British Cave shrimp
The British cave shrimp is a rare and ancient creature living in the South West’s watery underworld.
Latin name: Niphargus glenniei
Notable feature: No eyes, white, smaller than most other cave shrimps (3mm long)
Rarity in the UK: Rare / Common
Where in the UK: Devon and Cornwall
Dweller of the darkness
The British cave shrimp is a 3mm-long species of blind cave shrimp which is only found in Devon and Cornwall. Its main habitat is groundwater aquifers, so the species turns up in caves, mines, springs, wells and boreholes . The darkness of their habitat makes eyes useless, so the shrimps have lost them completely. Instead, they have extra-long legs and antennae to feel around and to detect food, consisting of mats of microorganisms growing on surfaces and organic matter washing in from above.
The naming of the shrimp
The shrimp gets its scientific name from Brigadier E.A. Glennie of the Cave Research Group, who observed them in 1948. Specimens were given to the Plymouth Marine laboratory, where they were named as a species four years later.
Despite their fairly recent discovery, British cave shrimps have an ancient lineage. DNA evidence shows Niphargus species arose about 88 million years ago, 23 million years before the dinosaurs went extinct! Groundwater crustaceans were also amongst the few invertebrates that weathered the ice age in the UK. Living underground kept them insulated from the frozen surface. The British cave shrimp and its close Irish relative N.irlandicus are currently believed to be the oldest animal species in the British Isles, present for at least 19.5million years.
However, N.glenniei is threatened in modern times by pollution of groundwater with sewage and fertiliser run-off. The impacts on the shrimps are not fully understood, since their secluded habitat makes them difficult to study. The British cave shrimp is listed under section 41 of the Natural Environment and Rural Communities Act 2006, so local authorities have a duty to conserve them.
Did you know?
Aquatic animals which live underground are called Stygobites. There is a special recording scheme for stygobitic crustaceans , the Hypogean Crustacea Recording Schemeencouraging the public to submit records of these little-known species.