Female:
Last thoracic segment is very small, its posterior corners are not transformed into lobes. The thoracic segments 1-4 are evenly covered with spines on the right and left sides. Body has an elongate-oval shape with narrow wing-shaped folds on the sides of the head (but less pronounced than in S. longispinus or S. pteronus). Abdomen almost as long as wide. The second segment of endopodite of P2 with 1 outer spine.
Antarctic, Gulf of Mexico, Greenland Sea, South China Sea, Sea of Japan, Arctic Basin, off British Columbia
Oceanic, meso- to abyssopelagic species
Female: Cephalothorax has an oval shape from dorsal view, rounded at the front. From side view the back is arched, sharply narrowing toward the head. The side of the head has a narrow clear fold, most visible from dorsal view. Head and 1st thoracic segment partially fused, 4th and 5th completely separate. The corners of the last are widely rounded. The lateral surfaces of thoracic segments 1-4 are densely covered with spines, both on the left and on the right. Abdomen is 2.5-3 times shorter than the cephalothorax. The ventral projection on the genital segment is massive, smoothly curved, about 0.3 times as thick as the next segment. The plate on the genital field is almost as long as wide and makes up less than half of the width of the segment. Spermathecs rounded. The back edges of the abdominal segments are covered with spines. Caudal rami symmetrical, somewhat longer than wide, with transverse row of hairs in the middle of the dorsal side.
A1 longer than the body by 3-4 last segments.
Mxp with a transverse crest of spines on the outer edges of the protopodite and 1st segment of the endopodite.
The distal segment of the exopodite of P1 carries a group of spines on its dorsal surface, the outer spines of the 2nd and 3rd segment are almost equal in length.
The dorsal surface of the coxopodite of P2-P4 is densely covered with hairs, especially P4, with 3-4 rows of spines near the outer edge. The 2nd segment of the endopodite of P2 and the 3rd segment of the exopodite carry 2 rows of spines on the dorsal surface; the 2nd segment of the exopodite – with one row.
P3-P4 armed in a similar way: the 2nd and 3rd segments of the endopodite carry 2 rows of long spines, the 3rd segment of the exopodite – 3 rows of spines. The 2nd segment of the exopodite carries proximally a diagonal row of long slightly flattened spines and a distal row of short spines.
