Because of its size, the new carnivore is thought to have eaten juvenile or small dinosaurs, which were common during the Late Cretaceous period when the animal lived.
The fossil was found in a region of Mongolia's Gobi desert known as the Nemegt Formation, an area where many dinosaur bones have been found before. 
It is thought the beast was a pterosaur, a group of giant flying reptiles that lived alongside the dinosaurs.
The animals were the first vertebrates known to evolve the power of flight, and are thought to have been the largest flying animals ever seen on Earth.
While the species unearthed in Mongolia has not yet been identified, researchers were struck by the sheer size of the backbone fragments found.
'I immediately recognised that it might be a pterosaur and was astonished at its gigantic size,' palaeontologist Dr Takanobu Tsuihiji from the University of Tokyo told National Geographic.

'Straight away, we went back to the site and discovered the rest of the specimen.'