The Permian or Permian period is the sixth and last period of the era. It lasted from 298 million years ago to 251 million years ago, that is, for 47 million years. Perm ends the era with the Paleozoic, after which a new era begins - and the first period of the Mesozoic - the Triassic. In order not to get confused in eons, eras and periods, use the geochronological scale, which is located as a visual clue.
The main events of the Permian period were the further evolution and development of life forms on the planet, as well as the Permian extinction, which is considered the greatest mass extinction of all time. It is also worth noting that Permian is the only geological system among all eons, eras and periods that received a Russian name. The Russian name "Perm" was given to this period for the reason that the tectonic structure of this period was discovered near the city of Perm in 1841. Today this structure is called the Cis-Ural marginal foredeep. It is also present in the Urals and the East European Plain.
Scientists claim that in the Permian period the climate was very similar to the climate of modern Earth. The evolutionary development of representatives of flora and fauna continued. In the Triassic period, for the first time in history, beetles appeared. The first finds of beetles date back to 270 million years ago. Also in this period, insects such as caddisflies and scorpions appear. Archaeologists have also discovered the remains of many extinct animals, including Scutosaurus, Istranocevia, Dwynius, Titanophoneus, Ulemosaurus, Anteosaurus, Mormosaurus, Dimetrodon, and others.
Permian extinction
The Permian Mass Extinction is the largest mass extinction in the history of planet Earth. There has never been such a large-scale extinction of living organisms. As a result of the global catastrophe, 96% of all marine species and 73% of terrestrial species became extinct. The Permian extinction is considered the only one among the five mass extinctions that also led to the mass extinction of insects - 57% of the genera and 83% of the species of the entire class of insects. Extinction occurred at the border of the Paleozoic and Mesozoic, and two periods - Permian and. Such huge losses in the animal world occurred in just 60 thousand years. It was because of the global extinction of species that scientists drew a line after which the animal world of the Earth began its evolution after incredible losses. Scientists note that the restoration of the biosphere after the Permian period took a longer time than after other mass extinctions - from 5 to 30 million years.
The mass extinction opened the way for new species of animals, in particular, archosaurs, from which many types of dinosaurs were formed, and later - the first birds. Also, after the mass extinction, the first mammals appeared.
The reasons for the extinction have not been reliably elucidated. The main versions: the fall of an asteroid or several asteroids, which led to climate change; hung volcanic activity, since during this period the largest supercontinent Pangea in history was finally formed. Also, such versions are put forward as: a sudden release of methane from the bottom of the sea, the acquisition by archaea of the ability to release large volumes of methane, changes in ocean currents, changes in sea level, oxygen deficiency, changes in the chemical composition of water.
Animals of the Permian period
Anteosaurus
Archosaurus
Biarmosuchus
Venyukovia
Dimetrodon
Inostrancevia
Kamakops
Megavitsia
Mormosaurus
Scutosaurus
Titanopters
Titanophones
Ulemosaurus
Estemmenosuchus
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Permian period, about 290 million years ago. The time has come when the gigantic parts of the earth's firmament once again collided with each other, forming the boundless supercontinent Pangea, stretching from pole to pole. For millions of years, the continents have traveled vast distances, sometimes gathering together, sometimes moving away to different parts of the globe. Quite shortly before the Permian period, they were united into two huge continents: Laurasia and Gondwana, but now these giants have met. Several million years before this significant event, the poles of the Earth were covered with ice caps. Large-scale glaciation began, the planet's climate became cold and remained so until the end of the Permian period. Only at the border of two eras - the Paleozoic and the Mesozoic (about 250 million years ago) - did the glaciation decrease and the world became warmer again. It was in the middle of this period that the animal lizards, or therapsids, appeared.
The very first of them are known from deposits of the mid-Permian period (about 270 million years ago). Pelycosaurs are considered the ancestors of these peculiar reptiles. Some of them were distinguished by a huge skin "sail" located on the back, which was necessary for the lizard to regulate body temperature. Pelycosaurs appeared in the Carboniferous and still lived side by side with animal lizards, but were forced out by their more perfect descendants and died out at the end of the Permian. The Beast Lizardmen had an amazing future...
Beast Lizard Time
Changing, since the Carboniferous period, the climatic conditions of the Earth have made their own adjustments to the composition of the terrestrial fauna of vertebrates. If amphibian labyrinthodonts (better known as stegocephals) flourished in the Carboniferous period, then the onset of a cold snap, which ended with glaciation, forced them to thoroughly make room for the throne of the dominant tetrapods. For the life of these amphibians, a warmer and more humid climate was needed, which would provide them with favorable living conditions. It was in the Carboniferous period that pelycosaur reptiles appeared, controlling their body temperature by means of a thermostatic sail. But they did not resist, disappearing into Perm. But their more perfect descendants - animal lizards spread all over the planet. Their skeletons are not found only in Australia. A number of adaptations to the new conditions of existence allowed the animal lizards to displace both the labyrinthodonts and their progenitors, the pelycosaurs.
Most reptiles move on bent legs, clinging to the ground. And the animal lizards switched to a different method: their paws were almost perpendicular to the plane of the body, that is, they straightened considerably. This position of the paws made it possible to move quickly. Animal lizards have become active predators, capable of overtaking both labyrinthodonts and various fellow reptiles. For this, it was necessary to have a high level of metabolism. And it can be provided provided that the animal is warm-blooded! On a number of bones of animal lizards, imprints of many skin blood vessels were found, which were rich in the skin of these reptiles. From this follows the conclusion that, most likely, many animal lizards were covered with wool - an undoubted sign of warm-bloodedness. Remained on the imprints of therapsid skin and numerous pits, which paleontologists consider a sign of the presence of glands. Horny scales, characteristic of the vast majority of reptiles, were not present in animal lizards. The skin was protected from drying out by numerous glands and was covered to varying degrees with wool. Which makes them very similar to mammals!
The beginning of a cold snap forced the cold-blooded animals to make room. Some of them have died out. The warm climate zone on the planet, of course, remained, but it remained in the region of the equatorial belt. The unification of the continents into a single supercontinent made the climate in the center of Pangea sharply continental, that is, very contrasting. The days were warm and the nights cold, like in modern deserts. This was especially true of the second half of the Permian period. Having acquired warm-bloodedness and greater mobility, the animal lizards became the dominant predators of the end of the Permian period. Unlike cold-blooded animals, they could hunt even at night. Among them appeared both carnivorous animals and vegetarians.
Taste preferences
The first animal lizards were small predators that hunted small prey. As time went on, therapsids occupied more and more new ecological niches. Highly specialized predators, and vegetarian reptiles, and omnivores appeared among them. Of the large predators, foreigners are well known today (body length - 2.5 m).
