Prehistoric remains discovered more than a century ago have been identified as a new species of marine super-predator.
Researchers said the 165-million-year-old creature was distantly related to modern-day crocodiles.
Parts of its skeleton were found near Peterborough in the early 1900s and are held at Glasgow's Hunterian museum.
The species has been named as Tyrannoneustes lythrodectikos, meaning "blood-biting tyrant swimmer".
Scientists found that the partial skeleton - including a jawbone and teeth - belonged to a group of crocodiles that were similar to dolphins.
The animal's pointed, serrated teeth and large gaping jaw meant it would have been suited to feeding on large-bodied prey.
A team of experts led by the University of Edinburgh said it would help scientists better understand how marine reptiles were evolving about 165 million years ago.'Missing link'
The researchers believe the species represents a missing link between marine crocodiles that fed on small prey, and others that were similar to modern-day killer whales, which fed on larger prey.
Their findings have been published in the Journal of Systematic Palaeontology.
Dr Mark Young of the University of Edinburgh's School of GeoSciences, said: "It is satisfying to be able to classify a specimen that has been unexamined for more than 100 years, and doubly so to find that this discovery improves our understanding of the evolution of marine reptiles."
Dr Neil Clark, palaeontology curator at the Hunterian, said little research had been done on the specimen since it was first listed in 1919.
He added: "It is comforting to know that new species can still be found in museums as new research is carried out on old collections.
"It is not just the new species that are important, but an increase in our understanding of how life evolved and the variety of life forms that existed 163 million years ago in the warm Jurassic seas around what is now Britain."