Hystrichosphaeridium geometricum Pastiels 1948
"geometricum" Pastiels, 1948, p.41, pl.4, figs.1–11. Holotype: Pastiels, 1948, pl.4, fig.4. Name illegitimate — senior homonym: Hystrichosphaeridium geometricum Deflandre, 1945a. Substitute name: Apectodinium pastielsii (name illegitimate). NOW Apectodinium geometricum. Originally Hystrichosphaeridium geometricum (name illegitimate), subsequently Baltisphaeridium geometricum (Appendix A), thirdly Apectodinium pastielsii (name illegitimate), fourthly (and now) Apectodinium geometricum. Taxonomic junior synonym (at specific rank): Wetzeliella homomorpha var. quinquelata (as Wetzeliella quinquelata, now Apectodinium quinquelatum), by implication in Harland (1979c, p.67), who considered the latter to be the senior name — however, Lentin and Williams (1989, p.18) retained Apectodinium quinquelatum. Age: Eocene.
Parent: Hystrichosphaeridium