Operculodinium placitum

?placitum Drugg and Loeblich Jr., 1967, p.186, pl.1, figs.9-10,11a-b; text-fig.4.  Holotype: Drugg and Loeblich Jr., 1967, pl.1, figs.11a-b.  Originally Operculodinium, subsequently Operculodinium?.  Questionable assignment: Stover and Evitt (1978, p.179) as a problematic species.  Taxonomic junior synonym: Polysphaeridium cephalum, according to Jain and Garg (1991, p.81).  Age: Late Eocene-Oligocene.

Parent: Operculodinium