Achomosphaera mariannae, (Philippot, 1949, p. 56-57, text-fig.2), Stover and Evitt, 1978, p. 139.

Originally Hystrichosphaeridium, subsequently Baltisphaeridium (Appendix A), thirdly (and now) Achomosphaera.

Holotype: Philippot, 1949, text-fig.2.
Age: Late Cretaceous.