Two new colonies of a rare tadpole shrimp which date back over 200 million years have been discovered in Dumfriesshire, Scotland. Scientists now think it’s possible that other colonies are going undetected in the UK because of the creature’s strange lifestyle.
Triops cancriformis, or tadpole shrimp, is an endangered species that may be the oldest living animal species on earth. Fossils from the Triassic period, a time when many of the first dinosaurs evolved, has shown that this species has survived virtually unchanged when compared to their modern day descendents.
They have adapted to living in temporary water pools and so don’t survive for very long. When there is no rainfall these ponds usually dry up and the adult tadpole shrimps die. Their eggs however remain in a state of suspended animation, sometimes for many years, until the environment is suitable to allow them to hatch.
Knowledge of this unique lifestyle helped Glasgow University masters student Elaine Benzies discover the two new colonies at Caerlaverock on the Solway Coast. Having taken mud samples from pools around Caerlaverock, Miss Benzies dried and then re-wetted them in small aquaria. She was absolutely amazed to find a fairly large Triops swimming in one of the tanks within a couple of weeks.
Miss Benzies said, “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 including the cook from the canteen gathering round and peering into the tank to look at this ancient survivor from the past.”
Triops was long thought to be confined in the UK to a single pond in the New Forest. In 2004 Dr Larry Griffin of the Wildfowl & Wetlands Trust (WWT) discovered it at another, seemingly isolated, pool hundreds of miles away at Caerlaverock, Dumfriesshire.
Dr Griffin explains: “At the time it seemed that the Caerlaverock colony was a vulnerable, historic outlier on the northern fringe of its past and present population. 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 the 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.”
WWT, Glasgow University and Scottish Natural Heritage (SNH) have come together in a joint project to find out whether the species is more widely distributed but is going unnoticed because of its mostly hidden lifestyle.
Now that we know how this curious creature survives, we have realised that there’s a good chance there are more populations out there.
Professor Colin Adams of Glasgow University said, “It’s encouraging to get such a positive early result from this exploratory project. We must now extend its scope to widen the area of search for this rare and charismatic freshwater animal.”
Dr Colin Bean of SNH said, “Discovering that the Caerlaverock National Nature Reserve is such a stronghold for Triops is thrilling. Clearly there is more work to do if we are to discover how widely it is distributed, but these new findings are a real boost for Scottish wildlife – especially in this, the International Year of Biodiversity”.
Anyone who wishes to see Triops up close can do so at WWT Caerlaverock near Dumfries, where eggs are hatched in an aquarium during most months of the year. See wwt.org.uk/caerlaverock for more details.