A fortnight  later research student, Elaine Benzies noticed a tadpole shrimp swimming around in one of the aquariums.

"I hadn't expected to find it and was just going in to check on the heat and lights. It was great to see everyone in the lab gathering round and peering into the tank to look at this ancient survivor from the past," she said.

Until recently, researchers believed the shrimps lived only in a single pond in the New Forest in Hampshire. Six years ago, Larry Griffin, a scientist at the Wildfowl and Wetlands Trust, discovered what appeared to be an isolated colony of the creatures in a pool at Caerlaverock.

"At the time it seemed that the Caerlaverock colony was a vulnerable historic outlier," he said. "But now that we know how this curious creature survives, we have realised that there's a good chance there are more populations out there.

"Triops matures rapidly and produces hundreds of eggs in just a couple of weeks. The pond they live in may dry out, but eggs can survive in the mud for many years. Although in the UK they are all females, they have both male and female reproductive parts, so just one egg needs to survive to regenerate a whole population."