Ancient turtles. An ancient legend about the origin of turtles. Types of sea turtles

Everyone associates turtles with the eternal slowness characteristic of these reptiles, but not everyone knows that turtles are one of the the most ancient representatives animal world of our planet. These creatures have been living on Earth for more than 220 million years, yes, they are the same age as extinct dinosaurs. The very name of the word “turtle” comes from the ancient Slavic “shard”, “tile”, similarly Latin name turtles - “testa” translates as “tiles”, apparently, turtles were nicknamed this way due to the similarity of their shells to the tiles themselves.

Turtle: description, structure, characteristics. What does a turtle look like?

Perhaps it is the shell of a turtle that is its most characteristic difference, a kind of turtle business card. For a turtle, it is, in fact, a sort of mobile home + a means of protection from enemies. The turtle shell consists of a dorsal (carapace) and abdominal (plastron) part. The carapace, in turn, consists of two parts, one of which is the internal armor, formed from bone plates, and the second is the outer part, consisting of horny scutes. In some species of turtles, the bony plates are covered with skin.

The shell of a turtle is very durable, so it can easily withstand a load exceeding the weight of the turtle itself by 200 times.

How big are turtles?

The size of a turtle and its weight differ greatly from the species, so in the turtle family there are both giant turtles with a weight of more than 900 kg and a shell size of 2.5 meters or more, and small turtles with a weight of up to 125 grams and a shell size no more than 10 cm.

Head and eyes of a turtle

The turtle's head is streamlined and medium in size. Such dimensions allow turtles, in case of danger, to quickly hide their heads inside an inaccessible shell. Although among them there are also species with big heads, which either fit poorly in the shell or don’t fit at all.

U land turtles the eyes are usually directed towards the ground, while in aquatic turtles they are located closer to the top of the head and directed forward and upward. The neck of many turtles is usually short.

The vision of turtles is well developed, even moreover, turtles, like people, have color vision, can distinguish colors, very few animals have this gift. Nature also gave them excellent hearing, allowing them to hear potential enemies from a distance.

Does a turtle have teeth? How many teeth does a turtle have?

Modern turtles, unfortunately, do not have teeth, but ancient turtles had them, those that lived during the era of dinosaurs, but over time they disappeared. Then how does a turtle eat? To bite and grind food, turtles use a strong beak; the surface of this beak is covered with rough protuberances, which practically replace teeth for turtles. The tongue of turtles is short; it serves exclusively for swallowing food, but not for capturing it, and as a result, does not protrude outward.

Limbs and tails of turtles

All turtles, without exception, have four legs. But the very structure of these paws depends on the type and habitat of the turtle. The paws of land turtles have a flattened shape, they are adapted for digging soil and are quite powerful. U sea ​​turtles in the process of millions of years of evolution, the paws turned into real flippers for the convenience of swimming in the depths of the sea.

Also, almost all turtles have a tail. The tail of a turtle, like its head, is also capable of hiding in its shell. Moreover, what is interesting is that some turtles have a real pointed spike at the tip of their tail, which serves as another means of protection from enemies.

An interesting fact: some land turtles can molt with age, and their old skin peels off and falls off, both from the paws and sometimes from the shell.

How long do turtles live?

Turtles are truly long-lived even by our human standards, because they live many times longer than us humans. So average duration life of turtles in natural conditions can be 180-250 years.

The most old turtle in the world, named Jonathan, lives on the island of St. Helena and remembers (probably) the times of Napoleon, because the former emperor of France lived here in exile for some time.

Where do turtles live?

Turtles live in all tropical areas, as well as in some places with temperate climate. Sea turtles swim in the warm ocean spaces of the Pacific, Atlantic and Indian Ocean. They are only absent near the Arctic and Antarctica, which is natural, because all turtles love warmth.

Land turtles live in the steppes and semi-deserts of Africa, South and North America, Australia, Asia. In Europe they can be found in the south, in a number of southern countries: Greece, Italy, Albania.

