A previously unidentified fossilized bone has been used by researchers from Imperial College London to reveal the size of an ancient dinosaur and may have shed light on a 100-year-old mystery. Researcher Alessandro Chiarenza, whose analysis revealed that it was a femur bone originating from a dinosaur called the abelisaur, discovered the fossil of the ancient creature, which lived on the Earth 95 million years ago during the late Cretaceous period.

Abelisauridae was a group of predatory carnivores that possessed small forelimbs, tiny razor sharp teeth and possibly even fluffy feathers. After careful analysis of the bone, the team was able to gauge the size of the dinosaur back in its time - around 9 meters long. Furthermore, they also predicted that it weighed between one and two tons, which means it is likely one of the largest abelisaurs ever discovered.

"Smaller abelisaur fossils have been previously found by palaeontologists, but this find shows how truly huge these flesh eating predators had become," Alfio Chiarenza said in a press release. "Their appearance may have looked a bit odd as they were probably covered in feathers with tiny, useless forelimbs, but make no mistake they were fearsome killers in their time."

In addition to information regarding their size, the research reveals that the previous notion that these dinosaurs lived closely to other groupings of predatory dinosaurs is false. This notion stems from the harsh and changing geology of the region that mixed fossil fragments together, effectively destroying their chronological ordering and presenting the illusion that the predatory dinosaurs in the region lived side by side.

"This fossil find, along with the accumulated wealth of previous studies, is helping to solve the question of whether abelisaurs may have co-existed with a range of other predators in the same region," Chiarenza said. "Rather than sharing the same environment, which the jumbled up fossil records may be leading us to believe, we think these creatures probably lived far away from one another in different types of environments."

The next step for the team is to continue searching for more comprehensive abelisaur remains that can continue to add to what we know of their environment and evolutionary history.

The findings were published in the Feb. 29 issue of PeerJ.