Open the dinosaur, which became the nightmare of the Jurassic period

Long known that the authors of the franchises, “Jurassic Park” made a mistake, making the most fierce and dangerous predator Tyrannosaurus Rex, which actually lived on the Earth in the Cretaceous period.

But paleontologists known bloodthirsty monster that definitely would have passed the casting for this role and, unlike the t Rex, lived on our planet in the Jurassic period.

we are talking about the predator of the new species called Allosaurus jimmadseni, who lived in North America 157-152 million years ago.

the Length of its body was up to nine meters, and the height reached 1.8 tons.

According to paleontologists, A. jimmadseni is the youngest representative of allosaurus. These theropods like the tyrannosaurs were the most dangerous predators of its time and was located at the top of the food chain. By the way, there are external similarities, allosaurus walked on its powerful hind legs and had long tails, and their forelimbs were relatively short.

the fossil remains of A. jimmadseni were extracted from the Morrison formation in the Western part of the United States. In fact, since the end of XIX century in this place were found many skeletons of allosaurus, but paleontologists disagree on which types could be fossils.

In the new work, the researchers studied two nearly complete skeletons: one was discovered in 1990 and one year later. It turned out that the remains belong to allosaurus in two types – standard and the new A. fragilis and A. jimmadseni.

By the way, the name of a new kind perpetuates the memory of paleontologist James Madsen, Jr. (James Madsen Jr.), who found and studied tens of thousands of bones of allosaurus.

the study of the remains A. jimmadseni, initially identified as DINO 11541, was not easy. For separation of the solid fragment with fossils from the surrounding rocks had to use explosives and for the transportation of the resulting block weighs about 2700 pounds took a helicopter.

CEfive years scientists have spent on the preparation of bones for analysis.

in addition, the paleontologists could not find the skull DINO 11541. This discovery was made in 1996 by radiologists: they used the radiation detector to detect gamma rays emanating from the skull. (Over time, of radioactive elements can be leached from the surrounding sediment and get into fossils).

In the course of the work paleontologists have discovered a number of anatomical features that distinguish A. jimmadseni from other species, including A. fragilis, a close relative, which appeared five million years later.

In particular, the allosaurus had a short and narrow skull, as well as the specific pair of ridges running from the nose and above the eyes passed into the horns. The latter is an enlarged brow ridges, and served probably to protect the eyes from strong sunlight.

it is Also noted that compared to A. fragilis from its “big brother” was less a field of stereoscopic vision.

However, despite the relatively primitive traits, A. jimmadseni were the top predators of its time. They hunted large prey, for example, the stegosaurus, the Diplodocus and other plant-eating dinosaurs.

According to paleontologists, the theropod used for capture of prey, three sharp claws on his front paws. Also in the Arsenal A. jimmadseni was about 80 razor-sharp teeth.

“Everyone knows allosaurus or think you know. But now, nearly 150 years after the discovery of the first bones of allosaurus and the collection of dozens of skeletons, it was found that there is another kind. This suggests that we need to continue to look for fossils, consistently study the fossils that we have, and continue to reassess all of the evidence. There are still a lot of dinosaurs that we will open,” writes paleontologist Stephen Brusatte not taking part in the new work.

Note that initially A. fragilis was considered the only species of allosaurus, aboutItachi in North America. Now, however, paleontologists believe that there could be up to 12.

read More new species of allosaurus is described in an article published in the journal PeerJ.

by the Way, before “Conduct.Science” ( talked about the apex predators of the Triassic with grotesquely big heads and the largest carnivorous dinosaur in the world.