The fossils of a new species of meat-eating dinosaurs have been unveiled at the Natural Museum of Utah. The dinosaur, called Allosaurus jimmadseni, is believed to be the oldest species of Allosaurus to have existed in the Late Jurassic Period, some 157-152 million years ago.
The A jimmadseni was first discovered by Paleontologists in early 1990s in Dinosaur National Monument in northeastern Utah and it predates one of most familiar of its species, the Allosaurus fragilis. The name ‘jimmadseni’ was given to this species to honour the palaeontologist James H Madsen Jr, whereas the genus name Allosaurus means ‘different reptile’
Allosaurus is a carnivorous bipedal dinosaur and also one of the best-known theropod dinosaurs from the Jurassic and Cretaceous periods. Based upon a complete articulated skeleton and skull along with a second specimen with an articulated skull and associated skeleton, Paleontologists say that A jimmadseni was about 26 to 29 feet and weighed in at least 4000 pounds.
With its long arms, legs, and claws, the new-found allosaurus species is believed to have been the apex predator in its ecosystem when it existed in North America. A jimmadseni also had a short narrow skull that was relatively weaker with less of an overlapping vision compared to the A fragilis. This led the researchers to think that both species had different feeding behaviours.
Researchers say that the Morrison Formation of North America hosted only two species of Allosaurs– A fragilis and A jimmadseni, of which the former is believed to have evolved about 5 million years after the jimmadseni.
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“Recognizing a new species of dinosaur in rocks that have been intensely investigated for over 150 years is an outstanding experience of discovery. A jimmadseni is a great example of just how much more we have to learn about the world of dinosaurs,” Co-author of the study Daniel Chure said. “Many more exciting fossils await discovery in the Jurassic rocks of the American West.”