• Class: Reptilia = Reptiles or Reptiles
  • Subclass: Archosauria = Archosaurs
  • Superorder: Dinosauria † Owen, 1842 = Dinosaurs
  • Order: Saurischia † Seeley, 1888 = Lizard-hipped dinosaurs
  • Family: Allosauridae † Marsh, 1879 = Allosaurids

Genus: Allosaurus † Marsh, 1877 = Allosaurus

Reconstruct appearance allosaurus for paleontologists was not large, since over 60 of its skeletons have already been found in America different sizes. In addition, scientists managed to find the remains of more than a hundred Allosaurus eggs in Portugal, and the bones of tiny cubs were also preserved, which allowed scientists to quite accurately imagine what it was like. initial period the life of these lizards.

Adults, the largest allosaurs, had a body length of up to 11-12 meters, while their weight ranged from 1 to 2 tons. Allosaurus had strong, large hind legs equipped with four toes. In this case, three fingers were turned forward, and one - back. This structure of the fingers helped the Allosaurus maintain a stable balance, standing on two legs, and also easily overtake any victim. His front legs were underdeveloped, although during the battle they, equipped with claws, also went into action. The massive tail of the Allosaurus helped to maintain balance both in a sitting position and while running when maneuvering.

The Allosaurus brain, according to paleontologists, was very similar in structure to the brain of a crocodile, although smaller. Characteristically, Alosaurs had superciliary ridges on their heads, which, most likely, contributed to maintaining the salt balance in the body. Although, according to some scientists, they were a kind of decoration, thanks to which the males of allosaurs attracted females to themselves. It is these crests that now allow scientists to easily distinguish an Allosaurus skull from a Tyrannosaurus rex skull.

Allosaurus were carnivorous dinosaurs and predatory image life. Their prey were various herbivorous dinosaurs, which is confirmed by the found piece of the tail of Apatosaurus, which preserved deep bite marks from the Allosaurus bite and its knocked out teeth. Giant jaws and sharp teeth allowed this lizard to deal even with large animals. They also attack predators. Voracious lizards swallowed food in huge chunks, they could swallow an animal the size of a man in one sitting.

Newborn allosaurs also had sharp teeth and were carnivorous. They, barely hatched from the egg, began to hunt for insects, and as they grew, the prey that they could master also increased.

According to some scientists, allosaurs were the most common dinosaurs. jurassic. In addition, the Allosaurus was one of the most aggressive and voracious dinosaurs. In addition to food, allosaurs were of little interest, so they did not disdain even carrion....

An interesting discovery was made by paleontologists in Cleveland Lloyd in the United States, described in the famous work "Dinosaur Career". There, in one place, 44 skeletons of allosaurs were found at once. As it was possible to establish, in those old times there was a swamp in this place. By its negligence, a giant brachiosaurus wandered into it and got stuck. This was not used by a whole flock of allosaurs, which rushed for easy prey. However, the swamp sucked in the Allosaurs one by one. Scientists still cannot explain this behavior of the dead allosaurs, and perhaps that is why the word "allosaurus" itself means "strange lizard".

Lower Tithonian, approximately 155-145 million years ago). Allosaurus were predators, moving on powerful hind legs, while the forelimbs were relatively small. Allosaurus reached an average of 8.5 meters in length and 3.5 meters in height. The remains of allosaurs are known from North America, South Europe and East Africa.

History of study

The first remains were studied and classified in 1877 by Othniel Charles Marsh. Along with Tyrannosaurus, Allosaurus is the most popular carnivorous dinosaur. He has appeared in many feature films, for example, "The Lost World" in 1925, or the film adaptation of R. Bradbury's story "And Thunder" in 2005. Allosaurs were most vividly and plausibly presented in the BBC series Walking with Dinosaurs and the film The Ballad of Big Ale.

Description

Allosaurus was a large, bipedal carnivore with a large skull equipped with dozens of large, sharp teeth. Representatives of the type species, Allosaurus fragilis, reached an average of 8.5 meters in length, 3.5 meters in height and weighed about a ton, although, based on larger fragmentary remains, it can be assumed that large individuals could reach up to 11 meters in length, about 4 meters in height and weighs about 2 tons. Allosaurus moved on large and powerful hind legs, while its forelimbs were relatively small, they had three large, curved claws. The massive skull was balanced by a long, heavy tail.

