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Allosaurus

Allosaurus is a class of carnivorous, upright-legged dinosaurs that lived in the Jurassic period, 155 to 145 million years ago. The name Allosaurus means “distinguished lizard.” What is meant by the name is that the shape of its concave vertebrae was distinct (when it was discovered) from the rest of the known dinosaurs. σαῦρος) means lizard. The first fossil of this dinosaur was discovered in the year 1877 as a result of Othniel Charles Marsh's excavations in the United States of America, and it quickly attracted the interest of many ancient biologists and was one of the first carnivorous dinosaurs that scientists studied thoroughly.

Allosaurus was a large predatory animal that walked on two legs, with an average length of 9.5 meters, and in some cases it may have exceeded 12 meters. Allosaurus was distinguished by a huge skull, and it had dozens of teeth with serrated ends to help it cut food. It had three fingers in its hands, which are small compared to its huge, strong legs, and its tail was muscular and heavy to help balance the body. Allosaurus is classified in the family Allosaurus, which in turn is a class of carnosaurian carnivorous dinosaurs. Scientists faced various problems in classifying Allosaurus' relatives, as they did not limit it to a clear number of species. Most of the known Allosaurus fossils have been found in the Morrison Formation in North America, and some have been found in Portugal and possibly Tanzania.

More Allosaurus fossils than any other large predator in the Morrison Formation have been discovered, which indicates that it was at the top of the food chain in its ecosystem, and perhaps its prey were large herbivorous dinosaurs, perhaps even other carnivorous dinosaurs, and it is possible that it hunted game from the ornithopod species Stegosauria and sauropods. Some researchers think that Allosaurus lived a social life with its own kind and that it hunted in groups, but others think that it was a hostile animal that preferred a lonely life, and that the evidence of collective hunting was discovered by carcasses that were fed by single animals instead of a cooperating flock of Allosaurus.


the description

Allosaurs were large, carnivorous dinosaurs with a massive skull, short neck, and long tail, although they had short legs and arms. The average length of Allosaurus was estimated at 8.5 meters, and the largest fossil discovered of it (MAT 680) was estimated to be 9.7 meters long and weigh 2.3 tons. However, James Madsen says in his 1976 Aphrodite that the lengths of these dinosaurs ranged from 12 to 13 meters as a maximum, a conclusion he derived from studying the lengths of their bones. As is the case with all extinct creatures, it is difficult to estimate the weight of this animal. Since 1980, estimates have ranged from 1,000 to 4,000 kilograms. As for the weight of an adult animal, it was estimated at 1010 kilograms (which is the most frequently used weight, not the maximum). On the other hand, specialists who worked in the Morrison Formation believe that 1,000 kilograms is a reasonable weight for a large adult Allosaurus, and this weight may be reduced to 700 kilograms if the estimate depends on the size of the thigh bones.

Many fossils of large carnivorous dinosaurs have been attributed to Allosaurus, but very few are from it. For example, Saurophaganax (MCT 1708) is a genus biologically related to Allosaurus and may have reached a length of 10.9 meters. maximus", although recent studies indicate that it is a genus in its own right. Another possible species of Allosaurus is a specimen attributed to the genus Epanetreas (CAT 5767), which may have reached a length of 12.1 meters. There is also the recent discovery of a fragmentary skull from the Peterson quarry in the Morrison Rocks in New Mexico, and this large reptile may have been another species of the genus Saurophagancus.




skull

The skull and teeth of Allosaurus were specialized for hunting large animals. Paleontologist Gregory Powell estimated the skull length of Allosaurus to be 84.5 centimeters, and the length of its owner to be 7.9 meters. It had five teeth in each coming to the sweet jaw (which are the bones that make up the tip of the snout), while it had between 14 and 17 teeth in its upper jaw (as the number of these teeth was not necessarily related to the size of the jaw bones), and it had such a number of teeth in Its lower jaw, with an average of sixteen teeth, and as we move towards the back side of the skull - in general - these teeth become shorter and thinner. All of Allosaurus's teeth have needle-like edges, and these teeth fell out easily and were replaced by others, which is why they have so many fossils.

