The colossal 180 million-year-old fossilized remains of an ichthyosaur have been found in the UK, in what researchers have described as one of the most significant discoveries in the region.

Discovered in a reservoir in the county of Rutland, in the English East Midlands, the specimen is the largest and most complete ichthyosaur fossil ever found in the UK, measuring nearly 33 feet in length.

It is also thought to be the first of its particular species — Temnodontosaurus trigonodon — to be found in Britain.

Marine reptiles that lived alongside the dinosaurs, ichthyosaurs resembled dolphins in body shape. They became extinct around 90 million years ago, after first appearing 250 million years ago.

The ichthyosaur was first uncovered in February last year in the Rutland Water Nature Reserve by Joe Davis, a conservation team leader from Leicestershire and Rutland Wildlife Trust, which operates the nature reserve in partnership with the owner Anglian Water.

“The size and the completeness together are what makes it truly exceptional,” Lomax told CNN, adding that previous finds of ichthyosaurs in the UK had been “nowhere near as complete and as large as this.”