An article published in the journal “PeerJ” reports the identification of a new species of carnivorous dinosaur that lived between 152 and 157 million years ago, in the Jurassic period. Daniel Chure and Mark Loewen named it Allosaurus jimmadseni after examining various fossils discovered in the 1990s in Utah and Wyoming to determine that it’s a new species of allosaurus, a few million years older than the first one discovered, Allosaurus fragilis. The differences between the two species suggest different eating habits.
Allosaurs were carnivorous dinosaurs that were top predators in their ecosystems. T. rex is more iconic than allosaurs but members of this group of theropod dinosaurs were fierce hunters. The members of the genus Allosaurus ended up giving the name to the entire family of allosaurids (Allosauridae), in which the taxonomy is still under discussion because over the years several species have been proposed but some have been subsequently recognized as synonyms of species already classified. This isn’t an uncommon case in the field of paleontology because scientists often have to study incomplete skeletons. Today communications allow a rapid spread of studies and new technologies help the classification of fossils so the situation is improving.
A fossil skeleton was discovered in 1990 in the Dinosaur National Monument on the Colorado-Utah border. It was headless but the skull was discovered in 1996 following a radioactive trace due to the surrounding rocks. Meanwhile, in 1991, another specimen was discovered in Wyoming and nicknamed “Big Al”. In subsequent years, other specimens were recognized as possible belonging to the same species in museum collections.
The two researchers determined that it’s a different species from Allosaurus fragilis due to some anatomical differences, particularly in the characteristics of the skull. Like its cousin, it was a large predator with a length of 8-9 meters and a weight close to 2,000 kilograms. It had relatively long legs and tail and three sharp claws on each arm. The large head had a mouth with 80 sharp teeth.
The discovery of a new allosaurid is important because it was an animal at the top of its food chain, so its presence had a significant influence on its ecosystem. According to Dr. Daniel Chure, it also shows that there’s still much more to learn about the world of dinosaurs.
