Female:
A1 longer than the body, caudal rami longer than the anal segment. The chaetae on the distal segment of P5 point in the direction of the long axis of the leg and are located on the tip of the segment.
Male:
the distal segment of the right P5 separated with a parallel plate. A1 longer than the body, caudal rami significantly longer than the anal segment.
North and temperate Atlantic, Antarctic, south-west Pacific Ocean. According to Markhaseva (2001) : probably the distributional range for this species is not so wide, as it could have been mixed with other large-sized Metridia, the taxonomic status of which are not clear.
Oceanic, bathypelagic species. Occurs at depths no less than 1000 m.
Female:
Rostrum has the shape of a split plate, which carries 2 plumose filaments of moderate length. The posterior corners of the last thoracic segment are very short and rounded. Abdomen very long, almost as long as the cephalothorax. The anal segment is widened with outstanding corners. The genital segment is longer than the next 2 segments combined. The anal segment is half as long as the previous segment. The caudal rami are twice as long as the anal segment and more than 5 times longer than wide. A1 longer than the body. Denticles on the 1st segment of the endopodite of A1 are very prominent. P5 four-segmented (3 free segments), the first segment carries a group of long chaetae on the outer edge, the distal segment carries 3 plumose chaetae of almost equal length. The second to last segment carries a spine on the distal edge.
Male:
The left A1 is genicaulate. The right P5 is 4-segmented, the inner projection on the second segment is long and slightly curved, the distal segment carries a parallel plate, which is separated from the segment. The left P5 is shorter, without spines on the inner edge of the 2nd segment; the last 2 segments are fused.
Female: 6,69-9,00 mm
Male: 5,80-8,50 mm
