Palaeoperidinium "pannonium" Lentin and Williams, 1973, p.106.

Holotype: Nagy, 1969, pl.1, fig.1. Name illegitimate — nomenclatural senior synonym: Palaeoperidinium (now Pyxidinopsis?) nudum Nagy, which has the same type.

NOW Pyxidinopsis? nuda. Originally Palaeoperidinium nudum Nagy, subsequently Palaeoperidinium pannonium (name illegitimate), thirdly Phthanoperidinium pannonium (name illegitimate), fourthly Gonyaulacysta? nuda, fifthly Tectatodinium? nudum, sixthly Tectatodinium? pannonium (name illegitimate), seventhly Pyxidiniopsis? pannonia (name illegitimate), eighthly (and now) Pyxidinopsis? nuda. See also the discussion under Pyxidinopsis? nuda.

Age: late Miocene