What do turtles eat in the wild?

The diet of turtles directly depends on their species, habitat and lifestyle. Land turtles are practically vegetarians; their main food is tree branches, fruits and grass, mushrooms and vegetables. However, it was not in vain that we wrote practically, since in order to maintain the protein balance in their bodies, turtles can sometimes eat various small animals such as snails, slugs and worms. Land turtles also drink water with pleasure.

But the sea and freshwater turtles are already real predators, since their diet includes various small fish, snails, crustaceans (some sea turtles happily eat squid, cuttlefish and other shrimp). But also, the gastronomic preferences of aquatic turtles are not limited to living creatures; together with them they eat and plant foods: seaweed.

Interesting fact, there are species of sea turtles that eat poisonous jellyfish. From such food, the meat of the turtles themselves, in turn, becomes poisonous, which scares potential predators away from them. This is a gastronomic remedy.

Enemies of turtles

Speaking of enemies, in natural conditions the main enemies of a turtle are some predator birds(eagles, ), who grab small turtles, lift them up greater height, from there they throw them onto the stones and peck out their entrails from the split shell.

Interesting fact: the great ancient Greek playwright Aeschylus died an extremely ridiculous death, he was killed by a turtle that fell on his head. The eagle, having lifted the turtle to a height, mistakenly considered the playwright's bald head to be a large stone suitable for breaking the turtle's shell.

Death of Aeschylus by an eagle and a turtle.

As for giant turtles, given their weight and size, they have no enemies in nature. Even people are increasingly treating these majestic, long-lived creatures with due respect.

When does a turtle hibernate?

Yes, turtles, like some other animals, tend to hibernate, during which all life processes in their body slow down for a while. This usually happens in winter, and hibernation for heat-loving turtles living in temperate latitudes, allows them to survive the winter cold without problems.

How to determine the sex of a turtle

The gender difference in turtles is so weakly expressed in appearance that it is sometimes difficult to determine whether this turtle is a “boy” or a “girl.” However, if you approach this issue with due attention, you can identify a number of signs that help determine the sex of a turtle.

1. Shell; in females the shell has a more elongated shape than in males.

2. Plastron, also known as the lower part of the shell. If you turn the turtle over, you can see that in females the lower part of the shell (the one closest to the anus) is flat, while in males it is slightly concave.

3. Tail, males have a tail that is longer and wider at the base, while “lady turtles” have a straight and short tail.

4. Claws, in males they are usually longer on the forelimbs than in females.

Types of turtles, photos and names

The turtle family is divided into two suborders, divided by the way turtles retract their heads into their shells:

• Hidden-necked turtles fold their heads into shells in the shape of the letter S.
• Side-necked turtles hide their heads in one of their front paws.

Also, according to their habitat, all turtles are divided into land and sea turtles, which in turn are divided into freshwater turtles, living in rivers and lakes, and marine turtles, living in the seas and oceans.

Below we take a closer look at some of the most interesting views turtles.

She's a turtle. These are real giant turtles, weight Galapagos tortoise can exceed 400 kg, the length of the shell reaches up to 1.9 m. These turtles live on the Galapagos Islands, which gave them their name.

This is already a small representative of land turtles, the length of the Egyptian tortoise shell is no more than 10 cm. They have a yellow-brown color of the shell. This turtle lives in northern Africa and the Middle East.

Is not big turtle, living respectively in Asia, has a rounded shell and is colored yellow-brown with dark spots. The average size of the shell of this turtle is 10 cm. It is also one of the most popular types of turtles for home keeping.

She's a turtle. It is of medium size, the length of the shell is 0.7 m, with a weight of up to 50 kg. The shell of this turtle is high and dome-shaped. The pattern of the shell shows a spotted pattern, similar to the color of a leopard. The leopard tortoise lives in Africa.

It is notable for being the smallest turtle in the world. The length of its shell is no more than 10 cm, with a weight of up to 165 grams. Lives in South Africa.

