Description: This caprellid is up to 25 mm long, with a smooth body and rounded head. The most important features in this species are the pereopods. Pereopod 3 and 4 (located around the centre of the animal, on the thorax or pereon) are fully developed and have 6 articles or segments. In other species these are less well developed or absent completely. The first set of antennae are at least half the length of the entire body but can be longer and can be equal in length to the body itself. Gnathopods (sets of grasping claws located near the head) bear small spines, and can have an inflated appearance in older males.

Habitat: Sublittoral (usually) on hydroids or algae. May also be found attached to floating objects such as algae or buoys, so may occasionally be found washed up on shore. Reported to swim at night, although this is rare.

Distribution: Found all around Britain and Ireland.

Similar Species: Caprellids can be difficult to tell apart but close inspection of pereopods distinguish this species from all others found here.

Key Identification Features:

• Caprellid up to 25 mm long with smooth body and rounded head.
• Pereopod 3 and 4 fully developed, with 6 articles or segments.

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

iNaturalist: Phtisica marina at iNaturalist World Species Observations database.

GBIF data for Phtisica marina

WoRMS: Phtisica marina at World Register of Marine Species. Accepted name: Phtisica marina Slabber, 1769. AphiaID: 101864.

Classification: Biota; Animalia; Arthropoda; Crustacea; Multicrustacea; Malacostraca; Eumalacostraca; Peracarida; Amphipoda; Senticaudata; Corophiida; Caprellidira; Caprelloidea; Caprellidae; Phtisicinae; Phtisica