Ascodinium trendallii, Cookson and Eisenack, 1970; Emendation: Pavlishina, 1995, p.138-139, as Trithyrodinium trendallii.

NOW Trithyrodinium. Originally Ascodinium?, subsequently Subtilisphaera?, thirdly (and now) Trithyrodinium. Questionable assignment: Cookson and Eisenack (1970a, p.145).

Holotype: Cookson and Eisenack, 1970, pl.12, fig.5
Locus typicus: Madura No. 1 Bore, Eucla Basin, Western Australia
Stratum typicum: Albian-Cenomanian

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Original description: [Cookson and Eisenack, 1970, p.145]:

Description:
Shell distinctly longer than broad, rather thin-walled, untabulated and very finely and inconspicuously dotted, with a bluntly pointed median apical projection and a downwardly slanting antapex with a short + sharply pointed projection on the right-hand side. A well-developed subequatorial girdle delimits a longer epitheca from a shorter hypotheca, its ends on the ventral surface being widely separated.
The internal capsule, which is distinctly oval in shape and relatively large, extends to the outer wall of the hypotheca but not quite to that of the epitheca. Its wall appears to be somewhat thicker than that of the shell. On the ventral surface of the hypotheca, between the ends of the girdle, the longitudinal wavy thickening, probably associated with the flagellum pore, is usually prominent.
An archeopyle has not been observed.

Dimensions:
Holotype: Overall length c. 70 µm, overall width 35 µm, internal capsule c. 38x30 µm.
Range: length c. 67-93 µm, breadth c. 33-50 µm.