Types of freshwater turtles

This small turtle lives in waters of the USA and Canada. It has an interesting olive-green or black shell color and leathery membranes between the toes.

This small turtle lives in the waters of Europe and a number of Asian countries; the length of its shell is 35 cm and its weight is 1.5 kg. It has a brown-brown or olive-colored shell, and also a very long tail, like for a turtle.

So named due to the presence of a bright red spot on the head. The length of the shell of this turtle is 30 cm. They live red-eared turtles in both Americas, in the USA, Mexico, Colombia, Venezuela and a number of other countries.

Its characteristic feature is the presence of a cruciform plastron and long tail, covered with small thorns. It is of medium size, the weight of this turtle reaches up to 30 kg. It lives in the USA and southern Canada; it survives the winter cold in hibernation.

Types of sea turtles

She's a real carriage. The shell of this turtle is colored brown tones with a pattern in the form of multi-colored spots. The front flippers of this turtle are equipped with two claws. This turtle lives in almost all oceans, with the exception of cold waters near the poles.

Notable for being the largest turtle in the world. Only the span of its front flipper-like paws reaches 2.5 meters. Its weight is more than 900 kg, and its shell length exceeds 2.6 meters. The surface of this turtle's shell is covered with a dense layer of skin (hence the name). It lives in tropical regions of the Indian, Atlantic and Pacific oceans.

It is also a rather large turtle, its weight reaches up to 450 kg with a shell length of 1.5 m. It has an olive or green color of the shell, which, however, may have stripes white and dark spots. Its shell is small in height and oval in shape, and its surface is covered with large horny scutes. This turtle's head has a lot of big sizes than other relatives, and therefore does not hide inside the shell. It lives in tropical areas of the Atlantic and Pacific oceans.

Reproduction of turtles

The mating season for turtles occurs at different times depending on the species. However, in all turtles it occurs in a similar way: the males stage real battles for the right to mate with the female. How do turtles fight? It’s very simple, the land ones try to turn the enemy over with a blow from their shell, and the water ones hit and bite each other with their beaks. Only after driving away a potential rival does the male turtle begin courting his “lady,” forcing her to take a position convenient for the actual mating.

Some time after mating, the female turtle lays spherical or ellipsoidal eggs, from which small turtles will be born. Turtles dig special holes for their eggs, and sometimes even use the nests of crocodiles.

From 1 to 200 eggs can be laid at a time (depending on the species). Also the duration incubation period can last from 2 months to six months or more.

After hatching, small turtles begin to struggle for survival; not all of them will survive to adulthood; young turtles are an excellent target for various predators, especially birds of prey.

How to care for a turtle at home

Keeping turtles at home Lately is very popular, and both land and aquatic turtles are kept. And why not, because caring for them is extremely simple, and turtles themselves are unpretentious creatures. True, all of the above is true for small turtles, since keeping large turtles in the house will not be entirely appropriate.

So, what are the rules for caring for turtles? First, in the turtle's habitat, you need to keep a thermometer to monitor the air temperature and a thermometer to monitor the water temperature (if it is an aquatic turtle in an aquarium).

The water in an aquarium for turtles must either be purified using filters, or if there are none, then changed every day. Maintaining hygiene for aquatic turtles involves removing algae from their shells. But land turtles need to be bathed daily in warm water, washing away dirt and food debris from them. Also, in winter, it is advisable to irradiate turtles a little with the rays of a quartz lamp, thus creating a kind of sunbathing.

What to feed a turtle at home

Turtles need to be provided balanced diet. Land turtles can be fed cabbage, dandelion, apple pulp, cucumbers, and tomatoes. To satisfy the need for protein food, they can be given boiled chicken eggs and vitamin supplements.

Feeding aquatic turtles will be a little more difficult, because they need small animals; you can feed them with dried daphnia, bloodworms, earthworms, boiled chicken or beef. They will not mind eating various insects, cockroaches, and small aquarium fish.

