| Schroederella delicatula (H. Perag.) Pavill., 1913 |
| Shionodiscus A.J. Alverson, S.H. Kang & E.C. Theriot, 2006 |
| Shionodiscus bioculatus (Grunow) A.J. Alverson, S-H. Kang & E.C. Theriot, 2006 |
| Shionodiscus endoseriatus (Hasle & G.A. Fryxell) A.J. Alverson, S-H. Kang & E.C. Theriot, 2006 |
| Shionodiscus gracilis (Karsten) A.J. Alverson, S-H. Kang & E.C. Theriot, 2006 |
| Shionodiscus gracilis var. expectus (VanLandingham) A.J. Alverson, S-H. Kang & E.C. Theriot, 2006 |
| Shionodiscus oestrupii (Ostenf.) A.J. Alverson, S.H. Kang & E.C. Theriot, 2006 |
| Shionodiscus oestrupii var. venrickiae (G.A. Fryxell & G.R. Hasle) A.J. Alverson, S.H. Kang & E.C. Theriot, 2006 |
| Shionodiscus poro-irregulatus (Hasle & Heimdal) A.J. Alverson, S-H. Kang & E.C. Theriot, 2006 |
| Skeletonema Grev., 1865 |
| Skeletonema costatum (Grev.) Cleve, 1873 |
| Skeletonema potamos (C.I.Weber) Hasle, 1976 |
| Skeletonema pseudocostatum L.K.Medlin, 1991 |
| Skeletonema subsalsum (Cleve-Euler) Bethge, 1928 |
| Skeletonema tropicum Cleve, 1900 |
| Stephanodiscus Ehrenb., 1845 |
| Stephanodiscus aegyptiacus Ehrenb., 1854 |
| Stephanodiscus asteroides Gasse, 1980 |
| Stephanodiscus asteroides var. intermedius Gasse, 1980 |
| Stephanodiscus astrea (Ehrenb.) Grunow, 1880 |