Isabelidinium acuminatum (Cookson and Eisenack, 1958) Stover and Evitt, 1978

Originally Deflandrea, subsequently Alterbia (combination illegitimate), thirdly Senegalinium, fourthly (and now) Isabelidinium.

Holotype: Cookson and Eisenack, 1958, pl.4, fig.5
Locus typicus: Wapet"s Rough Range Well No. 8, W Australia
Stratum typicum: Cenomanian-Early Turoniuan

Original description: Cookson and Eisenack, 1958, p. 27: Deflandrea acuminata
Description: Theca broadly oval with convex sides or almost spherical, apex acuminate, antapex obliquely truncate, prolonged on one side into a small pointed horn. A transverse girdle is perceptible at the lateral margins of the theca. The capsule, which is always separated from the membrane of theca by a relatively wide space is approximately spherical, and slightly pointed on the side directed towards the apex of the theca. Both the internal and external membranes are smooth. A rounded or polygonal pylome is present above the apex of the capsule.
Dimensions: Range: theca 66-99 x 52-62 Ám; capsule 38-47 x 38-47 Ám.