From Fensome et al., 2019:
Apteodinium micracanthum Cookson and Eisenack, 1974, p.51–52, pl.25, figs.2–3. Holotype: Cookson and Eisenack, 1974, pl.25, fig.3. Originally Apteodinium, subsequently (and now) Apteodinium?. Questionable assignment: Stover and
Evitt (1978, p.142), as a problematic species. Age: Albian–Senonian.

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Original description: [Cookson and Eisenack, 1974, p. 51]: (Translation: LPP):

Description:
Outline of shell nearly spherical, epitract slightly pointed with conical to cylindrical sharply delimited apical horn ending with a slit-like indention. Shell covered with a few relatively long and solid, thorn-like processes. Girdle indicated by rows of thorns.
Archaeopyle wide but low.

Dimensions:
Shell c. 70x74 µm, apical horn c.4 µm, length of processes 1-2 µm.