From Fensome et al., 2019:
Impletosphaeridium tenuifilum (Cookson and Eisenack, 1982, p.40, pl.8, fig.14) Islam, 1993, p.87. Holotype: Cookson and Eisenack,
1982, pl.8, fig.14. Originally Cleistosphaeridium, subsequently (and now) Impletosphaeridium?. Questionable assignment: Islam (1993, p.87). Age: Paleocene.

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