Gymnodinium nelsonense Cookson, 1956, p.183

Now Dinogymnium. Originally Gymnodinium, subsequently (and now) Dinogymnium.
Taxonomic junior synonym: Gymnodinium (as Dinogymnium) hyalinum, according to Lentin and Vozzhennikova (1990, p.21).

Holotype: Cookson, 1956, pl.1, fig.10; Lentin and Vozzhennikova, 1990, pl.2, fig.8
Paratypes: Cookson, 1956
Locus typicus: Nelson Bore, Victoria, Australia
Stratum typicum: Senonian

Original description: Cookson, 1965, p.183
The cell is roughly fusiform with a delicate, finely and faintly granular membrane; usually it is more or less longitudinally folded and at approximately half its length transversely crumpled, so that the nature and even the existence of a transverse girdle is difficult to determine; a slight waist-like narrowing (Plate 1, Fig. 8) delimits a broad "epitheca" with a bluntly rounded apex from a somewhat longer "hypotheca", which gradually narrows towards a rounded or truncate antapex; frequently a small oval opening seems to be present at this end of the cell (Plate 1, Fig. 10).
Dimensions (approximate on account of folding).
Holotype: length 70 µm, width 38 µm.
Paratypes, 120x39 µm, 75x36 µm.