Ankylosaurs. Family: Stegosauridae = Stegosaurs A story about a stegosaurus aquatic dinosaur 30m

(155-145 million years ago), lived in the western United States (approximately the states of Wyoming and Colorado).

These dinosaurs were herbivores, walked on 4 legs, and had spines and bone plates on their tail and back.

What did they eat and what kind of lifestyle did they lead?

Details about the body structure

This dinosaur had excellent protection; there were hard bone growths all over its body, which perfectly protected its throat, legs and torso.

On the back there are plates of different sizes arranged in 2 rows; the largest plates grew up to 1 m. They were not particularly durable and were used more for intimidation than protection. When an enemy appeared, the plates turned red (the color of danger), which scared away predators and also helped them compete for females with other males of the species. In addition, the back plates were a thermostat that accumulated heat and removed its excess.

But on the tail there were very sharp spikes, making a blow with the tail could stun his attacker and even kill him. The number of such spikes could be up to 4 pieces, and their length was from 70 cm to 1 meter.

Dimensions

The height of the stegosaurus was no more than 4 m
Body weight – 5-7 tons

Stegosaurus head

Limbs

Video No. 2.

Video No. 3.

Photos and pictures

The name "stegosaurus" means "lizard under the roof." The first researchers thought that its dorsal plates were arranged like tiles on a roof: obliquely and slightly overlapping. Subsequently, paleontologists hypothesized that they were located vertically in two rows, and this position was more likely to correspond to their function: to regulate body temperature.

The largest, but at the same time peaceful dinosaur was the stegosaurus. Stegosaurs had one very interesting feature in the structure of the ridge - there were two rows of triangular plates on it. Most likely, these plates served to protect against enemies and to regulate body temperature: under the sun's rays they accumulated heat, but if the body temperature became too high, then a light wind or shade was enough - and the same plates began to give off this heat.

What did a stegosaurus look like?

Stegosaurs were truly huge, they could reach 9 meters in length, and stegosaurs had long spikes on their tails (about a meter), with which they could defend themselves from predators.
Stegosaurus was a herbivore, for this reason its teeth were weak and could only chew plant food. The head was small in comparison with the massive body.

A unique genus, recognizable by scientists even from a distance. Why? – accepted Latin name. But it comes from two Greek words: roof (stegos) - lizard (sauros). The animal received it thanks to the main distinctive feature– the presence of a number of large leaf-shaped plates on the back. The small head contrasts especially against the background of the large body.

Business card

Time and place of existence

The drawing by Zdenek Burian shows one of the reconstructions in the habitat. There are clear tracks in the wet soil that could have been used by predators such as Allosaurus or Ceratosaurus to detect stegosaurids.

Types and history of discovery

Body structure

There was a whole series of plates on the back. The discoverer of the skeleton, G. Marsh, mistakenly assumed that they were connected to each other like tiles covering the back. However, it is now known that they were located perpendicular to the body of the animal. Precisely two parallel rows at some distance from each other in such a way that the sheet of one row was opposite the gap of the other. There was also a gap between the “leaves” of the stegosaurus. Really handsome - nothing to say.

The purpose of the plates is still unknown exactly. Discoverers first theorized that the plates protected it from attacks predatory dinosaurs. However, a detailed study of them scientific community in 1970 showed that they were fragile and did not pose any physical danger. And the attackers could easily hit the side of the body. Thus, now there are three options left: defensive and two peaceful.

The first suggests that the plates were painted in bright colors (and perhaps the entire stegosaurus). Presented in such a spiky, painted form near a predator, it could scare away or at least puzzle the offender. If the latter happened, then the tail came to the rescue, with which it was possible to deliver a targeted blow.

The second option is that each plate is pierced with large blood vessels. This design circulatory system made it possible to cool the body in case of extreme heat and, conversely, to quickly accumulate heat on cold mornings. After all, the stegosaurus was a cold-blooded reptile.