The skull had a pair of horns above and in front of the eyes, and these two horns consisted of an extension of the lacrimal bone, and their shape and size differed to distinguish all Allosaurus from others of its kind, and there were two small grooves in its skull that connected the nasal bone to these two horns. These two horns were probably covered by a keratin sheath (protein fibres), and they may have had many functions, including protecting the eyes from the sun, displaying to attract females, and sparring with other Allosaurus during mating (although these horns were fragile).

Indentations appear in the lacrimal bone of Allosaurus, which may have carried glands such as the salt gland. In the jaw, maxillary sinuses were more developed than they were in the ancestors of Allosaurus (such as Ceratosaurus and Marshusaurus), and these bones may have had a function in the sense of smell, as it is likely that they were a place for Jacobson's organ. The roof of the cranial nerve of Allosaurus was thin, perhaps to cool the brain.


The skeleton

Allosaurus had nine vertebrae in its neck, fourteen in its back, and five in its sacrum to support the hip, and the number of vertebrae in the tail is unknown and varies according to the size of the animal. The cervical vertebrae and the front part of the back had hollows similar to those of birds (which is the group that survives today from theropods, that is, carnivorous dinosaurs), and scientists speculate that they contained air sacs for breathing. The thorax was wide and formed a barrel-like bowl, especially compared to less evolved carnivorous dinosaurs such as Ceratosaurus. Allosaurus had abdominal ribs, and its bone tissue may have been incompletely formed, and an excavation has revealed traces of a wound in these ribs inflicted on Allosaurus during its life. Scientists did not realize until 1996 that the Allosaurus had a sternum bone, as they had missed a ventral rib.

Allosaurus's arms were short compared to its legs (the length of the arms did not exceed 35% of the legs), and it had three fingers on each hand with a large, strong and curved claw at the end. Allosaurus' arms were strong, and the forearm (below the elbow) was shorter than the humerus (before the elbow) in a ratio of 1:1.2. The wrist of Allosaurus has a crescent-shaped wrist, which is similar to other carnivorous dinosaurs, including Maniraptora, and the thumb was the largest of the three fingers, and it differed in shape from the other fingers. Allosaurus' legs were not long or suitable for fast running (unlike tyrannosaurids), and the claws on its feet were less developed and more hoof-like compared to other theropods, and each foot had three toes supporting the body in addition to an internal grin, which some paleontologists believe may have helped Catching small prey.


Category

Allosaurus belongs to the Allosaurus family, a family of large theropods (carnivorous dinosaurs) that fall under a larger group called Carnosauria. The family Allosaurus was created by the paleontologist Othniel Charles Marsh in 1878 to define the genus Allosaurus, but the term did not come into common use until the 1970s when paleontologists used it to classify Megalosaurids, another family of large theropods that fell into disuse (as they are thrown into For this reason, some classifiers replace the word “Allosaurus” sometimes with Miagalosauria and Antrodemus, and among the most important academic authors who do this are: Gilmore (1920), Von Hoen (1926), Romer (1956 and 1966), Steele (1970) and Walker (1970). 1964).

After the publication of the famous Mardsen essay in 1976, most classifiers preferred the term Allosaurus when talking about this family, although the boundaries of this family were not precisely defined, and as for less specialized books, they use the term Allosaurus to describe many large carnivorous dinosaurs. Among the theropods that were previously believed to be relatives of Allosaurus were: Endosaurus, Pyatintzosaurus, Paifetosaurus, Yangquanosaurus, Acrocanthosaurus, Chilantaosaurus, Composaurus, Stochiosaurus, and Sichuanosaurus. Scientists' knowledge of the types of theropods, their groups, and their evolutionary relationships has now improved. In light of this knowledge, all the previously mentioned dinosaurs are no longer classified in the Allosaurus family, although many of them (such as Acrocanthosaurus and Yangcanosaurus) are classified within families closely related to Allosaurus.