Scientists have studied this predator well and believe that it specialized in a specific prey - clumsy pareiasaurs. Most of the time, pareiasaurs spent in the water, like modern hippos. Inostrancevia did not just sneak up from the shore and overtake pareiasaurs in the water, she swam well! This predator, like most carnivorous animal-like lizards, had one common feature. On both sides of the mouth protruded large, curved fangs that sat in the upper jaws. They were the first to pierce the body of the victim.
But titanophoneus (preview reconstruction) and siodon loved to dive for fish. The teeth of these animal lizards were arranged in such a way that the slippery prey could not escape from the mouth.
In Proburnetia, despite the fangs, food preferences were very diverse. This is an omnivore.
The diet of another small animal lizard, venyukovia, is not entirely clear. At first it seemed that the teeth belonged to some giant rodent, but they could not grind solid plant food. Venyukovia obviously ate rough food. It is possible that with the help of teeth, a heavy lower jaw and powerful jaw muscles, venyukovia split the shells of mollusks. But perhaps she preferred the soft, succulent stems of succulents.
The variety of body sizes of animal lizards is also striking. Some of them were not inferior in size to modern rhinos. Estemmenosuchus deinocephals looked like very large hippos 4 m long. Standing in the water, they slowly plucked and sent coastal algae to the stomach. This group of lizards was called "deinocephals", which translates as "terrible-headed", not by chance. On the skull of Estemmenosuchus there were several large bony outgrowths directed in different directions. Why they were needed is still unclear. Another group of animal lizards was also not inferior in size to modern African inhabitants. These are dicynodonts, or "two-canine". In addition to the two "fangs" protruding from the mouth, these animals had no other teeth. With their help, dicynodonts tore up the soil in search of roots, which they rubbed with the keratinized edges of the jaws. Some dicynodonts were very small animals, such as the Permian dicynodont, or the Triassic Listrosaurus (their body length did not exceed 1 m). But already at the beginning of the Triassic period, such herbivorous giants as cannemeieria appeared, the body length of which reached 3 m.
Other animal lizards, on the contrary, were no larger than a hare or a rat. Many of them ate insects. These animals outwardly were already quite similar to real mammals!
Step by step
Animal lizards are considered the progenitors of all mammals. However, to become a mammal, warm-bloodedness and wool alone are not enough. New transformations, step by step, removing them from the lizards and bringing them closer to the animals, were associated with a way of life. First of all, it is getting food. By becoming active predators that could easily catch up with reptiles and hunt at night, animal lizards gained another advantage - a secondary palate. The fact is that in reptiles, the nasal openings lead to the oral cavity, which creates inconvenience when eating: either eat or breathe. Already in the most ancient therapsids, a rudimentary bony septum appears, separating the nasal openings from the oral cavity. In the process of evolution, this septum increased until, in the latest animal lizards, it divided the oral cavity into two: the actual oral and nasal. This has affected the nutrition of animals. If earlier reptiles had to bite off a piece of food and swallow it faster so as not to suffocate, now the food could stay in the mouth longer. It was possible to chew it properly, which increased the absorption of various nutrients. But in Paleozoic reptiles, the teeth were adapted for cutting or biting off food and served as a blade. For chewing, completely different teeth were required. Thus began the differentiation of the entire dental system.
The jaw apparatus was also improved. The lower jaw began to work more efficiently for grinding food. The number of bones in it has decreased. The bones that were no longer part of the lower jaw did not just disappear. They decreased in size and formed a completely different organ - the organ of hearing. These bones evolved into the malleus, anvil, and stirrup, the auditory bones common to all mammals. However, this did not happen immediately. The hearing organ of many animal lizards was still very primitive, but millions of years passed, and it increasingly approached the animal prototype.
The formation of the nasal cavity served as an impetus for the development of the sense of smell. And along with the development of the sensory system in the nasal cavity, additional sense organs appeared that are well developed in modern mammals - vibrissa whiskers. Their existence in therapsids is quite convincingly proved by some paleontologists. The complication of the sense organs, in turn, influenced the development of the brain, because in order to receive and analyze information from the outside world at a higher level, it was necessary to develop the corresponding zones and lobes of the brain.
It would seem that what connects the appearance of wool and the differentiation of the dental system, chewing food and the complication of the structure of the brain? In fact, they are all links in the same chain. Animal lizards have a not yet complete partition in the oral cavity. They could slowly swallow food, chewing it. The crushed food began to come in large quantities and was well absorbed. Due to this, the intensity of metabolism and activity of the animal increased. To constantly maintain this level of metabolism, you need a regular intake of food. It’s good if the animal is herbivorous and can graze for days, devouring vegetation, but if it’s a predator, you have to look for and catch prey, because the first animal lizards were just carnivores. This requires a keen sense of smell and sensitive hearing, as well as more complex behavior, which is associated with the development of the brain. In addition, the weather is not too warm. And in this case, you need a woolen cover, which reduces the heat transfer from the body of the animal.
Using all these innovations, an adult beast lizard could successfully maintain warm-bloodedness, but what about newborn animals? Small animal lizards did not develop in the womb, but, like all reptiles, in an egg. For a period they were protected by the eggshell and consumed the reserves that were in the egg. A newborn pangolin needed the care of parents who would still feed him food. The way out of this situation was the peculiarity of the structure of the skin, rich in glands. All these glands were originally, most likely, sweat glands. Over time, some of them began to produce a secret enriched with fats and proteins, which was the prototype of mammalian milk. After carefully studying the structure of the jaw bones of animal lizards, some paleontologists have come to the conclusion that a number of therapsids had soft lips, which are necessary for sucking milk.
cherished border
Over time, the animal lizards became so similar to mammals that it was probably very easy to confuse them in appearance. Yes, and the structure of the body, they differed little from the animals. Where to draw the line between animal lizards and mammals? Scientists return to this issue from time to time. The boundary dilemma always arises in such transitional groups as beast lizards.
Most likely, it is necessary to decide which feature or group of features is the last step that leads to a different level of organization. Paleontologists agreed that the most important features of the organization of real mammals are the structure of the dental system, lower jaw and inner ear. It is authentically known that several groups of animal lizards, in terms of the level of organization, "came" to the border separating reptiles and mammals. Or maybe they didn't cross it alone. That is, it is quite likely that different mammals: monotremes, marsupials, real animals - originated from different groups of animal lizards! And it happened already in another era - the Mesozoic, in the Triassic period.