The third case is that the shape and color of the plates may have played a significant role in building relationships in a group of animals. Moreover, they could be used by males in mating games. There is also an assumption by Robert Becker that stegosaurs could even move bone decorations up and down. These nine-meter-tall peacocks, moving their plates and filling them with blood, more than compensate for grace with assertiveness. In fact, all three assumptions could be true - it was a universal tool.

Separately, it is worth mentioning the tail. At the end of it were attached sharp spikes, which, unlike plates, could cause significant damage to an unwary predator. The blow of the powerful tail could stun and even leave a mortal wound.

Stegosaurus skeleton

A close-up view of the skull of the same species.

Nutrition and lifestyle

Is a symbol American state Colorado, where it was first excavated in the 19th century by pioneers of paleontology.

Video

A unique genus, recognizable by scientists even from a distance. Why? - the accepted Latin name. But it comes from two Greek words: roof (stegos) - lizard (sauros). The animal received this thanks to its main distinguishing feature - the presence of a number of large leaf-shaped plates on its back. The small head contrasts especially against the background of the large body.

Time and place of existence

They lived at the end of the Jurassic period about 155.7 - 145.5 million years ago. All species are found in the western United States (Colorado and Wyoming).

At that time, the prevailing temperature there was warm, almost tropical climate- ideal for those herbivorous dinosaurs like a stegosaurus. The vegetation that grew on the continent, at first glance, resembled modern a tropical forest, however, today's plant species did not yet exist at that time. So, there were no flowering plants. Everywhere, next to the ferns and coniferous trees, ancient palm trees grew, which in appearance resembled modern ones.

The drawing by Zdenek Burian shows one of the reconstructions in the habitat. There are clear tracks in the wet soil that could have been used by predators such as Allosaurus or Ceratosaurus to detect stegosaurids.

INTERESTING INFORMATION. DID YOU KNOW THAT...

• IN Western Europe The fossilized remains of a relative of the stegosaurus were found.
• Obviously, stegosaurs lived for a short time in the Jurassic period. The remains of these dinosaurs are found only in upper layers rocks.
• Some modern reptiles his appearance resemble smaller copies of extinct dinosaurs.
• The lizard, which lives in Africa, has spines on its head and body, similar to those on the stegosaurus. However, this lizard is 60 times smaller than a stegosaurus, and its length reaches only 60 cm.

Types and history of discovery

There are currently three generally accepted species of stegosaurs. The rest either did not find sufficient evidence or were included in the main ones. Stegosaurus armatus was described by the famous professor G. Marsh back in 1877. These were also one of the first officially found remains of dinosaurs in general. They were excavated north of the small American town of Morrison. Stegosaurus stenops And Stegosaurus longispinus were smaller in size.

Body structure

The body length of this creature reached 9 meters (comparative dimensions are shown in the figure). The height is up to 4 m. The representative weighed 4.5 tons.

There was a whole series of plates on the back. The discoverer of the skeleton, G. Marsh, mistakenly assumed that they were connected to each other like tiles covering the back. However, it is now known that they were located perpendicular to the body of the animal. Precisely two parallel rows at some distance from each other in such a way that the sheet of one row was opposite the gap of the other. There was also a gap between the “leaves” of the stegosaurus. Really handsome - nothing to say.

The purpose of the plates is still unknown exactly. The discoverers first theorized that the plates protected it from attacks by predatory dinosaurs. However, a detailed study of them by the scientific community in 1970 showed that they were fragile and did not pose any physical danger. And the attackers could easily hit the side of the body. Thus, now there are three options left: defensive and two peaceful.

The first suggests that the plates were painted in bright colors (and perhaps the entire stegosaurus). Presented in such a spiky, painted form near a predator, it could scare away or at least puzzle the offender. If the latter happened, then the tail came to the rescue, with which it was possible to deliver a targeted blow.

The second option is that each plate is pierced with large blood vessels. This design of the circulatory system made it possible to cool the body in case of extreme heat and, conversely, to quickly accumulate heat on cold mornings. After all, the stegosaurus was a cold-blooded reptile.

