A new species of carnivorous dinosaur has been discovered following the analysis of some fossils preserved in the Natural History Museum of Utah. The skeleton remains were found during the early 1990s in northeastern Utah. According to researchers, it was a large carnivorous dinosaur that lived in a habitat made up of floodplains and intricate systems of waterways, lakes and mudflats in western North America between 157 and 152 million years ago (late Jurassic).

It was a species of allosaurus and was named Allosaurus jimmadseni by researchers (the second term refers to the paleontologist James H. Madsen Jr.). The species is described in a new study appeared on PeerJ. Among the unique features of this species the short and narrow skull with relatively small facial crests from the horns to the eyes.

The species resembled a much better known younger cousin, the Allosaurus fragilis, from which, however, it seems to differ in a smaller field of vision and a lighter and more contained skull.

The jimmadsenisi was between 8 and 9 meters long and weighed about 1.8 tons. It was wanted before the fragilis, at least 5 million years before, and was one of the most ravenous predators of its habitat with its long legs and arms equipped with three powerful sharp claws.

This is an important discovery because it shows that in North America there were not only one species of allosaurus but at least two, as Mark Loewen, professor of the Department of Geology and Geophysics of the University of Utah, who conducted the study, explains.