THEY have used the latest technology to unlock the secrets of the past.

Experts at Southampton University have shed new light on the swimming style of a prehistoric sea creature by creating a robot to mimic its movements.

Their discoveries have helped explain a long-standing riddle and could also lead to the development of quieter and more efficient submersibles.

The team studied the propulsion method of plesiosaurs – marine reptiles that lived at the same time as the dinosaurs and died out more than 65 million years ago.

Plesiosaurs had two almost identical pairs of flippers, making them unique among vertebrates.

Other sea creatures used their front flippers for thrust and their back ones for steering – and some species, such as turtles, still do.

The revolutionary system used by plesiosaurs has sparked speculation what type of swimming stroke they used.

In a paper published today, Luke Muscutt and his fellow Southampton researchers describe a series of experiments using 3D printed flippers attached to a robotic mechanism.

They studied plesiosaur fossils and X-rays of current creatures to determine the shape of the large, wing-like flippers.

The team discovered that swirling movements created in the water by the front flippers made the back ones more efficient, suggesting that plesiosaurs used all four to propel themselves through the water.

Luke said: “Fossils by themselves don’t tell us much about how plesiosaurs actually moved.

“Short of genetically engineering a plesiosaur, our best available option was to create a robot to show how it might have happened.

“Understanding how an animal might have moved gives us a better understanding of the animal as a whole, including how far it could travel and what it might have fallen prey to.

“Our observations of tandem flipper systems might eventually have a real-world application - for instance a propulsion system for undersea vehicles that could help make them more manoeuvrable, efficient and quieter.”

Luke worked in conjunction with Bristol University. Colin Palmer of Bristol University’s School of Earth Sciences, said: “Our results resolve a long-standing debate about the mechanics of plesiosaurs swimming and demonstrate the effectiveness of the tandem flipper arrangement.”