Palaeoperidinium "nudum" Nagy, 1969, p.291, pl.1, fig.1.

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 Pyxidinopsis? pannonia (name illegitimate), eighthly (and now) Pyxidinopsis? nuda.
Nomenclatural junior synonym: Palaeoperidinium (subsequently Phthanoperidinium, Tectatodinium? and Pyxidinopsis?) pannonium, which has the same type. See also the discussion under Pyxidinopsis? nuda and Palaeoperidinium nudum Downie 1957.

Holotype: Nagy, 1969, pl.1, fig.1.
Age: late Miocene.