Impletosphaeridium conicosum (Jiabo, 1978, p.57, pl.29, figs.4–5) Chen et al., 1988, p.7.

NOW Palaeohystrichodinium. Originally Bipolaribucina, subsequently Impletosphaeridium, thirdly (and now) Palaeohystrichodinium.

Holotype: Jiabo, 1978, pl.29, fig.4.
Age: Early Tertiary.