Kinds

While the exact number of actual species is unknown, but today the following stand out:

Allosaurus bones have been found in the Upper Jurassic of Australia, Africa, and North America (Wyoming, Utah, Colorado).

The famous "Big Al", by the way, may belong to an as yet undescribed species. The so-called "dwarf polar allosaurus" from the Lower Cretaceous (Albian) of Australia is known only from the ankle bone and cannot be assigned to the genus Allosaurus. African view Allosaurus tendagurensis may not belong to this genus, but certainly belongs to allosaurids. It is likely that at one time a large species of Allosaurus was one of the main predators and hunted herbivorous dinosaurs, which it could overpower. Large and strong dinosaurs such as sauropods and stegosaurs, allosaurs most likely attacked in concert. There is evidence (traces of different representatives of the same species in one place, mass graves of the remains of the same species) that allosaurs hunted in packs, but some paleontologists believe that they were too aggressive to live in packs.

Dimensions

Representatives of the most well-studied species A. fragilis on average reached 8.5 meters in length, the largest individuals are estimated at 9.7 meters and 2 tons of weight. In 1976, James Madsen studied a number of skeletons of different sizes and types and found that the maximum length large species reached 11 meters. Accurate weight Allosaurus (as well as all dinosaurs) is difficult to determine. But compared to giant theropods Cretaceous Allosaurus was a small lightweight.

The following table shows information about the weight of allosaurs, obtained in different ways:

Skeleton structure

Allosaurus had six cervical vertebrae, fourteen dorsal vertebrae, and five sacral vertebrae. The number of caudal vertebrae is unknown: J. Madsen believes that there were at least 50 of them, and Grigory Paul, that there were no more than 45. Allosaurus vertebrae had through holes. Birds have similar openings: they help push air out of the air sacs right through the skin, without wasting energy on exhaling from the throat; which is very convenient for large physical activity(for example, when flying). From this it follows that the Allosaurus, most likely, intensively pursued its prey - otherwise it is difficult to explain the presence of such a method of breathing in it. It is possible that Allosaurus had additional ribs, like Tyrannosaurus Rex, but these are possibly fragments of bones or a heavily fossilized thymus bone, the presence of which in Allosaurus was proved in 1996. In some allosaurian specimens, the ends of the pubic bones are not connected; perhaps it helped them to lie on the ground; James Madson believes that this helped the females lay eggs and was sexually dimorphic.

The structure of the limbs

The front paws of the Allosaurus were relatively short compared to the hind legs (in adults, only about 35% of the length of the hind limbs), they had three fingers, which ended in large, strongly curved claws. The forearms were somewhat shorter than the shoulders (the ratio of the length of the humerus to the ulna was approximately 1:1.2); the wrist was equal in length to the ulna. Of the three fingers on the front paw, the middle one was the largest and differed from the others in the number of phalanges. Allosaurus legs were adapted not so much for speed of movement as for stability. On the foot of the Allosaurus there were three supporting fingers, and one that was not used when walking. There are also indications that the Allosaurus had a fifth vestigial toe on its hind foot.

The structure of the skull

The skull of the Allosaurus, compared with the skulls of other theropods, was small. For example, the skull of Tarbosaurus was twice as large. Paleontologist G.S. Paul, having studied all the known skulls, came to the conclusion that the largest reached "only" 845 mm. Each premaxilla had five D-shaped teeth, and each upper jaw had fourteen to seventeen teeth, depending on the species. On each lower jaw, there were from fourteen to seventeen teeth, most often found skulls with sixteen teeth on the lower jaw. The teeth became shorter, narrower and more curved towards the back of the skull. All teeth had sawtooth edges and were easily replaced after falling out.

The well-developed hinge joint between the jaws was strongly displaced towards the back of the skull, which gave the Allosaurus the ability to open its mouth very wide. In addition, there was another articulation in the middle of the lower jaw that increased this possibility.

