From Fensome et al., 2019:
Palaeohystrichodinium conicosum (Jiabo, 1978, p.57, pl.29, figs.4–5) He Chengquan et al., 2009, p.531. Holotype: Jiabo, 1978, pl.29, fig.4. Originally Bipolaribucina, subsequently Impletosphaeridium, thirdly (and now) Palaeohystrichodinium. Age: early Tertiary.

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Original description (Jiabo, 1978):