(Modified from Salazar-Vallejo & Buzhinskaja 2011)
1 Body tunic without sand particles, or with a few sand and fine particles.......................................... 2
– Body tunic with sand particles; median chaetigers with 7–8 notochaetae per bundle; neurochaetae with long articles distally.................................................................................................... 7
2(1) Median chaetigers with notochaetae as long as body width; papillae very long, single; neurochaetal tips falcate (body often reddish)................................................. S. hirsuta (Hansen, 1882)n. comb. Arctic and subarctic
– Median chaetigers with notochaetae longer than body width................................................... 3
3(2) Median neurochaetae with distal articles barely longer than wide, tips straight; gonopodial lobes present................ 4
– Median neurochaetae with most articles markedly longer than wide; no gonopodial lobes............................ 5
4(3) Gonopodial lobes dark (papillae core and tip blackish); body papillae thick, digitate (body often grayish)..................................................................... S. normani (McIntosh, 1908)n. comb. Arctic and subarctic
– Gonopodial lobes pale; body papillae thin, filiform (body often pale)..................................................................................................... S. longisetosa (von Marenzeller, 1890) Gulf of Alaska
5(3) Median chaetigers with neurochaetal tips falcate............................................................. 6
– Median chaetigers with neurochaetal tips straight, non-falcate.................. S. omorpha n. sp. Central eastern Pacific
6(5) Median chaetigers neurochaetae with basal anchylosed region 1/2–1/3 chaetal length, medial and distal regions with articles 4–5 times longer than wide, barely shorter with a very slight reduction distally......... S. ilys n. sp. Central eastern Pacific
– Median chaetigers neurochaetae with basal anchylosed region 1/5–1/6 chaetal length, medial and distal regions with articles about twice longer than wide, progressively smaller.......... S. micans (Fauchald, 1972)n. comb. Central eastern Pacific
7(1) Neurochaetal tips falcate............................................................................... 8
– Neurochaetal tips straight............................................................................... 9
8(7) Median chaetigers with notochaetae half as long as body width; median neuropodia with five neurochaetae per bundle; body wall and chaetae yellowish...................................... S. acafi (Teixeira, Rizzo & Santos, 2015)n. comb.
– Median chaetigers with notochaetae slightly longer than body width; median neuropodia with eight neurochaetae per bundle; body wall and chaetae cinnamon in colour................................... S. canela n. sp. Central eastern Pacific
9(7) Sand particles restricted to the bases of papillae; neurochaetae with anchylosed region about 1/5 chaetal length........................................................... S. octobranchia (Hartman, 1965)n. comb.Northwestern Atlantic
– Sand particles fixed along the papillae; neurochaetae with anchylosed region 1/2–1/3 chaetal length................................................................................................. Saphobranchia sp. Antarctica