The skull had paired crests, which gradually turned into horns. These horns were enlarged brow ridges, which are different for all allosaurs. On top of the bone base of these growths, there was probably a layer of keratin coating. Perhaps these combs were intended to protect the eyes from bright sunlight. It was previously thought that allosaurs butted them, but this hypothesis is now rejected, as these horns are too fragile for such a purpose. Inside the horns, a salt gland could also be located.

The air passages of Allosaurus were more developed than those of more primitive theropods such as Ceratosaurus and Marshosaurus, due to which Allosaurus had a very well developed sense of smell, and possibly also had a vomeronasal organ. The frontal bones of the skull were thin, possibly to improve the thermoregulation of the brain.

Systematics

Allosaurids belong to the allosaurid family of the superfamily Allosauroids. The allosaurid family was proposed in 1878 by Othniel Charles Marsh, but the term was not used until the 1970s, and allosauroids and carnosaurs were placed in the same family of megalosaurids.

After the publication of Madsen's writings on allosaurs, the term "allosaurids" began to be used by many paleontologists. As studies show, members of the allosaurid family were usually larger than megalosaurids. Very close to allosaurids are dinosaurs such as the Indosaurus, Pyatnitskisaurus, Piveteausaurus, Yangchuanosaurus , Acrocanthosaurus , Chilantaisaurus, Compsosuchus, Stokesosaurus And Szechuanosaurus.

Allosaurids were one of the families of the superfamily Allosauroids, which also includes carcharodontosaurids and synraptorids. Previously, it was allosauroids that were considered the ancestors of tyrannosaurids, but now it has been established that this is not the case.

History of study

Due to the "bone wars" between Marsh and Kuop in the 1880s, confusion arose in the names of species and genera. The first fossils were described by the geologist Ferdinand Vandiver Heiden in 1869. Hayden was given the remains by Colorado farmers who found them in the Morrison Formations. Hayden sent the samples to Joseph Leidy, who took them for the remains of the already known European dinosaur poekilopleron at that time. Subsequently, Leidy decided that these remains deserve to be assigned to a separate genus - antrodomeus.

The first fossils of the type species were found in the Upper Jurassic of the Morrison Formation. Othniel Charles Marsh described the type species A. fragilis in 1877 on the basis of partially preserved three vertebrae, fragments of ribs, teeth, leg bones and humerus. The very name Allosaurus, which means "strange lizard", was given due to the fact that its vertebrae were very different from those of other dinosaurs known at that time. Type species name fragilis meaning fragile or brittle, was given because of the fragile structure of the vertebrae. Edward Cope and Charles Marsh, being in scientific competition, did not have time to compare their new findings with the old ones. Because of this, some fossils that are now classified as species or subspecies of Allosaurus have been separated into separate genera. These pseudogenera include Creosaurus, Labrosaurus And Epanterias.

After the discovery and description of the Allosaurus holotype in Colorado, Marsh concentrated his work in Wyoming, then, in 1883, he worked again in Colorado, where Deputy Flesh found an almost complete Allosaurus skeleton and several partial ones. In 1879, one of Cope's assistants found a specimen in the Como Bluff region of Wyoming, but apparently Cope was unable to excavate these specimens due to their huge amount. When these specimens were excavated in 1903 (a few years after Cope's death), they were found to be among the most complete therapod remains. It also turned out that in Como Bluff, next to the skeleton of an allosaurus, lies the skeleton of an apatosaurus. Other theropod fossils have also been found at Como Bluff, but they have not yet been described.

The title confusion is exacerbated by the brevity of the descriptions left by Marsh and Cope. In 1901, Samuel Wendel Williston suggested that it was wrong to single out Creosaurus And epanterias into separate genus from Allosaurus. As evidence, Williston pointed out that Marsh had never been able to distinguish an Allosaurus from Creosaurus. The earliest attempt to understand the situation was made by Charles W. Gilmour in 1920. He came to the conclusion that the caudal vertebrae are identified as belonging to antrodomeus are no different from the same Allosaurus vertebrae. Thus, the early name should be preferred, as they take precedence. Since then the title antrodomeus was used for the name of this genus for more than fifty years, until James Madsen examined the remains found at Cleveland Lloyd and concluded that the name Allosaurus should be used because antrodemus was described on too scarce material.

Niramin - May 31st, 2016

Allosaurus is an extinct dinosaur that lived in the territories North America, East Africa And southern Europe about 145 million years ago.

