Baltisphaeridium longispinosum, (Eisenack, 1931 ex O. Wetzel, 1933), Eisenack, 1959

Originally Hystrichosphaera longispinosa, subsequently Hystrichosphaeridium longispinosum, thirdly (and now) Baltisphaeridium longispinosum; see also Ovum hispidum ssp. Iongispinosum (name not validly published) and Micrhystridium longispinosum (an acritarch species; combination not validly published). Eisenack, 1958 did not validly publish the combination Baltisphaeridium longispinosum since he did not fully reference the basionym.

Holotype: Eisenack, 1931, pl.5, fig.10 (as Ovum hispidum ssp. Iongispinosum); lost, according to Eisenack, 1959
Neotype: Eisenack, 1959, pl.15, fig.1; designated by Eisenack, 1959
Age: Ordovician (based on material from an erratic)