Adult turtles need to be fed once a day, young turtles twice a day and a so-called fasting day once a week.

• It was the turtles that were the first to fly around our moon satellite on board the experimental research probe launched Soviet Union back in 1968.
• Turtle meat is an expensive and delicious product in some cuisines around the world.
• Turtles are also present in heraldry, in the depiction of the coats of arms of some cities.
• Despite the fact that turtles do not pose a danger to humans, there are exceptions, for example, male leatherback turtles can confuse a swimmer with a female, grab them with their paws and drag them to the bottom.
• The sex of turtles in eggs is determined by temperature environment. With more low temperatures Males are born; at higher levels, females are born.

Turtle, video

And in conclusion, an interesting documentary about turtles.

Turtles are one of the oldest animals on Earth. They have adapted to survive not only on land, but also in water. Since ancient times, people have endowed turtles with mystical, magical properties. For many peoples, turtles are a symbol of wisdom and ancestral, family ties, and continuity of generations.

Turtles are one of the most unpretentious animals, so many are happy to keep them at home, receiving incomparable pleasure from observing their habits and way of life.

Some people collect turtle figurines, believing that by doing so they bring harmony to their home and stability and longevity to family ties. I can also count myself among the people who value family foundations and traditions. And therefore, in order to contribute to the longevity of my family, I also collect figurines of turtles and am interested in the characteristics of these animals, as well as the stories associated with them.

A little history

The turtle is a symbol of material existence: the turtle’s shell is seen as the vault of heaven that arose on flat earth; a direct mediator between heaven and earth, a symbol of everything universal.

The turtle symbolizes the slowness of life, its smooth flow and is associated with everything slow-moving and slow.

The cult of the turtle was more typical of the traditions of peoples Central Asia, where the turtle was looked at as the embodiment of the god Vishnu, the guardian of the worlds. It was believed that Mount Mandra was located on her back, around which she wound giant snake Ananta, one end of which is pulled by the gods (devas), the other by demons (asuras).

In Chinese tradition, the turtle is a symbol of immortality, which is associated with its surprisingly long life span. The turtle is also a symbol of wisdom, as evidenced by numerous bas-reliefs and images. In ancient history, the turtle is a sacred animal of the goddess of love Venus and the god of nature Pan

Among the Indians, the function of turtles is to be responsible for newborn children, so they are directly related to childbirth and babies.

Ancient people believed that the world rested on its back huge turtle, which laid the foundation for the Earth, creating the first solid foundation in the ancient ocean.

Ancient legend about the origin of turtles.

Ancient Indian legend narrates: when the world was young, daring giants encroached on the rights of the gods, and a battle broke out between them. The wrath of the gods was terrible, and the surviving giants fled in panic. On the battlefield, only the shields of the fallen giants and those who fled remained. In order to prevent people from angering the gods in the future, and also for the sake of creating another miracle, they breathed life into these shields. And the shields spread across the ground, overgrown with paws, heads and tails, turning into turtles.

Types of turtles.

Turtles are the most famous reptiles on Earth. There are about 340 forms (species and subspecies) of turtles on our planet, some of which live on land (terrestrial turtles), some only in water (freshwater and marine), and the remaining both on land and in water are semi-aquatic. Turtles can be found in salty and fresh water, in forests, on the open sea and even on dry land, closer to deserts

Appearance.

Turtles as they are seen today appeared 200 million years ago, when humans did not yet exist and dinosaurs roamed the Earth.

In sea turtles, due to their constant life in water, their legs have turned into flippers. Freshwater turtles have a flattened, streamlined shell, legs with long sharp claws for tearing prey, and membranes have formed between their toes.

