152-million-year-old fearsome marine creature ate like modern-day killer whales

A fossilised tooth belonging to a fearsome marine predator has been recorded as the largest of its kind found in the UK, following its recent discovery.

A team of palaeontologists have verified the 5.5 cm long tooth, which was found near Chesil Beach in Dorset, as belonging to a prehistoric relative of modern crocodiles known as Dakosaurus maximus.

The unusual shape of the animal's skull and teeth suggests it ate similar prey to modern-day killer whales. It would have used its broad, short jaws to swallow large fish whole and to bite chunks from larger prey.

Dakosaurus maximus, which grew up to about 4.5 metres long, swam in the shallow seas that covered Europe some 152 million years ago. It belonged to a family of marine animals known as thalattosuchians, relatives of today's crocodiles.

Dr Mark Young, of the University of Edinburgh's School of Biological Sciences, said that given its size, Dakosaurus had very large teeth but wasn't a 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.

The research has been published in the scientific journal Historical Biology.