• Thecadinium Kofoid & Skogsberg, 1928
• Thecadinium acanthium M. Hoppenrath, 2000
• Thecadinium arenarium Yoshimatsu, Toriumi & Dodge, 2004
• Thecadinium aureum P.H. Campbell, 1973 accepted as Pseudothecadinium campbellii Hoppenrath & Selina, 2006
• Thecadinium dragescoi Balech, 1956
• Thecadinium ebriolum Kofoid & Skogsberg, 1928 accepted as Sinophysis ebriolum (E.C. Herdman) Balech, 1956
• Thecadinium ebriolum Schiller, 1933 accepted as Sinophysis ebriolum (E.C. Herdman) Balech, 1956
• Thecadinium foveolatum Bolch, 2004 accepted as Thecadinium yashimaense Yoshimatsu, Toriumi & Dodge, 2004
• Thecadinium hirsutum Balech, 1956 accepted as
• Thecadinium inclinatum Balech, 1956 accepted as Thecadinium semilunatum (Herdman) Dodge, 1982
• Thecadinium kofoidi Schiller, 1933 accepted as Thecadinium petasatum Kofoid & Skogsberg, 1928 accepted as Thecadinium kofoidii (Herdman) Schiller, 1933
• Thecadinium kofoidii (Herdman) J. Larsen, 1985
• Thecadinium kofoidii (Herdman) Schiller, 1933
• Thecadinium mucosum Hoppenrath & Taylor, 2004
• Thecadinium neopetasatum Saunders & Dodge, 1984
• Thecadinium ornatum M. Hoppenrath, 2000
• Thecadinium ovatum Yoshimatsu, Toriumi & Dodge, 2004
• Thecadinium petasarum (Herdman) Kofoid & Skogsberg, 1928 accepted as Thecadinium kofoidii (Herdman) Schiller, 1933
• Thecadinium petasatum Dodge, 1982 accepted as Thecadinium kofoidii (Herdman) Schiller, 1933
• Thecadinium petasatum Kofoid & Skogsberg, 1928 accepted as Thecadinium kofoidii (Herdman) Schiller, 1933
• Thecadinium semilunatum (Herdman) Dodge, 1982
• Thecadinium striatum Yoshimatsu, Toriumi & Dodge, 2004
• Thecadinium swedmarki Balech, 1956 accepted as Amphidiniopsis swedmarkii (Balech, 1956) J.D. Dodge, 1982
• Thecadinium swedmarkii Balech accepted as Amphidiniopsis swedmarkii (Balech, 1956) J.D. Dodge, 1982
• Thecadinium yashimaense Yoshimatsu, Toriumi & Dodge, 2004