A 180 million-year-old fossil has shed light on how some ancient crocodiles evolved into dolphin-like animals.
The specimen - featuring a large portion of backbone - represents a missing link in the family tree of crocodiles, and was one of the largest coastal predators of the Jurassic Period, researchers say.
The newly discovered species was nearly five metres long and had large, pointed teeth for grasping prey.
Some Jurassic-era crocodiles had bony armour on their backs and bellies, and limbs adapted for walking on land.
Another group had tail fins and flippers but did not have armour.
The new species was heavily armoured but also had a tail fin, suggesting it is a missing link between the two groups, researchers say.