Bradyidius similis (Sars G. O. 1902)

Females:
Rostral rami divergent, but less distinctly with an acute angle at their base. Posterior corners of the last thoracic do not reach the end of the genital segment and are non-divergent.

Arctic and boreal waters of the North Atlantic. Bering and Okhotsk Seas, Gulf of St. Lawrence

Neritic, hyperbenthic, mesopelagic.

Most likely, a year-long cycle. The presence of young copepodites from May-October indicates an extended breeding period, most likely starting before May. By October, young stages dominate in the population.

Female:
Body elongate and oval, anterior profile smoothly rounded. Rostrum chitinized, bifurcate, and slightly divergent. Head and first thoracic segment partially fused, fourth and fifth segments completely fused. Posterior corners of the last thoracic segment have a wide base, are directed in the posterior direction and reach beyond the center of the genital segment. Caudal rami longer than the last abdominal segment. A1 24-segmented, reaches beyond the posterior margin of the third thoracic segment. P5 absent.

Male:
General profile of body similar to that of female, but slightly narrower. First thoracic segment completely fused with the head. Posterior corners of the last thoracic segment weaker than in female and are slightly curved inward, reaching the posterior margin of the first abdominal segment. Ratio of cephalothorax to abdomen is 2.4:1. Abdomen narrow, symmetrical and 5-segmented, the last of which is very short. Caudal rami about 2 times as long as the last thoracic segment. P5 asymmetrical and biramous. Left leg with two-segmented protopod, the second segment is slightly longer than the first. The first segment of the exopod is 1.5 longer than the protopod and twice as long as the second segment, which is sickle-shaped with a medial expansion on medial margin, distal end rounded. Endopod 1-segmented, straight and elongate. Right leg shorter than the left, exopod three-segmented, the distal segment is short and narrow, with a medial expansion near rounded distal end.

Female: 2,84-3,24 mm
Male: 2,40-2,77 mm

Opprotunistic omnivores

Gulf of St. Lawrence (unspecified region), Saguenay Fjord, southern Gaspe waters (Baie des Chaleurs, Gaspe Bay to American, Orphan and Bradelle banks; eastern boundary: Eastern Bradelle Valley), lower St. Lawrence estuary; Prince Edward Island (from the northern tip of Miscou Island, N.B. to Cape Breton Island south of Cheticamp, including the Northumberland Strait and Georges Bay to the Canso Strait causeway)

upper and glacial epipelagic regions of the Gulf and estuary