From Fensome et al., 2019:
Cleistosphaeridium oligacanthum ssp. oligacanthum
Autonym. Holotype: Wetzel, 1952, pl.A, fig.8; Sarjeant, 1984c, pl.2, figs.4–5;
text-fig.2; Fensome et al., 1995, figs.1–5 -- p.1625. Now redundant. Originally Hystrichosphaeridium
oligacanthum subsp. oligacanthum, subsequently Baltisphaeridium oligacanthum subsp. oligacanthum
(Appendix A), thirdly Cleistosphaeridium? oligacanthum subsp. oligacanthum.

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