The eternal question
Why did the beast lizards become extinct? The answer is not to be found in the fall of a giant meteorite or the explosion of a supernova. The origins of this process, extinction, must be sought on Earth.
The Triassic became even hotter than the Late Permian. There was also Pangea. Deserts were common in the middle latitudes. Now cold-blooded animals could fight for the right to dominate in various communities.
Some of the Triassic beast lizards were huge vegetarians that fed near bodies of water. There were also therocephalic animal lizards, which had poisonous glands. But there were no large predators, so characteristic of the Permian fauna. On the contrary, small carnivorous cynodonts, or dog-toothed, flourished.
Their first representatives, for example, movements, appeared at the end of the Permian. These were the most highly organized animal lizards, in many ways resembling mammals. Some of them, like Cynognathus and, already Jurassic, Oligocyphus, were most likely burrowing animals.
There were no large predators among the animal lizards, because even more successful hunters than therapsids appeared on the evolutionary arena of life. At first it was thecodonts, and then their descendants - dinosaurs. Initially, among these reptiles there were predators, and predators who mastered a new way of hunting. They looked out and caught up with the victim on their hind legs. Yes, and they ran not on bent, but on straightened legs. And the metabolic rate of the new predators was no less high (in dinosaurs anyway) than that of the animal lizards. So therapsids lost the throne of "kings of nature" and moved into the category of small predators. Of course, animal lizards could now dart in modern forests, but another important event in the evolution of life took place - mammals appeared in the Triassic. They could not compete with dinosaurs and move into the category of large predators and herbivores. But on the other hand, animals have become very effective hunters among small animals. Thus, the more highly organized descendants ousted their ancestors from these positions as well. Beast lizards did not live until the beginning of the Cretaceous period. This was the end of the story of an amazing group of ancient reptiles.
Russian pantries
In Russia, the petrified bones of animal lizards were first discovered and described in the first half of the 19th century. But the fossil remains of these animals were very few until one important event for Russian paleontology took place. At that time, one of the richest localities of the Permian fauna was considered to be a reptile burial found in the sediments of the Karru semi-desert plateau in South Africa. Imprints of leaves of seed ferns and shells of freshwater mollusks were also found here. Professor Vladimir Prokhorovich Amalitsky also knew about this location. He believed that deposits of the same age could occur along the banks of the Malaya Severnaya Dvina River. The search was crowned with a small but undoubted success - it was possible to find shells of bivalve mollusks and imprints of leaves of seed ferns, very similar to South African ones.
Amalitsky suggested that the bones of ancient lizards could be found in the same place. The search continued for 15 years. And here is the long-awaited success! On the steep bank, among the light rocks, a dark layer of sandstone was clearly marked. It was here that numerous skeletons and individual bones of Permian reptiles were discovered, among which were the remains of animal lizards. It turned out that once on the site of the Malaya Northern Dvina, the waters of an ancient river flowed, into which rain streams carried the corpses of animals that lived on the shore. The composition of the Severodvinsk fauna resembled fossil reptiles found on the Karru Plateau. In 1929, in Tatarstan, near the village of Isheevo, on the banks of the Volga, layers of Permian age were discovered, which abounded in the skeletal remains of reptiles. After many years of excavations, it was possible to describe a number of amazing animal lizards. Among them was an overweight giant, whose body length reached 5 m, called Ulemosaurus. He was a herbivore. The clumsy animal lizard had almost no enemies. What was the surprise of scientists when it turned out that the moschops found in South Africa and the Isheevsky ulemosaurus were the same animal.
According to the rule of priority, the name moschops was retained for the animal lizard, since it was given earlier. Moschops was not the only animal lizard whose range occupied a significant part of Pangea. For example, the Lystrosaurus skeleton was found in the early Triassic deposits of Russia. But it turned out that at the very beginning of the Mesozoic era, listrosaurs also lived on the territory of today's Europe, as well as Asia (from South to East), South Africa and even Antarctica. Here, in Antarctica, at that time another animal lizard lived - a small predator - Trinaxodon, and the northern border of its distribution passed all in the same South Africa. Thus, it turned out that the richest skeletal pantries of animal lizards, which were studied by a whole galaxy of famous Soviet paleontologists, are stored in the earth layers of Russia.
Aleksey Pakhnevich, Candidate of Biological Sciences
Permian period (299.0 ± 0.8 - 251.0 ± 0.4 million years ago)
Rice. 2.7.1. Landscape of the Permian periodPermian geological period, Carboniferous- last period Paleozoic(Fig. 2.7.1). The Permian period is divided into two sections: lower and upper.
Climate of the Permian period characterized by pronounced zoning and increasing aridity. In general, we can say that it was close to modern. In any case, it had more similarities with the modern climate than with subsequent periods of the Mesozoic. At the beginning of the Permian, bacteria and fungi learned how to utilize wood, and the oxygen catastrophe of the Carboniferous period receded without breaking out properly. The main direction of the evolutionary process in the Permian period was the development by plants and animals of increasingly arid regions, while evolution proceeded very quickly and along many parallel directions.
The beginning of the Permian period was marked by glaciation on the southern continents and, accordingly, a decrease in sea level throughout the planet. However, with the advance of Gondwana to the north, the land warmed up, and the ice gradually melted. At the same time, part of the territory of Laurasia became very hot and dry, and vast deserts spread there. During this period, vertebrates begin to dominate, according to some data, up to 82% of all animal genera living at that time belonged to them. Vertebrate genera and families arose and died out very quickly in the Permian period, most Permian genera existed for only 10-20 million years.
Rice. 2.7.2. The sea of the Permian period In the Carboniferous period, crinoids were widely distributed on reefs. They formed bizarre underwater "gardens", clad in a strong shell. As before, the seas (Fig. 2.7.2) were inhabited by a wide variety of brachiopods. Some of them developed shells with zigzag edges, as a result of which both shell valves were more firmly connected to each other. Spiny brachiopods lived in the thickness of the silt, and brachiopods on stalks attached to any solid objects and even to the shells of other animals. However, now they all had to challenge food with new competitors - bivalve mollusks, the ancestors of modern Hungarians and mussels. Many bivalve mollusks have mastered a new habitat for themselves - bottom sediments. With the help of their strong muscular "legs" they dug into the silt. Bivalve mollusks fed through special tubes protruding to the surface. Some species have even learned to swim like modern scallops by snapping their shells shut and thereby pushing themselves forward.
As a result, the marine fauna of the Permian period was much poorer than that of the Carboniferous. Foraminifera are rare; the number of sponges, corals, and echinoderms is sharply reduced. There are new forms of brachiopods that live in our time in the Indian Ocean. Bryozoans continue to exist. They formed reefs. Ostracods and worm-like crustaceans have reached significant development.
