Female: P5 has an oval shape and the genital segment is over 2 times longer than the three postgenital segments. P4 endopodite with conical projection.
Male: Caudal rami shorter than the anal segment. P5 with terminal setae of unequal spines. P4 endopodite with conical projection.
North Pacific, North Atlantic, Arctic Basin, Meditteranean Sea
Found at all depth, but most numerous above 500 m.
Female: The dorsoposterior margin of the third thoracic segment protrudes in dorsal view. Abdomen 1.7 times shorter than the cephalothorax. The genital segment with gonopores anterior to the midregion of the dorsal surface, each one with a setule. Caudal rami with undulate dorsal seta, which reaches midway between outer long terminal and innermost terminal seta.
A1 6-segmented.
A3 3-segmented.
Mx1 flat, bilobed with 2 setae and spine on inner lobe and 4 setae on outer lobe.
Mx2 2-segmented. The 2nd segment extends distally as an elongate claw with 2 rows of setules
Mxp 4-segmented. The terminal segment consists of a long claw with a row of setules on cancave surface and carries a process near the base.
P1-P4 with serrate fringes on spines. Endopodites of P2-P4 with conical progection between the second and terminal spines.
P5 with free oval segment, 2 terminal setae. Seta on body near leg.
P6 probably represented by spatulate setule near gonopores.
Male:
Abdomen about 1.8 times shorter than the cephalothorax. The third thoracic segment lacks dorsal protrusion.
A1 lacks distal seta on the third segment.
Mxp with 2nd segment entended, the inner longitudinal cleft with 2 setae and the posterior expansion rimmed with a row of setules. Claw with a process near base.
P5 not delimited from the 1st abdominal segmented, terminal setae shorter than in female.
P6 probably represented by posterolateral flap on ventral surface of the genital segment.
