• Kingdom: Animalia
  • Phylum: Arthropoda
  • Subphylum: Crustacea
  • Class: Malacostraca
  • Subclass: Eumalacostraca
  • Superorder: Peracarida
  • Order: Isopoda
  • Suborder: Valvifera
  • Family: Arcturidae
  • Scientific name: Astacilla longicornis
  • Norwegian: pinnekreps


It is recognized by the very long antennas, and the long back segment. The legs are attached to the front and back segments. The females can reach a length of 3 cm, the males rarely exceed 1 cm. The segment plates are smooth, without any prickles, in contrast to the four other members of this family, found in Norwegian waters.


This isopod lives on depths between 10 and 100 meters. If is often seen climbing in soft corals and sea pens where it filters water and catches food.


It is registered along the European coasts, from northern Norway to Portugal.