Land turtles are usually powerfully built, with thick legs and short, blunt claws. Some aquatic turtles have switched to life on land for the second time, but do not break their connection with water

Turtle shell is the most important distinguishing feature of all turtles It protects the turtle from injury, serves as protection from enemies, retains body heat, and gives strength to the turtle skeleton. The shell of a turtle consists of bone; its scutes are covered with horny plates on top. For fixation, the ribs, vertebrae, pelvic and shoulder girdles are fused with the shell. The appearance of the shells depends on the environment. In aquatic animals they are flat and flattened, in land animals they are denser and thicker. In the same species of turtles different conditions may be different

The more than 200 species of turtles that exist differ from each other in both size and body shape. The largest is the leatherback turtle. The length of its shell is about 2 m. The Australian snake-necked turtle is small - no more than 30 cm long.

What turtles live in Russia.

Among the two hundred species of living turtles, some are found in our country. True, on the lands of the ancestors of the Slavs there was only one species - marsh turtle, a secretive inhabitant of overgrown reservoirs. The Slavs called it “zhelvya,” but the turtle did not occupy a prominent place in their folklore, religion, or ideas. There are two types of land turtles in Russia: the steppe tortoise and the Mediterranean tortoise. Outwardly, they are almost no different, only in the number of claws on the front paws: the Mediterranean has five, the steppe has four. The Mediterranean is found in the Transcaucasian republics and Dagestan; it can also be found on the Caspian coastline.

Are all turtles scavengers?

A turtle moving on land does nothing to disprove the view that turtles trudge through life. But not all turtles are hoarders. Sea turtles swim at a speed of about 30 km/h. Anyone who has been bitten by a snapping turtle knows that, whether defending or attacking, it can lunge with lightning speed.

When does a turtle turn into an ice cube?

In Canada there is a motley turtle, which has perfectly adapted to the far from hot climate of this country. Scientists have found that in winter time she doesn’t just hibernate, but completely turns into an “ice”.

The female motley turtle lays eggs in the summer, for this she loose soil digs a shallow furrow. In the fall, the eggs hatch into babies. However, they are not at all in a hurry to leave their shelter, but burrow even deeper into the soil, while avoiding encounters with both predators and extreme cold.

By measuring the temperature in these depressions, scientists found that there too it drops to minus 8 degrees, but small turtles tolerate this too. It turned out that more than half of all the moisture contained in the animal’s body turns into ice during the winter, so that the baby becomes like stone.

Where did turtles come from?

Turtles are one of the few ancient inhabitants of the Earth who have survived to this day.

Scientists claim that turtles descended from primitive reptiles - cotylosaurs. The very first turtles did not yet know how to retract their heads and limbs into their shells, because there was nowhere else to retract them. The shell-house that all turtles wear now was not yet formed. Their backs were simply turned into a shell covered with shields. The turtles' backs hardened and eventually became covered with horny scutes.

The upper shield of turtle armor is called the carapace, and the lower shield is called the plastron.

Turtles appeared on our planet about 200 million years ago, and about 135 million years ago, that is, in the Cretaceous period, scientists believe there were about 26 families of turtles on Earth (currently there are only 12 of them). Interestingly, turtles have remained virtually unchanged since then.

The closest relatives of modern turtles, Proganochelis, lived in Europe and Asia during the Late Triassic period (200 million years ago). It is worth noting that these animals, like turtles, had a tortoiseshell-type shell and beak. However, unlike modern turtles, Proganochelis did not have the ability to retract its head and limbs into its shell. However, they did not need this, since the head and legs of these reptiles were protected by hard scales.

Currently, there are 5 suborders of turtles, 3 of which are major: side-necked, cryptonecked and shieldless turtles. The other two suborders trace their origins to the cryptonecked turtles.

Some researchers classify the leatherback sea turtle as a special suborder of shieldless turtles, which differ from all other turtles not only in appearance, but also internal structure. Their shell, unlike that of other turtles, consists of a layer of small interconnected polygonal bony plates and is not fused to the spine and ribs.

