Xanthidium bulbosum Ehrenberg, 1838

Now Hystrichokolpoma. Originally Xanthidium, subsequently Hystrichosphaera, thirdly Hystrichosphaeridium, fourthly (and now) Hystrichokolpoma; see also Ovum hispidum (name not validly published) and Baltisphaeridium (an acritarch genus; combination not validly published).
Tax. jr. synonym of Hystrichosphaeridium tubiferum (Ehrenberg, 1838) Deflandre, 1937, according to Stover and Evitt, 1978; however, Lentin and Williams, 1989 retained Xanthidium (as Hystrichokolpoma) bulbosum as a separate species.
Holotype: Ehrenberg, 1838, pl.1, fig.17
Age: Danian