From Fensome et al., 2019:
Cleistosphaeridium tenue Harris, 1974, p.164, pl.2, figs.7–9. Holotype: Harris, 1974, pl.2, figs.8–9. NOW Sepispinula?. Originally Cleistosphaeridium, subsequently Impletosphaeridium, thirdly (and now) Sepispinula?. Age: Paleocene.

---------------------------------------------------------------------------------------------------