Rice. 2.7.3. Parahelicoprion. The most prosperous class of fish in Perm is still cartilaginous fish, they include 6% of all Permian genera. The lion's share of cartilaginous fish are laminabranchial(5% of all births), these include sharks- cartilaginous fish with teeth twisted into a spiral (Fig. 2.7.3). Appear freshwater sharks. Decreasing quantity lobe-finned fish, now they are less than 2% of all births. Basically, these were not very large fish, up to 90 cm in length. Also in the Permian period there is a small amount whole-headed(their modern representative are chimeras).
ray-finned fish finally became a common class. In Perm, they include 5% of all genera, almost all small Permian fish - ray-finned. Continue to drag out a miserable existence acanthodes.
In the Carboniferous period, new formidable predators appeared in the seas. These were ammonites, relatives nautiloid. Most of them probably hunted just above the surface of the seabed, but some also ventured into the open sea. Powerful jaws of ammonites easily dealt with trilobites and others crustaceans. Subsequently, very spectacular fossils were obtained from ammonites. Their shells were decorated with a complex pattern of grooves and bulges, and the inner chambers were divided by plates, traces of which were preserved on the surface of fossil shells in the form of a set of grooves. Throughout the Permian period, patterns on ammonite shells became more diverse, and the grooves became more and more curled and wavy.
Rice. 2.7.4. Animal world of the Permian period Having found themselves among such dangerous predators, some "peaceful" amphibians began to acquire a hard shell. Their ridges were covered by bone plates, for which scientists called them "armored toads."
arthropods, so rapidly developing earlier, underwent a great decline in the population. As a result of the decrease in the oxygen contained in the atmosphere to a normal level, all their giant representatives died out.
At the beginning of Perm amphibians dominated both on land and in fresh water bodies (Fig. 2.7.4). With the beginning of the Permian period, amphibians become quite diverse. Small forms, a few centimeters in size, lived next to the giant ancestors of frogs, which reached the size of a bull. If in carbon quadrupeds accounted for about half of all vertebrates, in the Permian period their share increased to 69% of all genera.
Rice. 2.7.5. Archegosaurus. Amphibians differed not only in size, but also in lifestyle. They lived both in water and on land, feeding on insects and fish, algae and ferns. Adapting to land conditions, they spent less and less time in the water. In the Permian period, this class included 15% of all genera, the most successful group were temnospondyls(11% of all births). The most prosperous suborder of the Permian temnospondyls – Euskelia(3% of all births). These are rather thick and inactive animals with a massive head and a short tail. Length euskelium ranged from 40 cm to 2 m. Among the euskelii, it is especially interesting Platyhystrix, which has grown a folding sail on its back for thermoregulation - a unique case among amphibians.
In second place among temnospondyls worth a family archosaurids (archegosauridae) - large (from 1.5 to 9 m) freshwater creatures, in the adult state, practically do not differ from modern crocodiles(Fig. 2.7.5). Prionosuchus was the largest animal of the Permian period.
Rice. 2.7.6. Eriops. Less prosperous suborders of Permian temnospondyls include stereospondyls(up to 70 cm), zatrachydides other.
Another large group of amphibians, including 4% of all Permian genera, are - lepospondyls- medium-sized creatures from 25 cm to 1 m, many of which have completely or partially lost limbs.
Rice. 2.7.7. Diploceraspis. One of the most formidable predators of that era, eriops, had over 2 m in length (Fig. 2.7.6). Eriops hunted smaller amphibians and reptiles, and possibly fish. Very strange predators were diplocol and diploceraspis(Fig. 2.7.7) - flattened animals with huge boomerang-shaped heads and eyes directed upwards. Apparently, they were hiding in a layer of silt at the bottom of the reservoirs, waiting for the prey to swim right over their heads. No one really knows why the heads of these predators were so strangely shaped. Perhaps, in a fight, it was with their heads that they inflicted side blows on the enemy. Or maybe it was a kind of "hydrofoil" that helped the animal to rise up while swimming.
However, the climate was getting drier, and the amphibians, with their moist porous skin, had to take refuge in the few wet oases that remained among the deserts. Many of them have died out. And then a new group of animals, better adapted to arid habitats, began to spread rapidly around the globe - reptiles (reptiliomorphs). It was the most representative group quadrupeds- which no longer occupied 13% of all births, but 53%.
The first reptiles were small and looked like lizards. They fed mainly on arthropods and worms. But soon large reptiles appeared, preying on smaller ones. Over time, both predators and their prey acquired large and powerful jaws to fight numerous enemies, and strong teeth that sat firmly in the cells (like the teeth of modern mammals and crocodiles). Thus, the reptiles became larger and more ferocious.
reptiles in shape and body structure strongly resembled labyrinthodonts (stegocephalians). However, the most primitive representatives of this class were already much better adapted to the conditions of life on land (meaning the method of reproduction and development of embryos). While amphibians, like their ancestors - fish, multiplied by laying eggs in the water, reptiles began to lay their eggs directly on land. Larger than eggs, eggs had a significant supply of nutrients, which allowed the embryo to develop bypassing the larval stage. The young of reptiles differed from adults only in size, while the larvae of amphibians led an aquatic lifestyle, differing in their structure from adults in the same way that modern tadpoles differ from frogs. Laying eggs on land contributed to the formation of several shells in them. The shells protected the eggs from mechanical damage and drying out, and provided the embryo with air. The fibrous and calcareous shells protected the eggs from spreading, mechanical damage and bacteria penetration. The protein shell contained the main reserves of water. Part of it was released as a result of fat oxidation, part came from the outer shell. As the embryo developed, other shells arose.
Rice. 2.7.8. Pareyazvary. The evolution of reptiles took place very quickly, since there were no animals on land that could compete with them. Long before the end of the Permian period, reptiles displace stegocephalians. Primitive reptiles - cotylosaurs- gave numerous descendants who subsequently captured water, land and air. Size from a frog to a hippopotamus, they still had many signs of labyrinthodonts, in particular teeth and ribs, located from the neck to the tail, short massive limbs. But the structure of the skull, vertebrae, skin was already the same as that of reptiles.
A more complex organization compared to other reptiles had pareiasaurs(Fig. 2.7.8), the size of which reached 3 m. However, they also had skin bones in the shoulder girdle, characteristic of fish and amphibians. The skull of pareiasaurs was a solid bone box with holes for the eyes, nostrils, and parietal organ. They were herbivores and lived on the banks of rivers and lakes.
