Body clear and colorless, sometimes opaque. Sometimes a pale red spot is present at the base of A1. Eye bright red.
Posterior corners of the thorax are rounded, head smoothly rounded from side view. Caudal rami equal in length the anal segment, abdomen 1.5 times shorter than the cephalothorax. P5 four-segmented, the distal segment of P5 with 3 apical chaetae. A1 longer than the cephalothorax, but shorter than the body.
Arctic and sub-Arctic, North Atlantic. On the Pacific side reaches the south of the Chukchi sea, is found near the coast of Alaska. In some areas are among the dominating species by abundance and biomass.
Oceanic, epi- to bathypelagic species. Very well pronounced vertical migrations. Males dwell deeper than females.
Female:
The back is only slightly arched. The posterior corners of the last thoracic segment are pulled back, rounded from side view. The genital segment is somewhat shorter than the combined length of the next 2 segments. Caudal rami short, equal in length to the anal segment. Abdomen 1.5 times shorter than the cephalothorax. A1 reach the middle of the middle of the genital segment. P5 four-segmented, the distal segment in thinner than the previous and carries 3 apical chaetae, of which the middle one is the longest. The distal edge of the 2nd and 3rd segments carries a spine facing the outside.
Male:
Body more slender and narrow than in female. The left (rarely right) A1 is geniculate. The distal segments of P5 elongate; a projection is present only on the right leg, the left leg does not carry spines or projections.
Egg-broadcasting species
Female: 1,64-4,50 mm
Male: 1,59-4,00 mm
