Description: This isopod has an elongate, slim, oval body with obvious segments aside from the posterior of the animal where the segments are fused. Here the pleon and telson fuse to form the pleotelson which is slightly keeled towards the back and has a fine rounded tip in the centre. Males grow 5-15 mm long while females reach 6-10 mm. It is usually a uniform green or brown in colour but can sometimes have white markings. Females may be darker in colour. The have two long antennae and small eyes.

Habitat: Favours brackish water or habitats. Found intertidally among algae in sheltered estuaries or on green algae in sheltered brackish pools on the upper shore.

Distribution: Recorded all around Britain and Ireland.

Similar Species: Could be confused with other Idotea species. Usually, careful inspection of the shape of the pleotelson helps distinguish between species.

Key Identification Features:

• Elongate and slim oval body.
• Pleotelson has fine rounded tip in centre.
• Usually uniform brown or green in colour but may have white markings.

Distribution Map from NBN: Idotea chelipes at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Idotea chelipes at iNaturalist World Species Observations database.

GBIF data for Idotea chelipes

WoRMS: Idotea chelipes at World Register of Marine Species. Accepted name: Idotea chelipes (Pallas, 1766). AphiaID: 119042.

Classification: Biota; Animalia; Arthropoda; Crustacea; Multicrustacea; Malacostraca; Eumalacostraca; Peracarida; Isopoda; Valvifera; Idoteidae; Idotea