In addition, the shell of the leatherback sea turtle is covered on top with skin with many small horny scutes. Moreover, with age, the skin becomes smooth and even. Many scientists believe that the ancestors of leatherback sea turtles were Archelon ischyros, animals that lived in the seas of South Dakota more than 65 million years ago. The fossilized remains of this giant (weighing about 3 tons, up to 4 m long) were found in the flatlands of the central states of the United States, where the waters of the Niobar Sea once stretched. It is worth noting that the evolution of turtles belonging to different suborders proceeded independently of each other, therefore in their structure and appearance there are very significant differences.

For example, side-necked and cryptonecked turtles appeared during the Middle Triassic, and the names of these reptiles indicate the ways in which they retract their heads under their shells. Side-necks fold their neck horizontally, bending it like an S and pressing it to the base of the limb, while hidden-necks fold it vertically.

Side-necked turtles have remained virtually unchanged for millions of years, as evidenced by the remains of the inhabitants found during excavations. Cretaceous period.

Currently, side-necked turtles are found only in Southern Hemisphere our planet: in Africa, Australia, New Guinea, Madagascar and South America.

Hidden-necked turtles, or cryptodires, are the most common group of turtles. It is believed that during the Middle Triassic period these animals lived only in swampy areas, but over time they adapted to live both on land, including desert and forest-steppe areas, and in water. In addition, their survival was facilitated by the fact that they ate a variety of food - plant and animal.

About 150–200 million years ago, in the Jurassic period, a suborder of soft-bodied turtles emerged from the group of cryptonecked turtles. These animals adapted to life in water, and gradually their shell became less massive, thanks to which the animals gained the ability to swim with sufficient high speed. Currently soft-bodied turtles are considered the fastest of all types. They are able to move with high speed not only in aquatic environment, but also on land.

The ancestors of snapping turtles lived in the Eocene, that is, approximately 38–55 million years ago. Having examined the fossil remains of these animals, scientists came to the conclusion that the shell of ancient snapping turtles was quite soft, and therefore the reptiles could not defend themselves in the event of an attack by predators and, in order not to become their prey, preferred to attack first, showing aggressiveness unusual for turtles. By the way, modern snapping turtles behave in a similar way. That is why they are not kept in home terrariums.

The so-called horned turtle is considered one of the most unusual in the evolutionary chain of turtles, about which scientific circles have already for a long time the disputes do not stop. The fact is that some scientists classify horned turtles as... dinosaurs, while most scientific experts classify these extinct animals as reptiles.

The appearance of the horned turtles was truly terrifying. The animals reached 5 m in length. These reptiles had a huge tail, the same length as the shell, with two rows of bone spikes, clearly used for protection from enemies. The turtle's skull was triangular in shape, with long, slightly blunted horns directed sideways and backwards, which the animal also used for protection. There are holes in the front and back of the shell into which the animal can remove its limbs and head in case of danger. In some species of turtles, movable parts of the shell can completely cover one or both openings if necessary.

Several different families of freshwater turtles probably tried to explore the sea. Some people succeeded. In the middle Jurassic period The first freshwater turtles appeared. All older turtles were apparently terrestrial. At the end of the Jurassic period, some freshwater turtles made an attempt to go to sea. At first they inhabited the coastal zone, their limbs had not yet transformed into flippers. The first group of coastal sea turtles (Plesiochelyoidea) became extinct at the beginning of the Cretaceous period. Around the same time, real sea turtles with flippers appeared - protostegids (Protostegidae). They lived until the end of the Cretaceous period and went extinct along with the dinosaurs.

Protostegids were the only sea turtles throughout almost the entire Cretaceous period. Representatives of other groups that have survived to this day (Cheloniidae, Dermochelyidae) appeared 40–50 million years later. At this point, protostegids were dominant and cosmopolitan, while cheloniids and dermocheliids were probably restricted to coastal areas or inland seas. Apparently, they went to sea independently of the protostegids and were the third or even fourth attempt at the development of the seas by turtles.

