(from Hendrycks & Bousfield 2004 with additions)
1 Pleon segment 3 with strong dorsal process; propodus of pereopod 2 (gnathopod 2) with shallow notch on the palmar margin; basis of pereopod 5 narrow, not broadened as in pereopod 7 (figs. 1k, 5i).................. S. gagarae (Gurjanova, 1972)
– Pleon segment 3 with small middorsal knob; propodus of pereopod 2 (gnathopod 2) with deep notch on the palmar margin; basis of pereopod 5 rounded behind (figs. 1j, 5i).................................... S. cornigerus (Shoemaker, 1964)