Allosaurus is one of four families in the Carnosauria, the other three being the Neovenatorids, the Karkaodontosaurs, and the Synraptoridae. Some have suggested - previously - that Allosaurus are the ancestors of Tyrannosaurids (which makes them semi-race), and a recent example of this suggestion is the book "Predatory Dinosaurs of the World" by the well-known researcher Gregory Powell, but this idea is now rejected based on the fact that Tyrannosaurids It belongs to a different branch of theropods called the coelurosaurs. Allosaurus is the smallest known family of Carnosauria, as it includes only three genera that are currently agreed upon: Allosaurus (to which the family name is attributed), Saurophaganax, and a type of relative of Allosaurus discovered in France that has not yet received a name. Recent reviews agree to leave the genus Saurophaganax within the family Allosaurus, and Epanetreas as a lineage of Allosaurus itself.


species

The diversity of Allosaurus is still a matter of debate among scientists, as studies have revealed seven possible species since 1988 (A. amplexus, A. Atrox, A. European, and the main type A. Fragilis, in addition to three other species that have no official description: A. Jemadseni, A. Maximus, and A. Tendagiorini), although academics change their opinion on it from time to time. At least 10 other species have been attributed to Allosaurus, some of which were classified in their own genus, but later it turned out to be a class of Allosaurus as well (such as Allapantrias and others). In most recent revisions of the classification of the ancestors of Allosaurus (in the titanourian branch of theropods), only a few species are accepted, namely A. fragilis (with A. amplexus and A. atrox as synonyms) and A. Gemadcenae (as an unnamed species) and A. Tandagyurini, and A. European it has not yet been reviewed and wa. Maximus merged with the saurophaganx.

The types of A. amplicus and a. atrox and a. Fragilis and A. Gimadsini are all known from bones discovered in the layers of the late Jurassic period between the Cammardian and Tetonian periods within the Morrison Formation in the United States of America, and they extend across the states: Colorado, Montana, New Mexico, Oklahoma, South Dakota, Utah and Wyoming. A. is considered Fragilis is the most common type of Allosaurus and the closest one to study, thanks to the large number of fossils that have been discovered. At least 60 individuals have been found. There is debate about the possibility of another common species in Morris, A. Atrox since the eighties of the twentieth century, but recent studies tend to the existence of only one species and not two, as the apparent differences in Morrison's formation were considered normal differences between each dinosaur and another of the same type. Type A fossils have also been discovered. European in the Lorraine Formation strata of the late Jurassic Camerodian period, but it could be the same species as A. Fragiles. As for a. Tendagyurini was found in the 'Tendaguru Fossil Area' in Mtwara, Tanzania. Although the most recent revisions initially approved it as an actual species - correctly classified - among the Allosaurus, it tends to be a titanuric ancestor of it or a purely predatory dinosaur similar to it. Although the matter is still vague, dinosaurs of this type were large, as they may have reached a length of about 10 meters and a weight of 2.5 tons.

Four genera, Antrodemus, Creosaurus, Labrusaurus, and Labrusaurus, have been classified as possible synonyms for Allosaurus. Most of them were considered synonyms of Allosaurus. fragilis, or was mistakenly added to the genus Allosaurus without being closely studied, and even its classification is based on dubious fossils. One of the exceptions to this trait is the Labrosaurus type. Ferox, and his name was given to him by the researcher Marsh in 1884 based on the fossil of a fragment of a strangely formed lower jaw, as it had a clear gap in the row of teeth at the edge of the jaw, in addition to that the back of the jaw was very wide and sunken to the bottom. However, subsequent research confirmed that the bone was in fact deformed, and it appears that the animal it belonged to was injured, and the back of the jaw had an unusual shape as a result of what scientists had mistakenly attached to the bones when collecting its fragments. It is now agreed that this fossil actually belongs to the species A. Fragiles.