Adult males could reach a weight of 2 tons, a height of 4 meters and a length of 11 meters. They looked particularly menacing. The massive head, up to 90 cm long, was located on a powerful S-shaped neck. There were growths above the eyes, superciliary ridges, according to some paleontologists, they served to protect the eyes from light, but there is also a version that they were an ornament to attract females. The hinge joint of the jaw was located so that the mouth opened very wide, in the mouth there were very sharp teeth 10 cm long. The sawtooth edges of the teeth were bent inward, which made their bite incredibly tenacious.

Allosaurs walked on powerful hind limbs. The front legs were shorter and also very strong. The hind legs were four-fingered, and the front ones were three-toed and armed with sharp claws, which helped to grab the victim during an attack. With the help of a heavy, powerful tail, they maintained balance when moving.

Carnivorous allosaurs hunted alone, but they could form packs to attack giant lizards such as brachiosaurs.

The confrontation between the tyrannosaurs, which lived about 65 million years ago, and the allosaurs would be very interesting. Tyrannosaurs were heavier and bigger, but they were also somewhat clumsy. The short weak limbs of tyrannosaurs posed no threat when allosaurs would have opposed power, strength and the ability to hunt and pursue prey.

Below is interesting pictures, Photo and video.













Video: Allosaurus skeleton.

Video: Allosaurus Trap

Video: Allosaurus - Planet Dinosaur - Episode 4 - BBC One

Video: Tyrannosaurus Rex vs Allosaurus || Stop motion Dinosaurs

Video: T-Rex vs. Allosaurus | Jurassic World Dinosaur Fight

In the United States, he is especially popular, which is why he has been repeatedly included in the list of the main characters of documentaries. Latin name Allosaurus comes from the Greek words - another lizard. For what reason? The fact is that at the time of the description of the genus in 1877, the specimen found was significantly different from the few early fossils of "terrible reptiles". It is an important link in the study of the evolution of the latter.

Business card

Time and place of existence

Allosaurs existed at the end of the Jurassic period, about 155 - 150 million years ago (Kimmeridgian and the beginning of the Tithonian stages). They were distributed in the territory of the modern USA and Portugal.

Realistic 3D rendering of a theropod by the hands of Vlad Konstantinov.

Types and history of discovery

The only species currently recognized is Allosaurus fragilis, respectively, which is typical.

The history of the finds is confusing, because it is replete with numerous names of the same species. However, we will try to unfold this tangle in chronological order.

The first Allosaurus fossil was found in 1869 at Middle Park near Granby, Colorado, USA. locals described them as petrified horse hooves. They were purchased from miners and described by the geologist Ferdinand Vandiver Heiden.

The scientist then sent the specimen to University of Pennsylvania anatomy professor Joseph Leidy, who identified it as half of a dinosaur's tail vertebra. Previously, he assigned the individual to the already known European theropod genus Pekiloppleuron, giving the name Poicilopleuron valens (the correct name of the genus Poekilopleuron, but then several spellings in Latin were used). Later, he transferred it to a separate genus - antrodemus. However, it is now clear that these were the primary remains of a representative of allosaurs.

The official name and Full description was given by Charles Masch in 1877 on the basis of a YPM 1930 specimen found by his assistant Benjamin Mudgee in the now famous Morrison Formation, more specifically in the Garden Park area of ​​north Canyon City, Colorado, USA.

We deciphered the name of the genus at the beginning of the article, and the species fragilis means "fragile". This is due to the lightweight structure of the predator's vertebrae.

This represents an allosaurus prowling in a swampy area, Todd Marshall.

body structure

The body length of the Allosaurus reached 9.7 meters. The height is up to 2.8 meters. He weighed up to 2.3 tons.


Comparison of several individuals of Allosaurus and humans. Stephen O'Connor (England) did the hard work.

We rely on the confirmed length of the largest complete specimen. He moved on two powerful legs. The foot, as usual, consisted of a trinity of support fingers and a small rear one. Unlike Tyrannosaurus Rex, Allosaurus had sufficiently developed forelimbs capable of inflicting damage on herbivorous dinosaurs in a close encounter. The brush consisted of three fingers, each of which was equipped with a sharp claw. They also served as additional manipulators when cutting carrion.