The third case is that the shape and color of the plates may have played a significant role in building relationships in a group of animals. Moreover, they could be used by males in mating games. There is also an assumption by Robert Becker that stegosaurs could even move bone decorations up and down. These nine-meter-tall peacocks, moving their plates and filling them with blood, more than compensate for grace with assertiveness. In fact, all three assumptions could be true - it was a universal tool.

Separately, it is worth mentioning the tail. At the end of it were attached sharp spikes, which, unlike plates, could cause significant damage to an unwary predator. The blow of the powerful tail could stun and even leave a mortal wound.

Stegosaurus skeleton

The photo shows museum exhibits of the species Stegosaurus stenops.

A close-up view of the skull of the same species.

The head was small, especially considering the huge body of the dinosaur. The skull did not exceed 40 cm in length.
The brain was also not very large - the size of a walnut.
Due to underdeveloped jaws, only tender leaves had to be eaten.

Purpose of plates and tail spikes

It is still not clear exactly why these ancient ornithischians needed plates. The theory put forward in early times, that Stegosaurus plates served as protection when attacked from above, did not stand up to criticism, since the horny plates were very fragile and did not in any way resemble defensive shields. It was not difficult for predators such as allosaurs to chew them, not to mention tyrannosaurs and other giant predatory theropods. In addition, in a collision with them, no special damage could be caused, since they were sometimes so blunt that they not only could not pierce the cellular, rough skin of predators, but, on the contrary, from strong blow they themselves could have been injured.

Some have suggested that predators, due to their narrow-mindedness, like real dogs, bite their teeth into everything that sticks out and into everything that is convenient to grab onto. The dorsal plates of stegosaurs had these same features. While allosaurus and other predators ruffled their plates, the animal itself, spreading its limbs wide, defended itself with its spike-shaped tail, and after defeating one or several aggressive individuals, the predators allegedly simply retreated without causing any significant damage to the stegosaurus.

Another assumption of scientists is based on the fact that stegosaurs needed plates for thermoregulation. It is possible that these porous horny formations could be completely saturated with a dense network of small blood vessels, and thus were excellent for cooling the body in extreme heat based on the principle of elephant or hare ears.

Excavations indicate that stegosaurs could defend themselves quite effectively and deliver lethal blows with their powerful spiked tail. A considerable number of the same allosaurs with holes in the body have already been found, one to one matching the size and other parameters of the tail spines of stegosaurs.

Nutrition and lifestyle

Stegosaurs cut down low vegetation with teeth adapted to this. However, there are suggestions that grass and shrubs were not the only food. The dinosaur's hind limbs were much larger than its front ones, so it is possible that it could stand on them (for a short time) to pluck the lower branches of trees.

It is a symbol of the American state of Colorado, where it was first excavated in the 19th century by pioneers of paleontology.

In culture

• Stegosaurus appeared in the film Jurassic Park 2: lost World", then there was a small scene with a stegosaurus on background in Jurassic Park 3.
• IN computer game"ParaWorld" stegosaurus either wanders through lava-scorched glades and savannas, or transports people and weapons. Also found in the game Jurassic Park: Operation Genesis.
• Stegosaurus participates in documentaries BBC Walking with Dinosaurs (Time of the Titans episode) and The Ballad of Big Al.
• Several stegosaurs are depicted in the Jurassic segment of Discovery's When Dinosaurs Roamed America. One of them digs a hole during a drought, trying to get to the aquifer; a couple of others are attacked by a ceratosaurus. Having fought off the predator with the help of his spiked tail, the male shows the female his brightly colored dorsal plates, but she is not ready for mating. A few days later he repeats marriage ritual, this time successfully.
• Also, the most modern and colorful depiction of a stegosaurus was obtained in “Jurassic Fight Club” (“Lost Worlds”).
• Stegosaurus can be raised in Zoo Tycoon 2 Extinct Animals.
• Stegosaurus appears in Arthur Conan Doyle's The Lost World.
• Appears in the game "Jurassic World: The Game", where he is somewhat underestimated, as he loses to the Spinosaurus, although in reality he would be stronger than him. However, it is equal in strength to the Allosaurus, which corresponds to reality.