Discovery and history

Initial discoveries and research

The discovery and early studies of Allosaurus were complicated by the many names with which it and other dinosaurs were described during the Bone Wars of the late 19th century. The first fossil of this organism in history was described in 1869, and it is a bone obtained by the scientist Ferdinand Vandevere Hayden from simple residents who found it in a valley called Middle Park near the village of Granby (Colorado), and it most likely originally came from the rocks of the Morrison Formation, and the people of The village when they found it "fossil horse hooves." Hayden sent this bone to Joseph Leidy, who conjectured that it was a fragment of a tail vertebra of some kind of creature, and initially attributed it to the European dinosaur genus Poyclopleuron and named the species Poyclopleuron. Valens »(Poicilopleuron valens), but later changed his mind and decided that the species to which greatness belongs deserves a separate genus, and he called it «Antrodemus», a genus that was classified within the Allosaurus family.

As for the discovery of Allosaurus itself, it is based on a sample whose serial number is “MBT 1930”, which is a bunch of shattered fragments of three vertebrae, a rib, a tooth, a toe bone and a right humerus bone (the latter was the most useful in subsequent studies and research). Othniel released Charles Marsh in 1877 called the name Allosaurus. Fragilis" on the dinosaur from which these bones came. The name Allosaurus comes from the Greek word "alos" (αλλος), which means "strange" and "tyre" (σαυρος), which means "lizard" or "lizard". others known at the time. As for the name of the species “Fragilis”, it comes from the Latin word “Fragilis”, which means “brittle”, and this is because its vertebrae have many cavities that make them appear fragile. These bones were discovered in the Morrison Formation located north of Canon City in the US state of Colorado. During the subsequent period, Marsh and his rival Edward Drinker Cope (who is his great rival in the discovery of dinosaurs) created many other genera based on similar shallow evidence, and other scientists have included these genera in the Allosaurus family. These include the Creosaurus and Labrusaurus of Marsh, and the Epanetrias of Cope.

Focused on making new discoveries to win competition, Marsh and Cope didn't care much about their own past discoveries (or in most cases those of their subordinates). In Wyoming, meanwhile, M. B. Fletch (having resumed work in Colorado) on an almost complete Allosaurus skeleton and many partial skeletons, as found by H. F. Hubble (one of Cope's students) discovered a dinosaur fossil in the Como Bluff area in Wyoming in 1879 and sent it to his boss Cobb, and this never cared for her, and the box in which the fossil was kept was not opened until 1903 (after Cope's death) and then it turned out to be one of the most complete theropod skeletons Discovered at that time, it was presented to the public in 1908 (today it is classified as MAT 5753). This skeleton (pictured) is in the famous pose of an Allosaurus leaning on the devoured skeleton of an Apatosaurus, drawn by Charles R. Knight has a painting of it (shown below the photo). This fossil is considered very important because it is the first carnivorous dinosaur skeleton that was erected in front of the public in a free position, and despite that, it has never received a scientific or academic description.

The multiple names of Allosaurus fossils led to great difficulties in studying and researching it, especially with the shallow description provided by Marsh and Cope about the fossils they discovered. Since their time, some scientists (such as Samuel Wendell Weston) have said that they invent many new names without the need for them. For example, Wellstone indicated in 1901 that Marsh did not find a clear difference between Allosaurus and Creosaurus, and the scientist gave Charles. And the. Gilmore in 1920 made a huge and influential effort to resolve the great overlap and confusion in this classification, and he concluded from his research that the tail vertebrae that Joseph Leidy attributed to “Antrodemus” were not actually different from the vertebrae of Allosaurus, so they must belong to the same dinosaur, and in this case preference is given to the name Antrodemus because it is the first, and then Antrodemus became the accepted name for this species for more than 50 years, except that James Madison changed this reality by publishing a search for fossils that he discovered in Cleveland-Lloyd and in which he stated that the name Allosaurus has priority, because the discovery of «Antrodimus» was based on features There are few, if any, anatomies and shallow information (for example, no one knows exactly where the only known Antrodemus bone was discovered). The name Antrodemus has remained common among academics to differentiate between the skull found by Gilmour and the one discovered by Madsen.


