Clear with red pigment present in lipid stores.
Females: head carries a crest, the distal segment of P5 with 1 inner chaeta, 1 (rather than 2) apical spines and a lateral spine
Males: Endopodite in the left P5 much longer than the exopodite - does not reach the distal end if the first segment in the exopodite. The endopodite is non-segmented.
Cosmopolitan species, occurs in most sub-tropical, temperate, and polar regions in both hemispheres.
Oceanic, bathypelagic species. In Arctic and Antarctic waters is found both at great depths and at the surface, in temperate and tropical waters at depths greater than 1000 m.
Female:
Head with a protruding tip and a well-defined tall median crest. Bifurcate rostrum is composed of 2 long and slender filaments, separated at the very base. 4th and 5th thoracic segments are fused and back corners of the last segment carry blunt rounded points. Abdomen 3.5 times shorter than the cephalothorax. Genital segment only slightly longer than the 2nd abdominal segment, which in turn is slightly longer than the 3rd; the anal segment is very short. The first three abdominal segments carry fine serrations on the distal margin. The genital protuberance has a double tip and does not extend far on the ventral surface. Caudal rami are 1-1.7 times as long as wide. A1 22-segmented and reaches the distal margin of the genital segment. Exopod of A2 is about 1/3 shorter than the endopodite. Mxp1 with worm-like and bud-like filaments. P5 3-segmented, the last two segments being partially fused ; the terminal segment bears 1 very long spine on the inner border, 1 rather short spine on the outer border directly opposite the inner spine, and a 3rd spine, which is intermediate in length, apically ; the outer spine is naked, while the other two are finely plumose. P5 rather small, and when attached to the animal scarcely reach beyond the middle of the urosome.
Male:
Head has a rounded top, without median crest. Back corners of the last thoracic segment rounded with very short tips. Rostral filaments slender and a small fused base. A1 slightly shorter than the cephalothorax. The exopodite of the right P5 with a elongate distal segment, on which the top is split somewhat split. The distal segments of both the exo- and the endopodite of the left P5 short, the exopodite carries 2 curved chaetae and plumage on the inner edge. The endopodite is sharp, non-segmented.
The species shows a certain variability
Broadcast spawners (release eggs freely into the water), sometimes as few as 1 or 2 very large eggs per spawning event (but usually 4-12 eggs). Females release eggs at 1-4 day intervals (in the Arctic Basin).
Females: 3,55-5,60 mm
Males: 4,02-5,28 mm
Omnivores; predominantly feed on detrital particles
