Allosaurus (Allosaurus): description, characteristics, photo

Allosaurus (lat. Allosaurus; Greek. αλλος “other” or “strange”, σαυρος “lizard”) a genus of predatory lizard dinosaurs of the theropod suborder. They lived in the Jurassic period (Kimmeridgian early Tithonian) about 155-145 million years ago.

Allosaurs 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. Allosaurus remains are known from North America, Southern Europe, and East Africa.

The first remains were studied and classified in 1877 by Othniel Charles Marsh.

Allosaurus was a large, bipedal carnivore with a large skull equipped with dozens of large, sharp teeth. Representatives of the type species A. fragilis (lat. A. fragilis) averaged 8.5 meters in length, 3.5 meters in height and weighed about a ton, although, based on larger fragmentary remains, it can be suggested that large individuals could reach up to 11 meters in length, about 4 meters in height and weight 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.

Selected types:

Allosaurus fragilis (fragilis fragile) type species, described by O. H. March in 1877. Late Jurassic (Kimmeridgian Early Tithonian) of western North America. Known from a huge number of specimens, including complete skeletons of various sizes, individuals of various ages from Colorado, Utah, Wyoming, New Mexico. Described mass graves in viscous asphalt or mud “traps for predators”, in Cleveland Loyd (40 individuals). Length up to 8.5-12.3 meters, weight from 1 to 2 tons, height 3.5 meters.

Allosaurus atrox (Creosaurus) smaller and with a lower skull, from Wyoming. The true status of Creosaurus is unknown, but among the allosaurs of the species Allosaurus fragilis, two groups of forms with preorbital horns of different configurations are observed. Perhaps this reflects gender differences.

Recently, on the basis of finds of almost complete skeletons in Utah and Wyoming, the species Allosaurus jimmadseni has been identified, the validity of which is not recognized by all authors.

Allosaurus europaeus from Late Kimmeridgian Early Tithonian of Portugal. Extremely similar to the type species, described from an incomplete skull in 2006.

Allosaurus maximus is a giant (weighing more than 2 tons, up to 11-12 meters long) allosaurus from the Kimmeridgian of Oklahoma and Colorado. True status unknown. Allosaurus maximus proper from Oklahoma is often separated into a separate genus Saurophaganax.

The same type is sometimes attributed to a giant allosaurus of Epantherias (Epanterias amplexus) from Colorado, which is usually considered a large type of typical species.

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

It was not a big deal for paleontologists to reconstruct the appearance of the Allosaurus, since over 60 of its skeletons of various sizes have already been found in America. 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 the initial period of life of these lizards was like.

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. At the same time, three fingers were turned forward, and one was turned back.

This structure of the fingers helped the Allosaurus to maintain a stable balance, standing on two legs, and also to easily overtake any prey. 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 brow 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 led a predatory lifestyle. Their prey were various herbivorous dinosaurs, which is confirmed by the found piece of the tail of the Apatosaurus, which preserved deep marks from the bite of the Allosaurus 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 of the Jurassic period. 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 ancient times there was a swamp in this place. By its negligence, a giant brachiosaurus wandered there 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”.

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