The evolution of protostegids lasted tens of millions of years, during which they populated the seas of Europe, the USA, and Russia. These turtles chose a fairly common environmental strategy; Over time, they increased in size and became gigantic in order to feel safe. It was the protostegids that gave birth to the most giant turtle throughout the history of the Earth - the famous Archelon. In many books there is an old photograph of the skeleton of this turtle, where a man is standing next to it. In fact, the photo is a little confusing: the man in the photo, paleontologist George Wieland, was very short. Archelon was not as gigantic as you might think when looking at the photo. But still its size is colossal: the span of its front flippers was four and a half meters.

The most ancient representative of protostegids is considered to be a reptile from the Early Cretaceous, Barremian-Aptian deposits of Colombia - a large turtle Desmatochelys padillai with a skull about 30 cm long and a meter-long shell. The skull of another ancient protostegid was found by fossil collectors about ten years ago in Ulyanovsk region. They say she had a beak “like a parrot.” The skull was sent to Moscow for study, but it has not yet been described. According to the elder research fellow I. G. Danilova, the skull, judging by the photographs, also belonged to a turtle of the type Desmatochelys.

Based on materials from Russia, only one species of Mesozoic sea turtle has been described so far. The history of its study is curious. In the mid-eighties, biology students from Leningrad State University went on a summer internship to the Forest on Vorskla nature reserve in the Belgorod region, where they studied the forest ecosystem, collected herbariums and insects. The leader L.A. Nesov decided to combine business with pleasure and took them out for additional paleontological practice. Not far from the reserve there are Lebedinsky and Stoilensky quarries, where they mine iron ore, simultaneously revealing layers of sandstones of Cretaceous age (Albian-Cenomanian), and the sandstones are rich in the remains of marine animals. The students were lucky to find several interesting specimens, including the country's first protostegid bones: a piece lower jaw and plastron bones with a stellate shape characteristic of protostegiids. Nessov described the remains as the new kind- Russian teguliskaf ( Teguliscapha rossica). It was an early representative of protostegids, still small: about half a meter in length. Its description was published in the non-trivial collection “Comprehensive studies of biogeocenoses of forest-steppe oak forests” in 1986. As a result, the publication went unnoticed and fell out of sight of most paleontologists for thirty years.

Then the finds stopped, and only recently in Russia it was possible to find new remains of sea - and already giant - turtles from the end of the Cretaceous period. The most important discoveries were made in the spring and autumn of 2017. Excavations took place in the steppe ravines on the border of the Saratov and Volgograd regions, in the “beach deposits” of the Cretaceous period (see picture of the day Mosasaurs of the Volga region). Students from the Saratov State Technical University, hired as labor, spent almost the entire day digging in vain. There were no finds, although inexperienced excavators mistook each sandstone nodule for dinosaur bones. Finally, one young man successfully dug into the sand with a shovel and turned out a stone the size of a zucchini. At first it was mistaken for sandstone, but the stone successfully split in the middle, and the spongy structure of a reddish bone appeared on the chip. The find turned out to be half of a turtle's humerus. An hour later, another student dug up an unusual shovel. Both bones were soon identified. They belonged to protostegids, although indeterminate to genus. Their more accurate systematic position currently being confirmed.

That same summer, several more turtle bones were found in the rafters. One plate of the shell showed bite marks: someone tried to eat the turtle, and possibly successfully.

Saratov protostegids were of very respectable size. From the tip of the nose to the tip of the tail, their length exceeded two meters. There are no traces of horny grooves (scutes) on the bone plates - apparently, the shells of the Volga protostegids were already covered with soft skin, although, perhaps, the traces were simply not imprinted.

