Description: This body of this amphipod is laterally compressed with a smooth back, small rostrum and relatively robust gnathopods. It grows up to 8 mm in length. The telson is a rounded and triangular in shape. It has short, chunky antennae that are equal or almost equal in length and no accessory flagellum.

Habitat: Amongst algae from the lower shore to shallow sublittoral.

Distribution: Scattered records from all around Britain and Ireland. Probably under-recorded.

Similar Species: Amphipods can be hard to distinguish in the field as many require microscopic examination and specialist guides. Careful inspection of the key features and a specialist key may be required to reliably distinguish this from other similar species.

Key Identification Features:

• Smooth back.
• Relatively robust gnathopods.
• Rounded, triangular telson.
• No accessory flagellum.

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

iNaturalist: Calliopius laeviusculus at iNaturalist World Species Observations database.

WoRMS: Calliopius laeviusculus at World Register of Marine Species.