Rice. 2.7.9. Representative of pelycosaurs - Dimetrodon In the middle of the Permian period, they flourished cotylosaurs. At the beginning of the Triassic, they became extinct. More organized and specialized reptiles appeared - the descendants of cotilosaurs. Permian reptiles adapted to a variety of living conditions. Most groups of animals have become more mobile, and their skeletons have become lighter. They ate a variety of foods: plants, shellfish, fish.
Real ones appear predators - pelycosaurs(Fig. 2.7.9), on whose spines there were high ridges. In some reptiles, the limbs are lengthened, skin bones disappear. Arcs appear in the temporal region of the skull, to which a complex system of muscles was attached. The teeth of herbivores become flat, and such a four-meter predator as foreigners already had real fangs.
Among predatory reptiles, forms similar to modern wolves, hyenas, and martens appear. This suggests that the way of life of animals of that time and the present was similar.
All Permian reptiles are divided into two classes sauropsids – ancestors of modern reptiles and animal-toothed - mammalian ancestors.
Rice. 2.7.10. Representative of the pareiosaur Scutosaurus. they had neither hair nor sweat glands, but their skin easily keratinized, creating strong (or not so) armor. In addition, due to the peculiarities of metabolism, sauropsids tolerated water deficiency better. Sauropsids in Perm did not flourish as synapsids(see below), only 13% of Permian genera belong to sauropsids. The most extensive group of Permian sauropsids belongs to the subclass anapsids which are the ancestors of the current turtles, they include 8% of all Permian genera. The most extensive subclass parareptiles(according to other classifications - anapsid) in Perm were herbivores procolophones (procolophonia), this group includes, in particular, pareiasaurs(Fig. 2.7.10) - the next hippo-like creatures that replaced tapinocephalians eaten Gorgonops. Unlike tapinocephals, pareiasaurs acquired subcutaneous bone plaques that somehow protected the body from long saber-toothed fangs. The pareiasaurs reached a length of 3.5 m. In addition to the pareiasaurs, the procolophon order also included smaller lizard-like creatures.
Rice. 2.7.11. Captorhinids (Captorhinus). Another large group of parareptiles (anapsids) - captorhinids(2% of all Permian genera Fig. 2.7.11). This is the oldest detachment of anapsids, it was formed back in the Carboniferous, this includes lizard-like creatures up to 75 cm in length, mainly herbivores.
In Perm, a detachment separated from terrestrial anapsids mesosaurs(Fig. 2.7.12), these were the first reptiles to return to an aquatic lifestyle. Permian mesosaurs were small, reaching up to one meter in size. Mesosaurs had needle-like teeth. When the animal closed its jaws, they were inserted into the interdental spaces. Such teeth played the role of a sieve. The mesosaurus would pick up a full mouth of small invertebrates or fish, clench its jaws, strain out water through its teeth and swallow everything that was left in its mouth.
Rice. 2.7.12. Mesosaurus In addition to these several units, there were also other smaller ones up to 60 cm in size.
Second evolutionary branch sauropsid – diapsids, they include 5% of all Permian genera. Let us briefly consider the main groups of Permian diapsids. Areoscelides- one of the first attempts of evolution to make a terrestrial lizard. They flourished in the Carboniferous, and in the Permian period they gradually die out. archosauromorphs- ancestors of crocodiles, dinosaurs and birds. Relatively large (up to 2 m), in the appearance of some, something dinosaur-like begins to be vaguely guessed.
Rice. 2.7.13. Coelurosaurus. The first of the flying reptiles was coelurosaurus(Fig. 2.7.13), whose remains have been found in Europe and Madagascar. It appeared in the Permian period. Outwardly, he resembled a modern flying lizard - a flying dragon. Draco Volans, living in Southeast Asia, and perfectly planned by air. Coelurosaurus is a prime example of so-called evolutionary convergence, a process in which unrelated creatures acquire similar traits. Coelurosaurus reached 40 cm in length. It had very long ribs on its sides with a leathery film stretched between them. The span of these rigid "wings" reached 30 cm. The reptile's light skeleton and skull reduced the total body weight, and it had a crest on the back of its head that improved aerodynamic qualities.
In the Permian period, there were ancestors of lizards and snakes - lepidosauromorphs.
Primitive anthracosaurs which were a transitional link from amphibians to reptiles, have not yet died out in the Permian period, although they gradually fell into decay. These include 4% of all Permian births. They led a semi-aquatic lifestyle, reaching a length of 2-3 m, but most species were much smaller.
In addition to the listed groups of sauropsids, there were other less numerous orders in the Permian period.
As mentioned above, another large class of reptiles that lived in the Permian period were animal-toothed. Their teeth, like the teeth of mammals, differed in shape. They had incisors, fangs and tuberous molars. The lower jaw consisted of one dentary bone, and not several, as in fish, amphibians and typical reptiles. Like mammals, animal-toothed reptiles had a secondary bony palate that separated the nasopharynx from the oral cavity. This allowed the mammals to chew their food. Animals are similar to mammals also in the structure of the shoulder blades and pelvis. All this indicates that the mammal-toothed were the ancestors of mammals.
Rice. 2.7.14. Inostrancevia. By the end of the Permian period, a group of more mobile animal-like reptiles arose - the so-called Gorgonopsians(Fig. 2.7.14). In early reptiles, the legs were located on the sides of the body, as in many modern lizards. Therefore, they moved only waddle, and their bodies, when walking, bent from side to side. But in the Gorgonops reptiles, the legs grew under the body. This allowed them to take longer steps, and therefore run faster. Many Gorgonopsians were armed with huge fangs capable of tearing through the thick skins of armored reptiles.
Rice. 2.7.15. The representative of varanopseids is Varanodon. Animal reptiles, or synapsids, appeared on Earth towards the end of the Carboniferous period and were the most prosperous group of riptiliomorphs of the Permian period, which included up to 36% of all genera. These animals gradually evolved towards mammals - they grew fangs, hair and sweat glands, learned to keep a constant body temperature, etc. Unlike most other evolutionary trees, the synapsid evolutionary tree does not look like a spreading bush, but like a spruce twig that has a well-defined growth direction, and all side branches do not grow far. Therefore, we will consider the subgroups of synapsids not in descending order of generic diversity, but in the order in which they branched off from the “general line”.
The most primitive of them pelycosaurs(the only order of reptiliomorphs of the Carboniferous belonging to the class of synapids in Fig. 2.7.9), developed into many different species and became the largest and most common reptiles of that era. Most pelycosaurs had large teeth, and it can be concluded that they hunted big game. Some species have switched to plant foods. Plants are digested much more slowly, therefore, the stomachs of herbivorous pelycosaurs had to contain a lot of food for a long time. This means that these animals themselves must have increased in size. However, very soon, carnivorous reptiles (predators) became larger.
