From Fensome et al., 2019:
Dinogymnium digitus ssp. crassum (Vozzhennikova, 1967, p.44, pl.5, figs.3,9–10) Lentin and Williams, 1973, p.49. Holotype: Vozzhennikova, 1967, pl.5, fig.9; Lentin and Vozzhennikova, 1990, text-fig.3; lost according to Lentin and Vozzhennikova (1990, p.16). Originally Gymnodinium digitus var. crassum (Appendix B), subsequently (and now) Dinogymnium digitus subsp. crassum. Age: Turonian.

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Translation Vozzhennikova, 1967: Lentin and Vozzhennikova, 1990

Original description: Vozzhennikova, 1967, p. 44: Gymnodinium digitus var. crassus
Theca elongate oval in outline. Epitheca and hypotheca almost equal in size and with their poles broadly rounded. In some examples the epitheca is a little wider than the hypotheca. Transverse furrow annulate, deep, often with a raised margin. Longitudinal furrow slit-like, extending to the pole. Theca pale colored, smooth or covered with a fine longitudinal ribbing.
Size: Holotype, length 49.5 µm, width 14.5 µm.