Eurydinium glomeratum (Davey, 1970) Stover and Evitt, 1978

Originally Deflandrea, subsequently Isabelidinium, thirdly (and now) Eurydinium. See also Isabelia (combination illegitimate).
Holotype: Davey, 1970, pl.1, figs.7-8
Locus typicus: Saskatchewan, Canada
Stratum typicum: Cenomanian

Original description: Davey, 1970, p. 343: Deflandrea glomerata
Cyst smooth-walled, circular in outline with single pointed antapical horn asymmetrically placed. Apical horn absent. Inner body circular in outline and in contact with outer membrane except in apical and antapical regions. Cingulum and sulcus typically absent. Archaeopyle angular, six-sided, with similar shaped opening on inner body.
Dimensions: Holotype: overall length 97 Ám, overall width 70 Ám, length of inner body 72 Ám, width of inner body 69 Ám. Range: overall length 71(82.9)97 Ám, overall width 55(65.9)75 Ám, length of inner body 57(67.3)79 Ám, width of inner body approximately equals overall width. Number of specimens measured, 14.

Original description: Davey, 1970, p. 344: Deflandrea glomerata
These cysts are relatively simple and show little variation. At the apical region of the outer membrane there is typically a small number of concentric wrinkles - perhaps a very rudimentary apical horn. In one specimen a part of the cingulum is indicated by a few aligned granules. It is significant that the inner body possesses a six-sided opening directly beneath the archeopyle in the outer membrane. Both are a reflection of plate 2a in the original dinoflagellate theca.

Affinities:
Davey, 1970, p. 344: Deflandrea glomerata
The circular outline with a simple antapical horn easily differentiates D. glomerata from all previously described species.