The oldest of them were caseasaurus occupying 3% of all births in Perm. In theory, they should have branched off in the Carboniferous, but their remains are known only from the Early Permian. Dimensions caseasaurs ranged from 1.2 to 6.1 m, weight reached 2 tons, most were herbivorous, but there was one insectivorous family. Caseasaurs include the largest land animals of the Perm, however, their large size did not save them from rapid extinction; in the second half of the Permian, they were eaten by Gorgonops, which will be discussed below.
The second branch, also separated from the "general line" of the Pelycosaur order back in the Carboniferous, is the family varanopseids(3% of all Permian genera Fig. 2.7.15). In the Permian, they grew noticeably (up to 1.5 m), but there were no other significant changes with them.
Ophiacodonts and Edaphosaurus flourished in the Carboniferous, and in the Permian they live out the remains of their century. The only interesting thing that happened to them was a giant ophiacodon 3.6 m long.
Rice. 2.7.16. Ivntosaurus. At the beginning of the Permian, the ancestors of mammals that appeared at the end of the Carboniferous sphenacodonts flourished (3% of all genera), they were the largest and most advanced predators of their time, the largest of them reached a length of 4.5 m.
Another more advanced detachment belonging to the class of synapsids, which appeared in the Permian period, were therapsids, they include 25% of all Permian genera. In therapsids, the limbs did not stick out to the sides, like in pelycosaurs and modern crocodiles, but were located almost vertically under the body, this allowed them to run, although not very fast - they still did not know how to bend the spine to speed up the run. Therapsids did not have scales or hair, and many had tactile hairs on their muzzles, much like whiskers on cats. The carnivorous therapsids had well-pronounced fangs. The first group that separated from the "general line" of the order of therapsids belonged to the genus biarmosuchus(4% of all births). These were predators ranging in size from 1 to 6 m, the largest of them - Ivantosaurus(Fig. 2.7.16), named after I.A. Efremov.
Rice. 2.7.17. Tapinocephalus, Struthiocephalus, Lycosuchus, Robertia and Bradysaurus. The next large suborder of therapsids were deinocephali(7% of all Permian births). These animals were distinguished by a very large skull with very thick bones. The largest infraorder of deinocephals were tapinocephali(5% of all Permian genera), most of them were herbivorous hippopotamus-like creatures 2.5-5 m in length and up to 2 tons in weight. A characteristic feature of herbivorous tapinocephals is a hefty frontal bone up to 30 cm thick. Most likely, tapinocephalians used it in much the same way that modern rams use horns. Tapinocephalians did not eat grass (there was practically no grass in the Permian period), but gnawed the lower branches of tree-like ferns or chewed half-rotted trunks. Tapinocephals did not have molars, they chewed food with their front teeth, this oddity is explained by the fact that tapinocephals (like all other animals considered up to this point) did not yet have a secondary palate separating the oral cavity from the nasopharynx, they could not chew and breathe at the same time. Tapinocephali(Fig. 2.7.17) - the first animals to acquire sweat glands, from that moment a folding sail on the back was no longer needed.
Rice. 2.7.18. Anteosaurus. Among the tapinocephalians, the titanosuchus family occupies a special place. Like wild boars, these creatures moved from a purely vegetarian diet to a more versatile diet, occasionally eating carrion and possibly preying on small, defenseless prey (such as the young of other tapinocephalians).
Another, not so prosperous family of the deinocephalic suborder was anteosaurs(Fig. 2.7.18). These were large predators, such as bears, from 2.5 to 6 m in length (including the tail), but relatively slender - no more than 600 kg. Interestingly, instead of a palate, they developed special channels in the bones of the cranial floor, which provide breathing while eating in a different way than in modern animals.
The last, smallest family of deinocephals is estemenosuchus. These large (up to 4 m) herbivorous animals had small horns on their heads.
The next representative of the order of therapsids was the suborder anomodonts(4% of all Permian genera Fig. 2.7.19). They were small creatures from 20 cm to 1.2 m in length, herbivorous and insectivorous. Some of the representatives of this suborder lived in burrows. Some anomodonts had two large fangs on the upper jaw, which were used to dig out edible roots from the ground. Anomodonts are the first synapsids to have a secondary palate, although not the full length of a mammal. Unlike more primitive synapsids, anomodonts could chew food normally, many of them did it not with teeth, but with horny growths on the jaws, like in modern turtles. Some large anomodonts had small horns on their heads. Looking ahead, we note that anomodonts are the most primitive of the synapsids that survived until the end of the Permian period.
Rice. 2.7.19. The representative of the anomodont suborder is dicynodontia. Another order of synapsids was theriodonts (animal-toothed lizards). These animals had a normal set of teeth, like in mammals - incisors, canines and molars. In some theriodonts, fangs (and maybe other teeth) could change an unlimited number of times, it is a pity that mammals later lost this ability. Theriodonts include 8% of all Permian genera, the lion's share of them (5% of all Permian genera) are representatives of the Gorgonops suborder - the first attempt of evolution to create a saber-toothed tiger. Not all gorgonops had really saber-toothed fangs; in many gorgonops, fangs were not much larger than those common for large predators of the modern era. Gorgonops were the first creatures capable of running fast for short distances. At the end of the Permian, Gorgonops dominated all ecological niches of large land predators; the previously listed predators could not compete with them and quickly died out. The sizes of Gorgonops ranged from 1 to 4.3 m. Small Gorgonops are outwardly similar to modern wild dogs, which is not surprising - the ecological niche is the same. Most of the Gorgonopsians were first described by Russian paleontologists, which is reflected in their names: foreigners(in honor of A.A. Inostrantsev, the largest of all Gorgonopsians Fig. 2.7.14), vyatkogorgon(Fig. 2.7.20) and even orthodoxy.
Rice. 2.7.20. Vyatkogorgon. Another suborder theriodonts – therocephalians. Some therocephalians had a fully built secondary palate, but it was built differently than in mammals - from other bones of the skull. Unlike Gorgonopsians, therocephalians' limbs were widely spaced, which did not allow them to run fast. Some therocephalians, for example, euchambersia(Fig. 2.7.21) had poisonous teeth, like those of modern snakes.
Rice. 2.7.21. Euchambersia. In the late Permian, other types of animal-like reptiles arose, for example dicynodonts(Fig. 2.7.22). Some of these species were no larger than a rat, while others were as large as a cow. Mostly they lived on land, but some switched to an aquatic lifestyle. The teeth of dicynodonts sat in cells, however, most of them retained only a pair of large fangs for biting plants. In all likelihood, dicynodonts had tortoise-like beaks. Some had tusk-like fangs, possibly used to tear the soil in search of edible roots.
