From Fensome et al., 2019:
Hystrichodinium patriciae (Neale and Sarjeant, 1962, p.451–452, pl.19, fig.3; text-fig.7) Lentin and Williams, 1975, p.2151. Holotype: Neale and Sarjeant, 1962, pl.19, fig.3; text-fig.7. Originally Heliodinium, subsequently (and now) Hystrichodinium. Backhouse (1988, p.92) considered Hystrichodinium oligacanthum to be a possible taxonomic junior synonym of this species. Age: Hauterivian.

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Paratype: Neale and Sarjeant, 1962
Locus typicus: Speeton Clay, Heslerton, England


Original diagnosis: Neale and Sarjeant, 1962, p. 451: Heliodinium patriciae
A species of Heliodinium having an oval theca, with a well-marked transverse furrow dividing it into two Unequal halves. From the crests delimiting plates arise long spines, flat and ribbon-like, tapering gradually to closed points; the length of the spines exceeds the long diameter of the shell. Longitudinal furrow apparently present; detail of tabulation not determined.

Original description: Neale and Sarjeant, 1962, p. 451: Heliodinium patriciae
Theca yellowish, thick-walled, not or only very minutely granular. Transverse furrow of moderate breadth, dividing the theca into two unequal parts, one of which (?epitheca) is a half oval, the other a hemisphere. The ribbon-like spines are very flexible and much folded; they form a tangled mass around the theca which prevents determination of the tabulation.
Dimensions: Overall length 125 µm, breadth 97 µm. Shell length 43.5 µm, breadth 40.5 µm.