From Fensome et al., 2019:
Trithyrodinium ornatum Felix and Burbridge, 1973, p.23–24, pl.4, fig.12.
Holotype: Felix and Burbridge, 1973, pl.4, fig.12.
NOW Ginginodinium. Originally Trithyrodinium, subsequently (and now) Ginginodinium.

Locus typicus: Ellef Ringes Island, Arctic Canada
Stratum typicum: Maastrichtian

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Original description: Felix and Burbridge, 1973, p.23
Overall length of theca 72-84 µm, width 60-69 µm. Girdle width 6-7 µm. Apical horn 7-7.5 µm. in length. Ornamentation of scattered tubercules, variable in arrangement but more usually densely aligned along sutures. Thecal sutures in form of grooves; thecal tubercules about 1µm in diameter and to 1.5 µm in height. Longitudinal furrow not distinguished. Archeopyle formed by removal of three intercalary plates.
Holotype Dimensions: Length of theca 72 µm, width 61 µm.

Affinities:
Felix and Burbridge, 1973, p. 24: The genus was differentiated from Deflandrea by Drugg (1967, p. 20) on the character of the archeopyle, with its three intercalary plates as opposed to the single plate in Deflandrea. The only previously described species, T. evittii, possesses a thin, smooth test as compared to the somewhat
thick and ornamented test of T. ornatum. The Arctic specimens also possess a distinct tabulation with thecal sutures in the form of grooves.