Toward the end of the Permian period, some groups of reptiles became warm-blooded. This meant that they could stay active longer and didn't have to warm up in the morning after a cold night. To maintain the required body temperature, they had to digest food faster in order to extract the right amount of thermal energy from it.
The last and most advanced suborder of theriodonts - cynodonts(Fig. 2.7.23) - direct ancestors of mammals. These warm-blooded animals were already completely covered in hair, they were almost mammals. Representatives of this suborder developed teeth of various purposes, as in modern mammals. Sharp chisel-shaped front teeth (incisors) served to capture and bite off food. Dagger-shaped fangs could tear prey to pieces, and with flat molars with many cutting edges, cynodonts chewed and ground food.
Rice. 2.7.22. The representative of dicynodonts is Lystrosaurus (Lystrosaurus) The skulls of cynodonts have changed: strong jaw muscles have appeared, which are necessary for chewing. The nostrils were separated from the mouth by a special plate-like structure - the palate, like in crocodiles. Therefore, cynodonts could breathe through their noses even when their mouths were full of food, which in turn allowed them to chew their food more thoroughly. Perhaps on both sides of the muzzle they had tiny pits from which whiskers grew. Scientists believe that to maintain the required body temperature, cynodonts developed a woolen cover. In general, they were very similar to mammals. There is even an opinion that the platypus and echidna are actually cynodonts that have survived to this day. In the Permian, cynodonts have only just emerged; only a few genera are known. They were small (up to 60 cm) creatures, insectivorous, predatory and fish-eating (like modern otters). These are our distant ancestors. However, at the very time when cynodonts began to spread across the planet, a new, much more formidable group of reptiles came to the fore - dinosaurs. In the face of such a terrible enemy, only a few species of small warm-blooded cynodonts could survive. And they survived because they led an active lifestyle even in the cold, that is, they got their food at night, when the huge dinosaurs were inactive. Most cynodonts died out at the end of the Permian, but some managed to survive until the beginning of the Triassic. Their descendants were destined to survive the era of dinosaurs and lay the foundation for a new, highly organized group of animals - mammals, the future rulers of the Earth.
Rice. 2.7.23. Cynodont. Not all therapsids fit well into the above scheme, there are transitional and exotic forms that are not clear how to classify, such as tetraceratopsians, phthinodry and camagorgons.
In general, the reptiles of different and the same Permian continents differed significantly from each other, which indicates the existence of different climatic zones.
The end of Perm was marked by grandiose cataclysms. Continents collided, new mountain ranges rose, the sea either advanced on land or retreated again, the climate changed frequently and dramatically. Ozone-depleting gases such as hydrogen sulfide and methane were released into the atmosphere in large quantities, which led to the almost complete destruction of the planet's ozone layer. Millions of animals and plants could not adapt to all these changes and disappeared from the face of the Earth. During this greatest extinction in the history of the planet, more than half of all animal families died. Species that lived in shallow water were especially affected. More than 90 percent of terrestrial and 70% of marine animals have completely died out, including more than half of all amphibian species and most of the ammonites. The ancient wrinkled corals also disappeared and were replaced by modern ones. reef-building corals. And finally, the final trilobite extinction.
Trying to explain such a large-scale extinction in the Permian period, scientists put forward many different hypotheses. Many animal species have lost their habitat due to the uplift of mountain ranges and the disappearance of seas, lakes and rivers. Some species could not survive the sudden changes in climate caused by continental drift. Some left the scene because of the competition between species, which was greatly intensified by the confluence of the continents.
Particularly large losses were suffered by animals that lived in fresh water and in the oceans. We can only speculate about the reasons for this. The drier the climate became, the more water evaporated from rivers and lakes, and as a result they became more saline. Today, significant salt deposits have been found in Permian rocks. It is possible that the salt content in the water has changed repeatedly, and many marine animals have not been able to adapt to such fluctuations.
If on the political map of the world Russia occupies a fair part of the land, then on the geological map it is represented only by Perm. But it is here that we have the most interesting deposits of this time with the most unusual fossil creatures. At the end of the Permian period, 251 million years ago, volcanic eruptions, unprecedented in the history of the Earth, covered half of Siberia and wiped out almost all life from the face of the planet. Over 80 percent of the species that inhabited the land and oceans have disappeared, and most of them have left no descendants. The catastrophe put an end to the entire Paleozoic - the era of ancient life.
The Scottish geologist Sir Roderick Impey Murchison, after working in the Urals, considered it his duty to call the last period of the Paleozoic era Permian.However, whether the animals suffocated after a giant eruption, swept them away from the impact of a meteorite, or extinction occurred naturally, scientists will figure it out for more than a dozen years. And in order to delve into all these vicissitudes of life and death, it is necessary to tie the events that have occurred to a certain scale. For the history of the Earth, this is the International Stratigraphic Scale, in the colors of which geological maps are painted. (The word "stratigraphic" simply means "layered"). In search of the best layered deposits accumulated at the end of the Paleozoic era, the famous Scottish geologist Sir Roderick Impey Murchison climbed into the distant Urals 170 years ago. As Sir Murchison had foreseen, in this part of the continent the desired deposits were filled with the remains of various organisms. Already in 1841, in a letter to the Moscow Society of Naturalists, the Scot said that he considered it his duty to call the last period of the Paleozoic era Permian - after the name of the ancient people mentioned in Russian chronicles of the 12th century. The word "Perm" probably comes from the Vepsian "peram" - "distant land". Coincidentally, the Perm Territory was developed, first of all, for the sake of extracting salt and copper, which had accumulated just during the Permian period. This is our last one. The world of the Permian period was both similar, and at the same time completely different from the modern one. Let's start with the fact that at that time it was possible to walk around all the land on foot without getting your feet wet. Set out on the road, for example, in Eastern Siberia and, having successively passed Europe, North America, South America, Africa, Antarctica and India, reach Australia. After all, by that time all these continents had converged into a single supercontinent - Pangea. It occupied the Western Hemisphere, and in the Eastern Hemisphere there was nothing but the ocean - Panthalassa. Due to this position of the continents and continental glaciation near the South Pole, the ocean level was very low, and marine sediments accumulated in few places. Therefore, in search of Permian fossils, Sir