Hystrichosphaera tubifera (Ehrenberg, 1838) O.Wetzel, 1933, p.40; Emendation: Davey and Williams, 1966b, p.56–58, as Hystrichosphaeridium tubiferum.

Combination not validly published: generic name not validly published until 1937.
NOW Hystrichosphaeridium tubiferum. Originally Xanthidium tubiferum (acritarch), subsequently Hystrichosphaera tubifera (combination not validly published), thirdly (and now) Hystrichosphaeridium tubiferum, fourthly Ovum hispidum tubiferum (combination not validly published; acritarch).
Taxonomic junior synonym: Xanthidium (as Hystrichokolpoma) bulbosum, according to Stover and Evitt (1978, p.55) — however, Lentin and Williams (1989, p.134) retained Xanthidium (as Hystrichokolpoma) bulbosum.

Holotype: Ehrenberg 1838, pl.1, fig.16
Locus typicus: Delitzsch flint
Stratum typicum: ?Late Cretaceous
Translations Wetzel, 1933: LPP

Original diagnosis: ?Ehrenberg, 1838: Xanthidium tubiferum

Diagnosis: O. Wetzel, 1933, p. 40
Shell spherical, 10-20 processes, mostly large and strong, tubiform, distally widened into a crown or saucer (comparable to the funnel or mouthpiece of a trumpet). Individual processes may be less strong and distally ornamented with only a few teeth.
Dimensions: diameter of shell 36-40 µm, with processes 64-72 µm, processes 16-20 µm.