• Thecadinium Kofoid & Skogsberg, 1928
• Thecadinium acanthium Hoppenrath, 2000
• Thecadinium arenarium S.Yoshimatsu, S.Toriumi & J.D.Dodge, 2004
• Thecadinium aureum P.H.Campbell, 1973 accepted as Pseudothecadinium campbellii Hoppenrath & M.Selina, 2006
• Thecadinium dragescoi Balech, 1956 accepted as Amphidiniopsis dragescoi (Balech) Hoppenrath, Selina, Yamaguchi & Leander, 2012
• Thecadinium ebriolum (Herdman) Kofoid & Skogsberg, 1928 accepted as Sinophysis ebriola (Herdman) Balech, 1956
• Thecadinium foveolatum Bolch, 2004 accepted as Thecadinium yashimaense S.Yoshimatsu, S.Toriumi & J.D.Dodge, 2004
• Thecadinium hirsutum Balech, 1956 accepted as Amphidiniopsis hirsuta (Balech) J.D.Dodge, 1982
• Thecadinium inclinatum Balech, 1956
• Thecadinium kofoidii (Herdman) J.Schiller, 1931
• Thecadinium mucosum Hoppenrath & Taylor, 2004 accepted as Thecadinium yashimaense S.Yoshimatsu, S.Toriumi & J.D.Dodge, 2004
• Thecadinium neopetasatum R.D.Saunders & J.D.Dodge, 1984
• Thecadinium ornatum Hoppenrath, 2000
• Thecadinium ovatum S.Yoshimatsu, S.Toriumi & J.D.Dodge, 2004
• Thecadinium petasarum (Herdman) Kofoid & Skogsberg, 1928 accepted as Thecadinium kofoidii (Herdman) J.Schiller, 1931
• Thecadinium petasatum Dodge, 1982 accepted as Thecadinium kofoidii (Herdman) J.Schiller, 1931
• Thecadinium petasatum Kofoid & Skogsberg, 1928 accepted as Thecadinium kofoidii (Herdman) J.Schiller, 1931
• Thecadinium pseudokofoidii Selina, Efimova & Hoppenrath, 2019
• Thecadinium semilunatum (Herdman) J.D.Dodge, 1982 accepted as Ankistrodinium semilunatum (Herdman) Hoppenrath, Shauna Murray, Sparmann & Leander, 2012
• Thecadinium striatum S.Yoshimatsu, S.Toriumi & J.D.Dodge, 2004
• Thecadinium swedmarkii Balech, 1956 accepted as Amphidiniopsis swedmarkii (Balech) J.D.Dodge, 1982
• Thecadinium yashimaense S.Yoshimatsu, S.Toriumi & J.D.Dodge, 2004