Two new species of dinosaur that may have once roamed what is now the Isle of Wight 125 million years ago have been discovered.
The two carnivorous reptiles are thought to have been nine metres long (29.5ft) – about the same length as a Stegosaurus – with skulls like crocodiles.
One has been described as a “hell heron”, with scientists describing its hunting style like a fearsome version of the modern day bird.
One expert hailed the discovery of the two specimens in quick succession as a “huge surprise”, but said palaeontologists had suspected for decades that the remains of such dinosaurs could be found on the island.
Over a number of years, scientists discovered the bones on Brighstone’s beach. Scientists now believe they belong to two new species spinosaurids, which are predatory theropod dinosaurs that are closely related to the giant Spinosaurus.
More than 50 bones have been found from rocks from the Wessex Formation. These rocks were formed more than 125 millions years ago in the Early Cretaceous period.
Dr Neil J Gostling of the University of Southampton who supervised the project, said: “This work has brought together universities, the Dinosaur Isle museum and the public to reveal these amazing dinosaurs and the incredibly diverse ecology of the south coast of England 125 million years ago.”
The only spinosaurid skeleton previously unearthed in the UK belonged to Baryonyx, which was initially discovered in 1983 in a quarry in Surrey.
The majority of other discoveries since then have focused on single bones and isolated teeth.
Analysis of the Isle of Wight bones carried out at the University of Southampton and published in Scientific Reports suggested they belonged to species of dinosaurs previously unknown to science.
Chris Barker, a PhD student at the University of Southampton and lead author of the study, said: “We found the skulls to differ not only from Baryonyx, but also one another, suggesting the UK housed a greater diversity of spinosaurids than previously thought.”
Co-author Darren Naish, an expert in British theropod dinosaurs, said the discovery of spinosaurid dinosaurs on the Isle of Wight was a long time coming.
“We’ve known for a couple of decades now that Baryonyx-like dinosaurs awaited discovered on the Isle of Wight, but finding the remains of two such animals in close succession was a huge surprise.”
The first specimen has been named Ceratosuchops inferodios, which translates as the “horned crocodile-faced hell heron”.
With a series of low horns and bumps ornamenting the brow region, the name also refers to the predator’s likely hunting style, which would be similar to that of a heron.
Herons are well-known for their ability to capture aquatic prey at the edges of waterways. However, they can also consume terrestrial prey.
The second was named Riparovenator milnerae, which translates as “Milner’s riverbank hunter”, in honour of esteemed British palaeontologist Angela Milner, who died recently.
Dr Milner had previously studied and named Baryonyx – a major palaeontological event whose discovery substantially improved our understanding of these distinctive predators.
The Early Cretaceous rocks of the Isle of Wight depict an environment of floodplains that was Mediterranean-like.
Although the climate was generally pleasant, there were occasional forest fires that destroyed the landscape. The remains of burned wood can still be seen on the cliffs today.
A large river and other bodies water attract dinosaurs, and the habitat houses various fish, sharks, and crocodiles. This habitat will have provided spinosaurids plenty of hunting opportunities.
The new fossils will be on display at the Dinosaur Isle Museum in Sandown, Isle of Wight.