From Fensome et al., 2019:
Impletosphaeridium williamsii (Boltenhagen, 1977, p.41–42, pl.2, figs.6–7) Islam, 1993, p.87. Holotype: Boltenhagen, 1977, pl.2, fig.6;
Fauconnier and Masure, 2004, pl.50, fig.6. Originally Polysphaeridium, subsequently Cleistosphaeridium, thirdly (and now) Impletosphaeridium. Age: Cenomanian–early Turonian.

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