Pyxidinopsis ?nuda (Nagy, 1969, p.291, pl.1, fig.1) Williams et al., 1998, p.520–521.

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. Questionable assignment: Head (1994a, p.308), for Pyxidinopsis? pannonia.
Nomenclatural junior synonym: Palaeoperidinium (subsequently Phthanoperidinium, Tectatodinium? and Pyxidinopsis?) pannonium, which has the same type.
Lentin and Williams (1973, p.106) proposed the name Palaeoperidinium pannonium for Palaeoperidinium nudum Nagy in the belief that the latter was an illegitimate junior homonym of Palaeoperidinium nudum Downie. However, Williams et al. (1998, p.521) re-interpreted Palaeoperidinium nudum Downie to be an invalid name; thus, Palaeoperidinium nudum Nagy must be considered as a validly published and legitimate name. In light of this, Williams et al. (1998, p.520–521) proposed the combination Pyxidinopsis? nuda.

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