Video

Sources

http://dinosaurs.afly.ru/stegosauria/48-stegosaurus

Armored dinosaurs or ankylosaurs belong to the class of reptiles, the subclass of archosaurs and the order of ornithischian dinosaurs, which appeared on the planet during the Cretaceous period (the end of the Mesozoic era) approximately 145 million years ago.

The history of archaeological discoveries cannot boast of a large number of finds related to armored dinosaurs. Therefore, paleontologists do not have the opportunity to thoroughly study and trace the evolutionary development of ankylosaurs. To date, science knows only 30 species of these animals, the fossilized remains of which were discovered in the Cretaceous deposits of Asia, Europe, South and North America, in particular in Canada and the USA (Wyoming and Montana).

Classification of ankylosaurs

According to the generally accepted classification, belong to the group of ankylosaurs: Scelidosaurus, Nodosaurus, Acanthopholis, Polacanthus, Sauropelta, Paleoscincus, Panoplosaurus, Talarur, Euoplocephalus and the Ankylosaurus itself.

Rice. 1 - Ankylosaurs

Scelidosaurus was the first in the chain of armored dinosaurs. It arose 100 million years earlier than the ankylosaur, reached 3.5 m in length, and fed on palm-shaped cycads and ferns. The bony plates and spines of its shell formed 7 rows along the body, so the name of the ancestor of the ankylosaur translated from Latin means "dismembered lizard".

Nodosaur had a slender body, a narrow head, a loose, rather weak armored shield and a pointed tail. The nodosaur owes its name to the large nodes that covered the skin of the lizard.

Acanthopholis reached 5 m in length, had a sharp tip on the tail, and its shoulders and neck were dotted with rows of short spines.

Polacanthus had a similar structure and differed only in the size of the double-sided spines, which were twice as large as those of Acanthopholis.

The largest animal groups of ankylosaurs arose during the last period of their existence on Earth.

Sauropelta had strong solid armor and was particularly massive, as it weighed 3 tons and reached 7 m in length.

Paleoscincus, nicknamed "ancient lizard", And panoplosaurus, whose name stands for "lizard with a solid tail", lived on the planet at the end of the era of dinosaurs and were considered real giants.

Talarur reached 6 m in length, had a strong solid armored shield and a tail, the tip of which resembled a mace. The remains of a dinosaur discovered in Mongolia indicate that the thickness of the bony armor plates was 5 cm.

Euoplocephalus means "typical armored head". This large ten-meter ankylosaur could easily fend for itself thanks to its powerful tail. Its back part was made of ossified tendons, which turned the limb into a kind of rigid handle with a thickening at the end, which could be used to deliver dangerous targeted blows.

The most dangerous among the listed representatives of the group were themselves ankylosaurs from the suborder ornithischians, which were also called "tank reptiles". These were squat ten-meter armored dinosaurs with a wide head, a powerful body, reliably protected by strong armor, and a tail with a dangerous tip in the form of a mace.

Features of ankylosaur armor

Like modern animals whose bodies are covered with protective shells, many species of ankylosaurs had strong armor. As in the case of living turtles and crocodiles, the armored shield protected the dinosaurs from numerous enemies and other aggressive threats. external environment. This assumption was confirmed immediately as soon as scientists began researching the structure of several types of armor. However, they never expected that the structure of ancient armored shields would turn out to be much more interesting and more complex design armor of modern animals. Moreover, prehistoric shells could compete in strength with the latest achievements in the field of military technology.

The strongest solid armor- the most striking feature that distinguished the dinosaurs of the ankylosaur group from other species (Fig. 2). During experiments, paleontologists from the University of Bonn found that prehistoric layered armor protection was similar in strength to composite materials that are currently used by the military. The research results clearly demonstrated that some elements of ancient ankylosaur shells were as strong as modern bulletproof vests. In addition, some types of dinosaurs wore thinner and lighter plate armor, which was in no way inferior to the heavy shells of their relatives in terms of protective properties.

