Litosphaeridium? inversibuccinum Davey and Williams, 1966b, p.82, pl.12, fig.3. Emendation: Bujak et al., 1980, p.32, as Paucisphaeridium inversibuccinum.

Now Paucisphaeridium. Originally Litosphaeridium?, subsequently (and now) Paucisphaeridium.
Davey and Williams, 1966, questionably included this species in Litosphaeridium.

Holotype: Davey and Williams, 1966b, pl.12, fig.3; Eisenack and Kjellström, 1972, p.781; Bujak et al., 1980, pl.2, figs.4–5; Fensome et al., 1995, p.1567; Fauconnier and Masure, pl.63, fig.1.
Locus typicus: Enbourne, Berkshire, England
Stratum typicum: Early Eocene

Original diagnosis: Davey and Williams, 1966, p. 82
Sub-sphaerical or ovoidal central body, not exceeding 20 µm in diameter, with sub-conical processes. Processes open distally, with denticulate or aculate margin. Archaeopyle apical.

Original description: Davey and Williams, 1966, p. 82
The wall of the central body is usually thin, but thick walled specimens have occasionally been encounted. The processes are not in connection with the interior of the central body and seldom extent 15. The larger processes are sub-conical and may be up to 10 µm wide at the base, rapidly decreasing in width to approximatly 1,5-2 µm, before expanding distally into a denticulate or aculeate margin. In addition to these stout processes there are usually one or two slender ones which are possibly closed distallt. The latter are probably sulcal processes. An apical tetragonal archaeopyle was seen in one specimen, the archaeopyle beeing surrounded by by 6 precingular processes. However the remaining tabulation is obscure.