It is difficult to judge the diet of extinct turtles. Most turtles have no teeth, and their jaws are covered with horny sheaths. Unfortunately, horny sheaths are not preserved in the geological record, and bone structures only partially reflect their structure. Protostegids probably ate like modern sea turtles and occupied a rather unusual ecological niche. Modern sea turtles eat anything except fish because they cannot catch it: their heads are too large and their necks are too slow. Unlike sea turtles, freshwater turtles are omnivores, and some are specialized specifically for fishing. Modern sea turtles feed on algae and shellfish. The leatherback turtle preys on clumsy jellyfish. Protostegids probably fed mainly on molluscs - ammonites and oysters.

However, among the extinct sea turtles there were also extremely unusual forms. For example, ocepechelone ( Ocepechelon) from Late Cretaceous deposits (Maastrichtian) of Morocco. She has a gigantic skull - 70 centimeters in length. Apart from the skull, nothing survived. The upper jaw of the turtle (the lower jaw was not found) forms a massive tube about 6 centimeters in diameter. The turtle probably sucked in fry and krill through it. Perhaps she “vacuumed” the prey in dense thickets algae or among corals. Judging by the skull, she had strong jaw muscles to create a powerful suction thrust.

The locomotion of ancient turtles is also judged mainly by analogy with modern ones, which swim using the “underwater flight” technique: with their front flippers they write “eights”, like owls, and their back flippers are used as a rudder. Perhaps protostegids also swam this way. It is possible to calculate and clarify the biomechanics, since complete skeletons of protostegids are known, but no one has done this yet.

Saratov protostegids turned out to be close to American sea turtles and became another confirmation of the hypothesis that extinct reptiles of the Mesozoic, like modern cetaceans, easily crossed the spaces of the World Ocean. Similar genera spread throughout the planet, and the species diversity of sea turtles was generally low.

Illustration © Andrey Atuchin.

Anton Nelikhov

MOSCOW, 23 Aug- RIA News. Scientists have found the remains of an unusual reptile in southern China, which allowed them to find out what the first ancestors of the Earth's turtles, who lived in future Asia at the beginning of the Jurassic period, looked like. Their findings and photographs of the remains of the "grandfather of all turtles" were presented in the journal Nature.

"The history of turtles has been one of the main mysteries in paleontology for many decades. The discovery of the remains of Eorhynchochelys greatly clarified the situation and helped us understand how these reptiles arose," said Olivier Rieppel from the Fields Museum in Chicago (USA).

As scientists note, the history of turtle evolution remains largely a mystery. All known species extinct turtles, except for the most ancient Odontochelys and Proganochelys, already possessed a full-fledged shell. It was not clear how these reptiles turned their ribs into “armor” and acquired special respiratory muscles that allowed them to breathe without their help.

The situation did not become clearer even after the discovery of odontochelys in 2008 - the lower half of the shell was already present in this reptile. This made scientists wonder how the evolution of turtles proceeded and when their ancestors turned into a kind of modern “tortilla”.

Rieppel and his colleagues solved this problem by discovering the remains of extremely unusual creature, which resembles both primitive archosaur lizards and turtles, studying early Jurassic sediments that formed in southern China about 220 million years ago.

Carrying out excavations in the town of Heshangjing in Guizhou province, scientists came across a two-meter skeleton of a reptile, finding it almost at the same point where the first remains of Odontochelys were found, but in deeper layers of sediment.

This creature, which received the name Eorhynchochelys sinensis, or "dawn-beaked tortoise of China", was noticeably different in appearance from Odontochelys and other primitive "tortillas" of antiquity. In particular, it had a very long and thin tail, and the ribs of this reptile had not yet fused into a shell.

On the other hand, they have already taken on a disc-shaped shape, and the jaws of Eorhynchochelys sinensis have turned into a kind of beak, which all turtles have today. This fact, as Rippel notes, has become very important milestone from the point of view of studying the evolution of these reptiles.

In the past, many paleontologists believed that turtles were descendants of anapsids, older and more primitive lizards that did not have holes in their skulls. The discovery of Eorhynchochelys sinensis shows that this is not the case and confirms the data genetic research, indicating the family ties between turtles and modern birds and crocodiles.