Cleveland Discoveries - Leold

Paleontologists have been unstructured excavating the Cleveland-Leyold dinosaur quarry in Emery County, Utah since 1927. William J. Stokes demonstrated the scientific importance of the site in 1945, but the massive excavations did not begin there until 1960, and it was initiated by a great collaboration of more than 40 researchers, and they found thousands of bones and fossils between 1960 and 1965. The importance of this quarry was great due to the abundance of Allosaurus fossils in it, and because these fossils are well preserved, and because there is little agreement among scholars on how to preserve them in this place. Most of the bones discovered at this site belong to the subspecies called Allosaurus. Fragilis (it is estimated that the fossils discovered at the site came from at least 46 Allosaurus, and the total number of dinosaurs preserved in the quarry is no less than 73) along with disjointed and overlapping fossils of other types of dinosaurs. Scientists wrote about a dozen research papers on the history of the excavations at the site, and these papers suggested many and contradictory explanations for how it was formed, including what suggested that the creatures preserved in it sank in a swamp, or that they were stuck in a silt pond, or that they fell dead due to drought and drought, or She fell into a deep well. Regardless of what really happened, thanks to the huge number of well-preserved fossils, Allosaurus has been revealed to researchers, making it one of the most famous carnivorous dinosaurs known. The remains and structures discovered in this quarry are suitable for almost all ages and sizes, as they range in length from less than a meter to 12 meters. It is useful in studying these bones that they are separated from each other because they are usually found fused together.


Modern Business: The Eighties - Today

The period following the publication of Madsen's monograph was marked by a major renaissance in studies dealing with topics related to the prehistoric life of Allosaurus (both subjects of fossil biology and fossil ecology). These studies covered many topics, such as skeletal change, growth, skull structure, hunting methods, the brain, the possibility of life as herds, and parental care of offspring. Re-analysis of ancient materials (especially of large Allosaurus specimens), new discoveries in Portugal, and the many highly complete specimens that have been found have also improved scientists' knowledge of these dinosaurs. The Polish paleontologist Gerard Gerlinski also discovered footprints believed to belong to Allosaurus in Bautov (Poland) during the early 2000s.


big al

Discovered in 1991, the skeleton of an Allosaurus called "Big L" (serial number MR 693), which is 95% complete and clear, is about 8 meters long. This specimen was discovered in an excavation near the city of Shell, Wyoming, in collaboration between the Rocky Museum and the University of Wyoming Geological Museum team. The discovery was led by a Swiss team headed by researcher Kirby Saber, the same team that later discovered the second structure (“Big Al Two”), which is the best of the allosaurus structures. Known preserved to this day.

The structure of "Big Al" is of particular scientific importance for the integrity and completeness of its preservation (which is what gave it its name), but it was - in fact - smaller than the average size of an Allosaurus. Fragiles. Beg-l was close to puberty at the time of his death, as it is estimated that he was only 87% developing. Breithaupt was the first to describe the structure of Beg-l in 1996, and 19 of his bones were fractured or showing signs of infection at the time, which may have been the cause of his death. "Big Al". Scientists noticed signs of disease in five ribs, five vertebrae, and four foot bones, in addition to many other bones that show osteoarthritis, and among other health problems that “Big Al” faced during his life was an injury to his right foot, and this injury may have affected his movement and walking, and it may have injured His left foot is also due to his having to walk with a lame gait.


historical environment

Allosaurus was the most common carnivorous dinosaur (that is, theropods) in a giant area of ​​fossil rocks of the American West called the Morrison Formation, as the bones of this dinosaur made up between 70 to 75% of all the bones of the theropods discovered there, and thus it was sitting at the top of the food pyramid in his environment. Geological studies indicate that the rocks preserved in the Morrison Formation originated in an environment with a semi-arid and humid climate punctuated by dry seasons and floodplains. Many plants flourished in this environment, including coniferous forests, riverside ferns, and sparse savanna plains.