Rice. 2 - Ankylosaurus Armor

Invaluable contribution to study of ankylosaurs contributed by the German paleontologist Thorsten Scheier, who managed to finally debunk the myth of the analogy between the layered structure of bone plates and the structure of crocodile skin. According to the scientist, ankylosaur armor was much more complex than the primitive protective layer at the crocodile. It resembled chain mail, consisting of small plates, the number of which varied within several hundred thousand. Most of these plates were no larger than a European one-cent coin, but there were also ten-centimeter-long bone plates equipped with spikes on the reptile’s body. Unlike turtle shells, the individual plates were not fused together, but were packed tightly next to each other. This structure had high plastic properties, did not experience damage under strong pressure and did not break under strong impacts.

To conduct his research, the scientist used a powerful polarizing microscope. When examining the bone plates, the device showed that the fibers in them were woven like the joints of fibers in a durable mat. That is, within each layer, the fibers ran parallel to each other, and the upper and lower levels were located at an angle of 90 degrees relative to the adjacent layer. This design ensured high strength in all directions at different angles. This observation has led to the factory production of propeller blades and protective equipment from composite material using the same principle that was used to form the armor of the ancient ankylosaur. The only difference is that instead of organics, carbon fibers or fiberglass are taken.

Distinctive features of ankylosaurs

Unlike the stegosaurs of the Jurassic period, ankylosaurs were much better protected from predators. They were covered from head to paw with armor made of tightly fitting bony plates covered with durable corneal skin, which made ankylosaurs squat and slow animals. Tail and sides of ankylosaurs equipped with thorns, sharp growths and thorns. Some species had a kind of ossified thickening at the end of their powerful tail, with which they could defend themselves and their offspring from the attacks of numerous predators.

Rice. 3 - Skeletal structure of ankylosaurs

The most warlike and well-armed species are ankylosaurs - lizards from the suborder ornithischians, who lived about 70-65 million years ago during the late Cretaceous period. These large “armored” reptiles reached 6-10 m in length, 2 m in width and weighed about 5 tons. They were so well equipped that even their eyelids were covered with armored scales. The spindle-shaped bodies were protected by a mosaic formed from alternating rows of polygonal plates of different sizes. The legs of these reptiles had dangerous spines, and their maneuverable muscular tail was surrounded by armored rings of ossified skin with spines. Triangular ankylosaur head had two large horns curved back and was protected by a solid bone helmet 5 cm thick. Scientists suggest that, judging by the size of the skull, there was relatively little space left in the animal’s head for the brain.

Biography of ankylosaurs

Ankylosaurus was a herbivorous reptile that walked on four limbs. Its jaws were equipped with a small number of weak teeth suitable for grinding soft plant food. Unlike long-necked herbivores, this clumsy heavyweight could not rise on its hind legs. Therefore, the ankylosaur had to be content with coarse ground grass, the lower layer of vegetation, ferns, palm-like plants and cycads. The calorie content of such food was low, so the ankylosaur must have had a huge stomach size. This is evidenced by the impressive dimensions of the reptile’s body and the presence of an enzymatic system that ensures the digestion of fiber.

Rice. 4 - Shelled dinosaur

Life of armored dinosaurs occurred during a period of climate change after the Jurassic period. The displacement of continents from their previous positions led to the fact that the change of seasons throughout the year became more and more noticeable. The climate changed from continent to continent, causing differences in the surrounding flora. In turn, the rapid increase in plant biomass led to the development of new species of herbivorous reptiles - iguanodons, triceratops and pachycephalosaurs. However, the dominant position among terrestrial animals was occupied by predatory lizard-hipped dinosaurs, for which ankylosaurs served as game. They constantly had to defend themselves from attacks by tyrannosaurs, tarbosaurs, deinonychus and spinosaurs.

The most weakness ankylosaur- This is the abdominal cavity. If a predator managed to get to the dinosaur’s unprotected belly, in most cases it would no longer be able to survive. Therefore, when danger arose, the ankylosaur had two options for defense: to cling to the ground, scaring off opponents with a terrifying spiky shell, or to swing its tail with a heavy tip in the form of a mace, which, if successfully hit, the dinosaur could break the attackers’ bones.