Body clear with a whitish tint
Back is more arched than in M. longa. The greatest height of the head (from side view) is somewhat farther down than the the tip of the head, so that the head is somewhat rounded (less angular than M. pacifica). P5 three-segmented, the inner chaeta on the distal segment of P5 is longer than the other 2.
The caudal rami in males are the same length as the anal segment; the left P5 contains one inner spine.
Barents Sea, Norwegian Sea, North Sea, North and temperate Atlantic, Mediterranean Sea
Oceanic, epi- to bathypelagic species.
The back is arched from side view. The posterior corners of the last thoracic segment with small sharp points, which are visible both from dorsal and side view. Abdomen almost 2 times shorter than the cephalothorax. The genital segment is approximately the same length as the next 2 segments combined. The anal segment is somewhat shorter than the caudal rami. P5 three-segmented, the distal segment carries 3 cheatae, of which the middle one is visibly longer. This segment and also the 2nd segment each carries a long spine on its outer edge.
The distal segment of the right P5 is larger than the left and does not narrow distally. The left P5 with 1 large spine on the inner edge of the 4th segment. The right leg is 4-segmented.