Chiridius obtusifrons G. O. Sars, 1902
Endopodite of P2 one-segmented. Abdomen longer than 1/3 of cephalothorax. Posterior corners of the last thoracic segment short, divergent. Spermatheca much smaller than in other species of the genus. Male with uniramous P5, the right is longer than the left.
Female: Cephalothorax with widened front third, head fused with thorax, rounded from side view. Posterior corners of the last thoracic segment short, divergent, end before the middle of genital segment. Abdomen is 2.3-2 times shorter cephalothorax, the genital segment is slightly shorter than the combined length of the next 2 segments. Ventral projection very slight. The back edges of the first three segments with serrations. A1 reach the middle of the second abdominal segment. Endopodite of A2 almost 2 times shorter than the exopodite. The outer edge of the second basipodite of P1 with a small spine. Posterior corners of the last thoracic segment. Apical spines of exopodites of P1-P4 coarsely and sharply serrated.
Male: Smaller than female. P5 with no signs of endopodites, each leg five-segmented. A1 about as long as the cephalothorax.
Female: 3,50-4,60 mm
Male: 2,90-3,3 mm
Ecology and Distribution
Arctic species. Central Arctic Basin, North Sea, Norwegian Sea, Barents Sea, Laptev Sea, Greenland Sea, Chukchi Sea, Beaufort Sea, Gulf of Maine
Oceanic, epi-meso-bathypelagic species. In polar water found at small depths and near the surface, in lower latitudes at depths of 200-800 m.
Produce egg-sacs with a thick enclosing membrane, which contains 25-50 bright orange eggs.
Opprotunistic omnivores; mainly feed phytoplankton and/or phytodetritus, but may also consume microzooplankton and copepod nauplii