| Thalassiothrix Cleve & Grunow, 1880 |
| Thalassiothrix acuta G. Karst., 1906 |
| Thalassiothrix delicatula Cupp, 1943 |
| Thalassiothrix frauenfeldii (Grunow) Grunow, 1880 |
| Thalassiothrix heteromorpha G. Karst., 1907 |
| Thalassiothrix heteromorpha var. mediterranea (Pavill.) Hallegr., 1986 |
| Thalassiothrix longissima Cleve & Grunow, 1880 |
| Thalassiothrix mediterranea Pavill., 1916 |
| Thalassiothrix nitzschioides (Grunow) Grunow, 1881 |
| Thalassiothrix pseudonitzschioides G. Schuette & H.J. Schrad., 1982 |