The Morrison Formation was a rich hunting ground for fossils. As it discovered types of plants, including green algae, mushrooms, mosses, horsetails, ferns, and many species of conifers. As for the fossil animals that were discovered, they include bivalves, snails, rays-finned, frogs, salamanders, turtles, beak-headed animals, and lizards, in addition to terrestrial and marine crocodilians, many types of pterosaurs, dinosaurs, and ancient mammals (such as canapids). Among the carnivorous dinosaurs that were found in Morrison: Ornitholists, Torphosaurus, and Ceratosaurus, and the herbivorous sauropods Brachiosaurus and Amphisilias, in addition to ornithischians: including Camptosaurus and Dryosaurus, and Allosaurus bones are often discovered in the same location as Stegosaurus, Apatosaurus, Camarasaurus, and Diplodocus. Allosaurus was also discovered in rock formations in Portugal dating back to the late Jurassic period, and it is believed that it was close ecologically to the Morrison Formation as it harbored more marine creatures.

Allosaurus lived with other large predators, including Ceratosaurus and Torphosaurus, in both the United States and Portugal. It seems that these three dinosaurs differed in their lifestyle, based on what scientists have concluded from studying their anatomy and fossil sites. Perhaps the Trophosaurus and the Ceratosaurus preferred to live around the waterways, as their bodies were short and agile, which gave them an advantage in forests and bushes, while the Allosaurus was huge and its legs were longer and its movement was faster, but it was less able to camouflage itself, and it seems that it preferred to inhabit the dry floodplains. Ceratosaurus (about which we know more than we do about Torphosaurus) was markedly different from Allosaurus in its anatomy, having a longer, thinner skull with large, broad teeth in its jaws. Perhaps other predators attacked Allosaurus itself from time to time, as evidenced by the foot of Allosaurus bearing the marks of the teeth of another carnivorous dinosaur, and perhaps it was a ceratosaurus or a torphosaurus.


Biological properties

lifestyle

Allosaurus fossils are available in abundance from all stages of life, which allows studying the life period of these animals and how they developed. Scientists have found the remains of these dinosaurs from the beginning of their lives (when they are embryos in an egg). In Colorado, crumbs of eggs believed to belong to Allosaurus were discovered. Based on the analysis of the tissues of the bones of the limbs of these dinosaurs, the maximum age was estimated to range from 22 to 28 years, and this is close to the ages of other large carnivores of its time such as Tyrannosaurus. From the same analyzes, it appears that its growth is complete at the age of 15, and its growth rate is estimated at one hundred and fifty kilograms per year.

Researchers have discovered at least one bone marrow tissue from Allosaurus (which is also found in other dinosaurs including Tyrannosaurus and Tyrannosaurus), and it came from a forelimb bone from the Cleveland-Leyold quarry. This bone tissue is not formed in our time except in female birds laying eggs, as it helps in enveloping the egg with a layer of calcium, and the presence of this tissue in the female Allosaurus proves that she was an adult and of reproductive age, and it is mentioned that some studies have questioned this result. And by comparing the growth indicators, it was shown that the age of this female at her death did not exceed 10 years, and this indicates that the Allosaurus was sexually mature long before its completion.

