Prolixosphaeridiopsis spissa (McIntyre and Brideaux, 1980, p.20, pl.7, figs.1–9) Hogg and Bailey, 1997, p.50.

Originally Cleistosphaeridium, subsequently Prolixosphaeridium?, thirdly (and now) Prolixosphaeridiopsis.

Holotype: McIntyre and Brideaux, 1980, pl.7, figs.1–4.
Age: Valanginian.