Pervosphaeridium brevispinum (Norvick in Norvick and Burger, 1976) Below, 1982

Originally Exochosphaeridium, subsequently Exochosphaeridium?, thirdly (and now) Pervosphaeridium.

Holotypus: Norvick and Burger, 1976, pl.4, figs.5-6
Locus typicus: Bathurst Island no. 2 well, Australia
Stratum typicum: Cenomanian

Original diagnosis: Norvick, 1976, p.53: Exochosphaeridium brevispinum
Cyst chorate. Central body spherical. Processes short and numerous, three or more per plate area, arrangement random. Processes tapering, solid or finely fibrous, striate proximally and pointed distally. Apical process rarely distinct and longer than the others. Periphragm fibrous, finely and densely reticulate. Archaeopyle precingular, composed of one or more commonly two discrete plates.

Description: Norvick, 1976, p.53: Exochosphaeridium brevispinum
Chorate cysts with a near-spherical central body and numerous short processes. The latter are solid or fibrous and taper from their slightly expanded bases (1-3 µm in diameter) to pointed extremities. At their bases the fibrils anastomose into a fine and dense periphragmic reticulation. Fibres and lumina are up to 0.5 µm in diameter and the wall is 0.5 to 1 µm thick. At least three processes occur per reflected plate area; they show no trace of alignment. A larger apical process is occasionally developed. The archaeopyle is precingular in position and formed by the loss of one, or more commonly two reflected plate areas.

Dimensions:
The overall diameter ranges from 54 to 81 µm, with an average of 63 µm for 15 specimens.