Description: A small crab (< 1 cm) with a rounded carapace and long conspicuous antennae. Colouration varies from red-orange to red-brown and there is occasionally a large white patch on the carapace. Clean appearance, not hairy. First pair of legs are long pincers, three pairs of walking legs with the fifth pair of legs small in size and often not visible. Not a ‘true’ crab, but more closely related to hermit crabs and squat lobsters.

Habitat: Under boulders on the lower shore and shallow sublittoral; also found in kelp holdfasts.

Distribution: Common on all coasts of Britain and Ireland.

Similar Species: Unlikely to be confused with any other species. Closest in resemblance is the broad-clawed porcelain crab (Porcellana platycheles) but this species is covered in small hairs and greyish-brown in colour.

Key Identification Features:

• Small crab (< 1 cm)
• Large conspicuous antennae
• Round red-brown/red-orange carapace
• Clean appearance

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

iNaturalist: Pisidia longicornis at iNaturalist World Species Observations database.

GBIF data for Pisidia longicornis

WoRMS: Pisidia longicornis at World Register of Marine Species. Accepted name: Pisidia longicornis (Linnaeus, 1767). AphiaID: 107188.

Classification: Biota; Animalia; Arthropoda; Crustacea; Multicrustacea; Malacostraca; Eumalacostraca; Eucarida; Decapoda; Pleocyemata; Anomura; Galatheoidea; Porcellanidae; Pisidia