Baltisphaeridium tiara, (Klumpp, 1953), Downie and Sarjeant, 1965

Now Operculodinium. Originally Hystrichosphaeridium, subsequently Baltisphaeridium, thirdly Cordosphaeridium, fourthly Cleistosphaeridium, fifthly (and now) Operculodinium. This combination was not validly published in Downie and Sarjeant, 1963 since these authors did not fully reference the basionym.

Holotype: Klumpp, 1953, pl.17, figs.8-9
Age: Eocene