Ovum hispidum ssp. penicillatum (Ehrenberg, 1843b, p.62 ex Ehrenberg, 1854, pl.37, section 8, fig.3) Downie and Sarjeant, 1965, p.174

Now Systematophora. Originally Xanthidium (an extant desmid genus), subsequently Ovum hispidum (combination not validly published), thirdly Hystrichosphaera, fourthly Hystrichosphaeridium, fifthly (and now) Systematophora.
Tax. sr. synonym of Systematophora fasciculigera Klement, 1960, according to Sarjeant, 1980. Stover and Evitt, 1978 considered this species to be a "problematical species" of Hystrichosphaeridium. According to Sarjeant, 1980, this species name was a nomen nudum in Ehrenberg, 1843.

Holotype: Ehrenberg, 1854, pl.37, fig.8.3
Age: Late Oxfordian