpless on land. Morak turtles most They live in the open ocean, but return to the tropical coasts to reproduce; Only females come to land to lay eggs, and males never set foot on land after hatching and moving to the sea.
Sea lizards are more associated with land. An example is the Galapagos marine iguana Amblyrhynchus crisiatus. She lives in the surf on Galapagos Islands, climbs on rocks and feeds only on algae. Fourth Squad modern reptiles, crocodiles apparently do not have truly marine representatives. Living in salt water, Crocodylus porosus is associated mainly with estuaries; it feeds mainly on fish and probably cannot survive for long in the present marine environment.
^The kidneys of reptiles are not adapted to excrete excess salt, and it is excreted by salt-secreting (or simply salt) glands located in the head. Salt glands produce a highly concentrated fluid that contains mainly sodium and chlorine in concentrations much higher than in sea water. These glands do not function continuously like a kidney; they secrete their secretions only occasionally in response to a salt load that increases plasma salt concentrations. Similar glands are present in seabirds, in which they have been studied in detail.
In the wet lizard, the salt glands pour out their secretion into the anterior part of the nasal cavity, which has a ridge that prevents the liquid from flowing back and being swallowed. Sometimes, with a sharp exhalation, liquid is ejected from the nostrils in the form of small splashes. The Galapagos iguana feeds only on algae, which are similar in salt content to seawater. Therefore, the animal needs a mechanism to excrete salts in high concentrations (Schmidt-Nielsen, Fanne 1958). s'
sea turtles, both herbivores and carnivores, have large salt-secreting glands located in the orbits of both eyes. The gland duct opens in the posterior corner of the orbit, and the turtle, which has received a salt load, cries truly salty tears. (Human tears, which, as everyone knows, have a salty taste, are isosmotic with blood plasma. Therefore, the lacrimal glands in humans do not play a special role in the elimination of salt.)
^Sea snakes also secrete salty fluid when exposed to salt and have salt glands that open into the oral cavity, from where the secreted fluid is excreted (Dunson, 1968). Sea snakes are close relatives of cobras and are very poisonous, which somewhat slowed down the physiological study of their salt metabolism, which has a number of interesting aspects.
Although marine reptiles have a mechanism for excreting salt in the form of a very concentrated liquid, the question remains whether many of them actually drink water in significant quantities?
