Baltisphaeridium bulbosum, (Ehrenberg, 1838), Lentin and Williams, 1973

Combination not validly published, since Lentin and Williams, 1973 did not fully reference the basionym.
Now Hystrichoholpoma. Originally Xanthidium (an extant desmid genus), subsequently Hystrichosphaera, thirdly Hystrichosphaeridium, fourthly (and now) Hystrichokolpoma, fifthly Baltisphaeridium (combination not validly published); see also Ovum hispidum (combination not validly published). This combination cannot be legitimized since it would create a jr. homonym of Baltisphaeridium bulbosum Kjellstr÷m, 1971

Holotype: Ehrenberg, 1838, pl.1, fig.17
Age: Danian