A fossilised tooth belonging to an ancient underwater predator has been recorded as the largest of its kind found in the UK, scientists have said.
A team of palaeontologists found the 5.5cm tooth belongs to a prehistoric relative of modern crocodiles known as Dakosaurus maximus.
It was dredged from the sea floor near Chesil Beach in Dorset. Researchers and curators from the University of Edinburgh and the Natural History Museum in London identified it after it was bought at an online auction by a fossil collector about a year ago.
The tooth, which has a broken tip, is now in the fossil collection of the Natural History Museum.
Dakosaurus maximus grew to around 4.5 metres in length and swam in the shallow seas that covered Europe 152 million years ago, according to t he team's research published in the scientific journal Historical Biology.
The shape of its skull and teeth suggest it ate similar prey to killer whales, using its broad, short jaws to swallow fish whole and to bite chunks from larger prey.
Dr Mark Young, from the university's School of Biological Sciences, said: "Given its size, Dakosaurus had very large teeth. However, it wasn't the top marine predator of its time, and would have swum alongside other larger marine reptiles, making the shallow seas of the Late Jurassic period exceptionally dangerous."