Murchison had to go to the very east of Europe, where there was at least something. Representative marine layers of that time were preserved only in Central Asia, China and the USA, but in the middle of the 19th century they did not know about it yet. Now, of the entire Permian stratigraphic scale, Russia has only its lower part - the Ural section. So far... “That's why geological sections like those we see along the Chekarda and Sylva rivers acquire such importance: they quite fully represent the lower part of the Permian system,” explains paleobotanist Sergei Naugolnykh, an employee of the Geological Institute of the Russian Academy of Sciences. - Here the entire herbarium of the Permian period can be collected. Here are the giant relatives of modern horsetails and club mosses, here are the seed ferns - now there are none - and these are the oldest conifers, ”he takes out prints of leaves of various shapes and sizes from numerous boxes and boxes. Indeed, a herbarium. And he also has a whole collection of insects: mayflies, cockroaches and a great many forms that have not survived to this day. Only leaves and wings of insects on the stones were spread not by human hands, but by time itself - 270 million years have passed since then. Probably, the rich coastal forests of the Urals softened the harsh climate of the Permian period. Indeed, according to computer models, in a significant part of Pangea, the air was dry, and the average annual temperature drops reached 85 ° C even in the equatorial zone. So, only in a few regions - at the junction of South Africa and South America, in the middle part of North America and in the Urals - there were oases of terrestrial life with a variety of reptiles. Ancient Permians. They were small archosaurs - the ancestors of the future rulers of the land of dinosaurs, animal-like lizards that gave rise to mammals, and pareiasaurs, or cheeky lizards, a bit like giant turtles without a shell. Previously, reconstructions depicted how these giants roam among the endless dunes. It's not clear why, though. After all, there is no food there. However, Doctor of Biological Sciences Mikhail Ivakhnenko from the Paleontological Institute of the Russian Academy of Sciences drew attention to the structural features of the skeleton and skin of these pangolins: both of them were more suitable for semi-aquatic and even aquatic animals. Indeed, there were enough warm lagoons, lakes and river deltas in the Urals, where a sea the size of the modern Baltic Sea invaded from the north. In terms of lifestyle, Permian reptiles were more like amphibians. It is possible that hair (in combination with sweat glands), which animal-like lizards already had, appeared to protect against desiccation, and not from cold. The inhabitants of the Permian Sea also differed in a fair amount of originality. For example, huge helicoprion sharks with a toothy jaw curled into a spiral swam in it. If one of the modern sharks is called a sawfish due to the resemblance of its snout to a well-known carpentry tool, then Helicoprion could be called a "buzz saw fish". Recently, ichthyologist Victor Springer from the Smithsonian Museum of Natural History (Washington) had to rack his brains over the appearance of this monster. When he was working on a new exposure and trying to reconstruct a plausible helicoprion, he realized that this tooth spiral could not stick out. Then the teeth would show noticeable signs of wear, like the teeth of any other shark. There is no such damage. The ichthyologist guessed that the dental apparatus was deep in the throat, which means it was an overgrowth of gill cartilage. True, he did not answer the question of how the fish hunted. Why did all these unusual animals disappear? It is quite possible that in the course of evolution there come critical moments when a new global ecosystem is preparing to replace the previous one, and then even volcanoes and meteorites take on the role of a trigger mechanism. To understand what follows from what and after what, such detailed geological sections are needed, as in the Perm Territory.
On the territory of the former Perm Governorate. Now this tectonic structure is called Cis-Ural marginal foredeep. Murchison also discovered its wide distribution in the Urals and the Russian Plain.
This is the only geological system that has received a Russian name.
Permian divisions (systems)
| system | the Department | tier | Age, million years ago |
|
|---|---|---|---|---|
| Triassic | Lower | Indian | smaller | |
| Permian | Lopinsky | changxing | 254,14-251,9 | |
| Vuchapinsky | 259,1-254,14 | |||
| Guadalupe | Keptenian | 265,1-259,1 | ||
| wordish | 268,8-265,1 | |||
| Roadsky | 272,95-268,8 | |||
| Priuralsky | Kungur | 283,5-272,95 | ||
| Artinsky | 290,1-283,5 | |||
| Sakmara | 295,0-290,1 | |||
| Assel | 298,9-295,0 | |||
| Carbon | Upper | Gzhel | more | |
| The division is given in accordance with IUGS as of December 2016 | ||||
In accordance with the general stratigraphic scale adopted at a conference in Kazan in 2004, Russian geologists distinguish in the Permian system three department: lower (Ural), middle (biarmy) and upper (Tatar). The composition of the lower (Ural) section included the following tiers (from bottom to top): Assel, Sakmara, Artin, Kungur, Ufa. The middle (biarmian) division included the Kazanian and Urzhumian stages, and the upper (Tatar) division included the Severodvinsk and Vyatka stages. It is also proposed to distinguish between the Urzhum and Severodvinsk stages a separate Yurpalian stage and the Vyaznikovian stage above the Vyatka stage.
Flora and fauna of the Permian period
Insects
Of the insects in the Permian, there were beetles, which first appeared in this period - 270 million years ago (all or almost all belonged to the suborder archostemata) and lacewings (all species passed into the Triassic). Caddisflies and scorpions appear. In the Late Permian, there were 11 families of the latter, but only 4 passed into the Triassic. A single family of caddisflies passes into the Triassic.
Climate
The climate of the Permian period was characterized by pronounced zoning and increasing aridity. In general, we can say that it was close to modern. If anything, it had more of a resemblance to the modern climate than did subsequent periods of the Mesozoic.
In the Permian period, a zone of humid tropical climate is clearly distinguished, within which there was a vast ocean - Tethys. To the north of it there was a belt of hot and dry climate, which corresponds to the wide development of salt-bearing and red-colored deposits. To the north, there was a moderate zone of significant humidity with intensive coal accumulation. The southern temperate zone is fixed by the Gondwana coal-bearing deposits.
At the beginning of the period, glaciation continued, which began in the Carboniferous. It was developed on the southern continents.
The Permian is characterized by red-colored continental deposits and deposits of salt-bearing lagoons, which reflects the increased aridity of the climate: Permian is characterized by the most extensive deserts in the history of the planet: sands even covered the territory of Siberia.
Paleogeography and tectonics
Permian deposits in Russia
One of the most famous sites of fossil remains of the Permian period is Chekarda. In this Cis-Ural locality on the left bank of the Sylva River, deposits of the Koshelev Formation, belonging to the Upper Permian, were exposed.
Another location of the Permian fauna is the unique Kotelnichskoye near the cities of Kotelnich and Sovetsk, Kirov Region.
In addition, many Permian fossils have been found within the Arkhangelsk Oblast, especially near the Malaya Severnaya Dvina and Mezen rivers. Among the animals found there are such well-known ones as scutosaurus, foreigner, early cynodont
