Can be distinguished by the comparatively slender genital segment (in lateral view) and the long anal segment and caudal rami relative to preceding segments. The cephalothorax of many specimens is abnormally expanded, possibly deformed by internal cystic growth.
Male can be distinguished from similar species O. lacinia and O. oceanica by armature of the swimming legs and distinctive P5.
Bipolar species. Antarctic (Pacific SW), Norwegian Sea, Arctic Ocean
Bathypelagic
Male:
Abdomen about 1.9 times shorter than the cephalothorax. Caudal rami with dorsal seta reaching midway between the inner and outer long terminal setae.
Mxp expanded, 2 setae on inner longitudinal cleft. The posterior and anterior expansions rimmed with rows of setules.
P2 and P3 endopodites end in conical projections between the 2nd and terminal spines, P4 without such projection.
P5 with a small free segment.
P6 probably represented by posterolateral flap on ventral surface of the genital segment.
Female: 0,50-0,60 mm
Male: 0,46-0,56 mm
