From Fensome et al., 2019:
Circulodinium distinctum ssp. Iongispinatum (Davey, 1978, p.894, pl.3, figs.4,7–8) Lentin and Williams, 1989, p.63. Holotype: Davey, 1978, pl.3, fig.7. Originally Cyclonephelium distinctum subsp. longispinatum, subsequently Circulodinium distinctum subsp. longispinatum, thirdly Cyclonephelium longispinatum. Taxonomic senior synonym: Tenua anaphrissa, according to Fensome et al. (2019a, p.45–46). Age: Turonian.

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Original description as Cyclonephelium distinctum ssp. Iongispinatum: [Davey, 1978, p. 894]:

Diagnosis:
A subspecies of C. distinctum having a denser covering of long spines which extend well on lo the dorsal and ventral surfaces leaving only small areas devoid of processes.

Dimensions:
Type: length of shell (including operculum) 65 µm, width 60 µm, length of processes 8-14 µm.
Range: length of shell (operculum detached) 48-53 µm, width 54-60 µm, length of processes up to 15 µm.