Tadpole shrimp

Description

Triops cancriformis, or tadpole shrimp, is a species of tadpole shrimp found in Europe to the Middle East and India. Due to habitat destruction, many populations have recently been lost across its European range, so, the species is considered endangered in the United Kingdom and in several European countries.In captivity they commonly grow up to 6 centimetres (2.4 in); in the wild they can achieve sizes of 11 cm (4.3 in). In the UK, there are just two known populations: in a pool and adjacent area in the Caerlaverock Wetlands in Scotland, and a temporary pond in the New Forest. The species is legally protected under Schedule 5 of the Wildlife and Countryside Act 1981 (as amended). Fossils from the Upper Triassic (Norian) of Germany, around 237 million years old have been attributed to this species as the subspecies T. cancriformis minor, due to their great similarity to modern day members of the species. However, later research showed that their ontogenetic growth was quite different from the living species, and they were better considered a distinct species, "Notostraca" minor, with an uncertain position within Notostraca. Genetic evidence also indicates that T. cancriformis only diverged from other Triops species around 23.7–49.6 million years ago.