Discovered the oldest 'monstrosity'

A 155 million-year-old fossil in Utah reveals a bipedal carnivore that once inhabited western North America.

The new species, Allosaurus jmadmadseni , was identified as the genus Allosaurus (the monstrosity dragon) and is the oldest known member of the large two-legged carnivorous dinosaur. They have been roaming the Earth since 157-15 152 million years ago, according to a paper published in the scientific journal PeerJ on January 24.

Image reconstructing dinosaurs Allosaurus jimmadseni.(Graphic: Andrey Atuchin).

The fossil analysis showed that the adult Allosaurus jmadmadseni is about 8 - 9 m long and weighs 1.8 tons. It has a narrow skull, small horns located above the eyes, and a crest that runs from the horn to the nose. Each animal's limb consists of three sharp claws.

"Previously, paleontologists believed that there was only one abnormality in North America, the Allosaurus fragilis. However, new research shows that Allosaurus jimmadseni was on Earth earlier than his relative. it's at least 5 million years, " said Mark Loewen, lead author of the study. "A. jimmadseni's skull is significantly lighter than A. fragilis, which explains the different hunting behavior between the two species."

A group of A. jimmadseni collaborated on hunting another larger dinosaur.(Graphic: Todd Marshall).

According to the research team, A. jimmadseni lives and hunts in groups. They once thrived in flooded plains, today the area of ​​Colorado, Utah and Wyoming in western North America during the late Jurassic period.

"The new findings once again show the importance of paleontological research in Western lands. The discovery of A. jimmadseni will provide important information about prehistoric Jurassic life in the Jurassic. North America, " noted co-author of the study Brent Breithaupt.

• Discovered new carnivorous dinosaurs
• Animals repel carnivorous dinosaurs by only flicking their tails
• 'Biggest predator' rewrites dinosaur history