Another discovery of a juvenile Allosaurus with hind legs that were about to grow to their maximum length shows that the hind legs are longer in juvenile Allosaurus, and the lower parts of the leg (i.e. the forelegs and feet) were relatively longer than the thigh. These differences indicate that the younger Allosaurus was faster at running and had different hunting strategies than the adult, as it may have chased small prey at this age, then when it reached puberty it changed its method and began to ambush large animals. Other changes associated with growth are that the femur of these dinosaurs thickens and widens with age, which similarly alters the ligaments of the muscles, making the muscles shorter and leg growth slowing: these changes mean that the juvenile Allosaurus walked mostly straight, unlike the adult. On the contrary, it appears that the skull bone was growing in parallel with the rest of the body, so that its size remained constant compared to the size of the body.


food

All paleontologists agree that Allosaurus was a predatory animal that preyed on large dinosaurs. It is most likely that the sauropods (herbivorous dinosaurs with long necks) were the most important prey of Allosaurus, and he may have hunted them alive or extracted their bodies from other animals and devoured them after their death (by gavage). A peduncle next to the bones of sauropods. Scientists have discovered amazing evidence of the battles between Allosaurus and Stegosaurus (another type of herbivorous dinosaur with a spiky tail), including the vertebrae of the tail of Allosaurus with a partially healed wound in which a fork from the tail of Stegosaurus was inserted, in addition to a neck plate of Stegosaurus with a curved wound shaped very close to a tooth segment. Allosaurus. But George Powell noted in 1988 that the capabilities of Allosaurus did not allow him to hunt full-grown sauropods unless he hunted in a group, as his skull was not very large and his teeth were relatively small, and his weight was significantly less than that of adult sauropods. Thus, it is likely that Allosaurus hunted juvenile herbivorous dinosaurs rather than large adults. Research conducted in the 1990s and 2000s found other solutions to this dilemma. Some scientists compared Allosaurus with contemporary predators (such as saber-toothed mammals), and found many common features between these two species, such as contraction of the jaw muscles and hypertrophy. Neck muscles and their ability to spread their jaws wide to widen their bite. Some scientists believe that the Allosaurus may have resorted to a method of attack commensurate with these adaptations in the neck and jaws:

Another study reached similar conclusions by analyzing the elements ending in the Allosaurus skull. According to their biomechanical analyzes, the skull was very strong, but its bite force was less than expected, as the Allosaurus was able (by relying on its jaw muscles) to bite with a force ranging from 805 to 2,148 Newtons. This is less than the strength of modern alligator bites (13,000), lions (4,167) and tigers (2,268), but despite this, the Allosaurus skull can withstand a vertical pressure of 55,500 Newtons on the jaw bones. Some authors believed that these dinosaurs used their heads like axes to hit their prey, as they attacked the victim with their mouths open and cut and ripped the flesh with their teeth without hurting the bones (unlike Tyrannosaurus, which is believed to have been able to shatter the bones of its opponents). The authors also believe that the structure of Allosaurus' skull allowed it to attack its prey in a different way: Its skull was so light that it could attack smaller and more agile ornithopods, but the skull was also strong enough to withstand powerful attacks against large prey such as stegosaurids and sauropods. But the interpretations of these writers contradicted other research, including what was not found between modern animals for this alleged “axe attack”, and considered that it was more likely that the skull with an open structure was strong and could bear the pressure that falls on it while resisting the prey. However, the researchers note, there is no analogue in the contemporary animal kingdom to Allosaurus, as no modern animal has a row of teeth prepared for such an attack and no joints in the skull designed to protect the palate and reduce pressure on it. She suggested another way of hunting that Allosaurus (and other carnivorous dinosaurs) might have followed, and she says that Allosaurus might have been able to bite sauropods and extract meat from their bodies without killing them, which means that he was getting enough food without the need to waste his effort in killing prey before it begins to devour it. It is also possible that this strategy made it possible to return to prey and feed on it later. Another belief indicates that ornithopods were the most common prey of dinosaurs, and that Allosaurus may have hunted in a manner similar to that of modern cats (eg, tigers and lions), by clinging to the prey with its arms and legs and biting the throat until it smashed its windpipe and suffocated it. This is consistent with other evidence that Allosaurus' four limbs were strong and could subdue their prey.

