Paleontologists at the University of Southampton spent months studying four bones that were found last year in the village of Shanklin, on the Isle of Wight, off the south coast of England.

They finally determined that the bones were from the neck, back and tail of a new dinosaur ‘previously unknown to science,’ according to a release from the university.

The dinosaur would have measured about 4 meters (about 13 feet) long, and is a type of theropod dinosaur — a group of carnivores that typically walked on two legs instead of four, which includes the Tyrannosaurus rex. It lived in the Cretaceous period, about 115 million years ago, according to the release.

Scientists named the dinosaur Vectaerovenator inopinatus — a name that refers to large air sacs in some of the bones, which are commonly seen in theropods, and which helped the researchers identify the species. The sacs are also seen in modern birds; they likely helped create an efficient breathing system in these dinosaurs, while also making the skeleton lighter.

‘We were struck by just how hollow this animal was — it’s riddled with air spaces. Parts of its skeleton must have been rather delicate,’ said Chris Barker, a PhD student at the university who led the study. ‘The record of theropod dinosaurs from the mid Cretaceous period in Europe isn’t that great, so it’s been really exciting to be able to increase our understanding of the diversity of dinosaur species from this time.'”