Cleistosphaeridium selseyense, Islam, 1983

Holotype: Islam, 1983, pl.2, fig.3
Locus typicus: Hampshire Basin, S England
Stratum typicum: Middle Eocene

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Original description: [Islam, 1983, p. 337]:

Diagnosis:
Autocyst subspherical; surface mildly reticulate; skolochorate to proximochorate; numerous nontabular solid processes a third to a quarter of average cyst diameter in length, proximally wide and taeniate and sometimes joined proximally to adjacent ones, tapering rapidly to thin, slender forms at or below mid-length and continue as such to distal bifurcations; archeopyle apical type tA, operculum free or attached. In some forms, a thin psilate proximal membrane connects most processes, a feature found in some species of Impletosphaeridium (Islam 1983).

Dimensions:
Holotype: cyst diameter 30 µm, length of processes 4-7 µm.
Range: cyst diameter 31 (26)22 µm, length of processes 3-8 µm. Specimens measured: 10.

Affinities:
This species differs from others of the genus in possessing proximally taeniate and distally thin solid processes, and smaller size.