Females: Genital segment with 2 lobes on each side and lobes 2/3 as long as the width of the segment. Caudal rami 3.5-3.6 times longer than wide. Internal projection on P5 with fewer than 8 teeth.
Coast of Alaska, Chukotka coast, Spitzbergen coast, White Sea, Barents Sea (near Novaja Zemlja)
Freshwater/brackish
Female: Head separate from thorax, 4th and 5th segments separate, the back corners of the last thoracic segment in females carry large wing-like growths, and are rounded in males. Rostrum bifurcate with 2 small filaments. Abdomen contains 3 segments. Internal projection of P5 exopodite with fewer than 8 teeth along the distal margin; hair-like microsetules may be present on one or both sides of the projection margin. Genital segment with 2 lobes on each side, maximum lobe length over 2/3 as long as the width of the segment. Caudal rami 3.5-3.6 times longer than wide.
Male: The back corners of the last thoracic segment are rounded, body more slender than in females. A1 geniculate. Abdomen contains 5 segments. Each of the last 2 segments of the right P5 longer than the previous (3rd to last) segment.
Egg-brooding species
Females: 1.20-2.34 mm
Males: 1.10-2.10 mm