Although the skull of the Allosaurus is similar in in general terms on ceratosaurus, but was more durable and massive while maintaining mobility (see exhibits below).

Allosaurus skeleton

The photo shows an exhibit of the Allosaurus fragilis species, installed in the lobby of the San Diego Museum of Natural History (USA).

Below is a skull from the collection of the Sedgwick Museum of Earth Sciences (Cambridge, England).

We also offer a graphical reconstruction of Allosaurus fragilis by paleoillustrator Scott Hartman.

Nutrition and lifestyle

Despite the fact that the fertile environment of Late Jurassic America contributed to the emergence of a host of predators of various sizes, the Allosaurus confidently occupied the top step. the food chain. Even the formidable ceratosaurus could not compete with him.

Who was usually hunted? It is known for certain that in addition to small herbivorous dinosaurs, allosaurs could also choose large sauropods - apatosaurs as targets. Of course, it would be reckless to attack such giants alone or even in pairs, therefore, despite their solid size, allosaurs had to unite in well-coordinated groups consisting of a dozen individuals. Having attacked the trail and coolly tracked down the giants, they tried to attack a sick or young individual, having previously cut it off from the main herd. The hungry Allosaurus did not disdain carrion.

As proof of these facts, tail vertebrae of Apatosaurus were found with scratches and holes, the distance between which was identical to the gaps of the Allosaurus teeth, the remains of which were found nearby. The victim could simply die from the disease, then a predatory lizard stumbled upon him. Larger versions are also possible: he was first hunted down together with a group of relatives, or a detachment of ceratosaurus did the same. In the latter case, the allosaurus that arrived in time was quite capable of frightening and dispersing smaller theropods, thereby winning back the desired prey.

Video

Excerpt from documentary film"Planet of the Dinosaurs". Allosaurus is shown here as a skilled hunter, able not only to sneak slowly, but also to use any features of the landscape when tracking down a grazing Camptosaurus. A special method of attack is proposed, where the maximum opening is first performed, and then a sharp compression of the jaws, creating the effect of "garden scissors".

Fragment of the documentary film "Walking with Dinosaurs". You will be able to see the care for the offspring and the cubs themselves.

Dinosaur Allosaurus is bright representative predatory theropods that lived on our planet in the Jurassic period, and this is 155-145 million years ago. Literally from Greek, allosaurus is translated as a strange, different lizard, and for the first time its remains were found and studied back in 1877.

Allosaurus dinosaur appearance

Allosaurus was pretty large predator. Its large and weighty skull was equipped with dozens of powerful and sharp teeth.

This dinosaur moved exclusively on two powerful hind legs, as for the front ones, they were poorly developed and the only thing that was remarkable about them was three curved claws.

Tail large sizes helped the Allosaurus to balance the rather large front part and also helped with movement and maneuvers, and in the normal state, it may have helped the Allosaurus to sit.


As for the sizes, they could fluctuate within the same species. So it is known that a typical representative of allosaurs was up to 9 m long, and up to 4 m high, and at the same time could weigh about a ton. But it is also known that, which could reach 11 m in length and weighed about 2 tons.

The brain of this dinosaur in its structure and size was very similar to the brain of a crocodile. The skull itself was equipped with superciliary ridges, which, according to scientists, could serve as an ornament, thereby attracting the opposite sex.


Allosaurus lifestyle

Allosaurs ate exclusively food of animal origin and led a predatory lifestyle. It is safe to say that in their Jurassic era they had no equal, and they were quite bright and typical representatives of dinosaurs, which could not but affect the formation of the image of the Allosaurus as such.

It is this species that is so colorfully described both in S. Spielberg's "Jurassic Park" and in " Lost world» A. K. Doyle.


Allosaurs were very voracious, which they successfully compensated for with their indiscriminateness, attacking not only any Living being, but not shunning carrion. According to the researchers, they quickly dealt with their prey, literally tearing it apart with their numerous and sharp teeth. At the same time, they could swallow prey in one sitting, corresponding in size to the size of a person.

Only after hatching from the egg, allosaurs, like true predators, began to conduct their first hunt. And even if at first it was insects, then birds ... the prey grew, as the Allosaurus itself grew up.