Gymnodinium australiense Deflandre and Cookson, 1955

Now Apteodinium. Originally Gymnodinium, subsequently Scriniodinium, thirdly (and now) Apteodinium; see also Emslandia (combination not validly published).
Taxonomic junior synonym: Emslandia crassimurata, according to Lucas-Clark (1987, p.174).

Holotype: Deflandre and Cookson, 1955, pl.5, fig.1.
Locus typicus: Victoria, Australia
Stratum typicum: Middle Miocene

Original description: Deflandre and Cookson, 1955, p.248
Cell globular, divided into two approximately equal parts by a narrow, rather shallow, strongly helicoid girdle. A longitudinal furrow is visible on the hypotheca. The epitheca is surmounded by a short truncate process, the centre of which is frequently depressed. Usually the base of the process is distinctly mammilate. Hypotheca widely rounded; both parts or only the epitheca are bell-shaped. The membrane is finely punctate and sometimes indistinct lines suggestive of plates are apparent. The cell is generally encysted with a more or less quadrangular opening on the dorsal face of the epitheca.
Dimensions: Total length 102-105 Ám, breadth 87-105 Ám.