Hystrichosphaeridium palmatum ssp. parvum (Rozen, 1965) Lentin and Williams, 1981

Combination illegitimate, since the species name Hystrichosphaeridium palmatum is illegitimate.
Now Hystrichosphaeridium recurvatum ssp. parvum. Originally Hystrichosphaeridium recurvatum var. parvum, subsequently (and now) Hystrichosphaeridium recurvatum ssp. parvum, thirdly Hystrichosphaeridium palmatum ssp. parvum, fourthly (and now) Hystrichosphaeridium duplum ssp. parvum (name illegitimate).
Lentin and Williams, 1973, raised this variety to the subspecies level, as Hystrichosphaeridium recurvatum ssp. parvum.
Holotype: Rozen, 1965, pl.4, flg.6, text-fig.13
Age: Late Eocene