Other aspects of the Allosaurus' feeding methods include its eyes, arms, and legs. As the shape of the skull of this dinosaur limits it to binocular vision of twenty degrees (that is, its eyes share only twenty degrees of their field of vision), which is slightly less than the binocular vision of modern crocodiles. As is the case with crocodilians, this vision may have been sufficient to estimate the distance separating it from the prey and the appropriate time for the attack. And the wide field of view of Allosaurus indicates that it was a hunter that relied on ambushes and surprise attacks, as well as crocodiles. The arms (compared to those of other carnivorous dinosaurs) were designed to prevent the prey from moving and clinging to it closely at the same time, and the joints of the claws indicate that it was easily inserted into the flesh of the prey like a hook. Finally, the maximum speed of Allosaurus is estimated at 30 to 50 kilometers per hour.


social behavior

In the 1970s, there was a general perception that had circulated for a long time (especially in the general and non-specialist literature) that Allosaurus was a carnivorous animal that hunted in groups chasing sauropods and other large dinosaurs. Some scientists assume that the parents of Allosaurus were involved in caring for their children, and some scientists also interpret the fallen teeth of Allosaurus and the chewed bones of their large prey as evidence that the adult ones were taking food to their dens in order to feed their young until they grow, and for this reason the adult dinosaur protected its prey from its prey. Garbage animals (carnivores usually eat their fill, then return to their den, and the scavengers flock to eat what is left).

It is possible that Allosaurus hunted in groups, but there is a recent opinion that Allosaurus and other carnivores were acting aggressively with their kind rather than cooperating with them to hunt. Studies conducted to answer this question have found that group hunting for large prey is generally rare among vertebrates, as modern brachiopods (such as lizards, crocodiles, and birds, which are relatives of dinosaurs) hunt very rarely in this way. Instead, they lead a solitary life, and are more likely to kill or repel any intruders of their own kind into their territory, and will do the same with smaller animals that try to eat their prey before they finish their food. According to this interpretation, the accumulation of many allosaurus fossils at the same site (in the Cleveland-Leold Quarry) is not evidence of collective hunting, but rather because allosaurs used to gather in the same place to feed on a weak or dead dinosaur of their kind, and they were dying in the process. Perhaps this explains the presence of a high percentage of young and semi-adult Allosaurus in those sites, as this same phenomenon occurs between crocodiles and Komodo dragons. This interpretation could also apply to the dens, which he thought were evidence of parents feeding the young. I also discovered evidence that Allosaurus was devouring its own kind, which the researchers concluded from teeth found in the fossils of the ribs of other Allosaurus animals and from bite marks on the bones of Allosaurus. This interpretation could also apply to the dens, which he thought were evidence of parents feeding the young. I also discovered evidence that Allosaurus was devouring its own kind, which the researchers concluded from teeth found in the fossils of the ribs of other Allosaurus animals and from bite marks on the bones of Allosaurus. This interpretation could also apply to the dens, which he thought were evidence of parents feeding the young. I also discovered evidence that Allosaurus was devouring its own kind, which the researchers concluded from teeth found in the fossils of the ribs of other Allosaurus animals and from bite marks on the bones of Allosaurus.


The brain and the senses

Computerized X-ray imaging of Allosaurus fossils showed that its brain was more similar to that of crocodiles than other living archosaurs (such as birds). The structure of its vestibular apparatus indicates that the skull of Allosaurus was approximately similar in height to the back, and it is also likely that the composition of its middle ear was similar to that of the middle ear of crocodiles. Thus, Allosaurus may have been able to hear low sound frequencies, but it may have been difficult for it to hear very faint sounds. The olfactory bulb of this dinosaur was large and seemed to have been well prepared for capturing odors, although the area allocated for capturing odors was relatively small.

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