Palaeoperidinium hyalodermum

"hyalodermum" Deflandre, 1939b, p.144, pl.6, figs.3-4.  Holotype: Deflandre, 1939b, pl.6, figs.3-4; Jan du Chêne et al., 1986a, pl.58, figs.1-5.  Name not validly published: generic name not validly published until 1967.  NOW Impagidinium?.  Originally Palaeoperidinium (name not validly published), subsequently Gonyaulacysta, thirdly Gonyaulacysta?, fourthly Rhynchodiniopsis?, fifthly (and now) Impagidinium?.  Age: Kimmeridgian.

Parent: Palaeoperidinium