Like other members of the Anthuridae, A. gracilis has an elongated body, with the pereon somites being longer than wide. The first pereopods are broad and subchelate, pleon segments 1-5 are fused in females, and the squarish pleotelson has a pair of statocysts. Males 4 mm, females 11 mm.
Distribution and Habitat
Mainly sublittoral, but may be found in the intertidal zone in crevices and Laminaria holdfasts. It has been recorded on southern and western British and Irish Sea shores.
Naylor, E. & A. Brandt. 2015. Intertidal Marine Isopods. Synopses of the British Fauna (New Series), No. 3. Field Studies Council, for The Linnean Society of London.