Similar to O. setosa and O. minuta, but may be distinguished by:
- differences in the relative cephalothorax/abdomen lengths – the abdomen being more than ½ of cephalothorax in O. lacinia, and about ½ in O. setosa,
- lack of a cluster of spinutes on 2nd segment of A2
- relatively long spinule of female P6
- unsegmented P5
Bipolar species. Antarctic (Pacific SW), Arctic, Norwegian Sea, Washington Inland, Sea of Japan
Epipelagic
Female:
Abdomen about 1.8 times shorter than the cephalothorax. Genital segment with gonopores immediately anterior to midregion of the dorsl surface, each area with a setule. Dorsal seta of caudal ramus extends to more than twice the length of the innermost terminal seta, which is shorter than the length of the caudal ramus. P2 and P3 endopodites end in conical projections between the 2nd and terminal spines, P4 without such projection. P5 small, not delimited form the 1st abdominal segment and with dorsal pointed process and 2 terminal setae, of which the inner is about 2 times shorter than the longer one.
P6 probably represented by relatively long, spiniform near area of external genital apparatus.
Male:
Abdomen about 2 times shorter than cephalothorax. A1 lacks a distal seta on third segment. Anterior expansion of Mxp produced as hyaline flap fringed with setules. P6 probably represented by posterolateral flap on ventral surface of genital segment.
Female: 0,42-0,48 mm
Male: 0,36-0,46 mm
