Hystrichosphaeridium bulbosum (Ehrenberg, 1838) Deflandre, 1937; Emendation: Morgenroth, 1968, p.46-47, as Hystrichokolpoma bulbosum.

NOW Hystrichokolpoma bulbosum. Originally Xanthidium bulbosum, subsequently Hystrichosphaera bulbosa (combination not validly published), thirdly Hystrichosphaeridium bulbosum, fourthly Ovum hispidum subsp. bulbosum (combination not validly published), fifthly (and now) Hystrichokolpoma bulbosum, sixthly Baltisphaeridium bulbosum (combination not validly published).
Taxonomic senior synonym: Xanthidium (as Hystrichosphaeridium) tubiferum, according to Stover and Evitt (1978, p.55) - however, Lentin and Williams (1981, p.134) retained Hystrichosphaeridium (as Hystrichokolpoma) bulbosum.

Holotype: Ehrenberg, 1838, pl.1, fig.17
Neotype: Morgenroth, 1968, pl.44, fig.6, designated by Morgenroth (1968, p.546)
Age: Danian