A rare shrimp that may be the most ancient animal species on earth is alive and well in Britain, scientists have discovered.

Two colonies of the tadpole shrimp, triops cancriformis, were found at Caerlaverock on the Solway Coast of Dumfriesshire in Britain, researchers from the University of Glasgow announced.

Experts think there could be more 'hidden' population of the crustacean - an endangered species - elsewhere, says a Telegraph report.

The tadpole shrimp may have the oldest pedigree of any living animal, scientists believe.

Fossil finds show that the shrimp has stayed virtually unchanged since the first days of the dinosaurs. And after 200 million years, the tadpole shrimp is still showing the extraordinary ability to survive.

The shrimps are adapted to living in temporary water pools and when the water dries up, the adults die but leave behind eggs that can remain dormant for years until wet conditions return.

Mud, thought to contain tadpole shrimp eggs, was sampled from pools around Caerlaverock, dried, re-wetted and placed in small aquaria. The scientists were startled to find a large shrimp swimming in one of the tanks within a couple of weeks.

Research student Elaine Benzies said: 'I did not expect it and was just going in to check on the heat and lights. It was great to see everyone in the lab, including the cook from the canteen, gathering round and peering into the tank to look at this ancient survivor.'

The tadpole shrimp was long thought to be confined to a single pond in the New Forest, Hampshire.

Then in 2004 Dr Larry Griffin of the Wildfowl and Wetlands Trust (WWT) found another colony in a pool at Caerlaverock.

Dr Griffin said: 'At that time it seemed that the Caerlaverock colony was a vulnerable, historic outlier on the northern fringe of its past and present population.'