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Cleistosphaeridium diversispinosum

Cleistosphaeridium diversispinosum, Davey et al., 1966, p.167, pl.10, fig.7; Emendation: Eaton et al., 2001, p.177.

Originally (and now) Cleistosphaeridium, subsequently Systematophora. Eaton et al. (2001, p.177) retained this species in Cleistosphaeridium.
Taxonomic junior synonym: Areosphaeridium polypetellum, according to Islam (1993, p.88) - however, Eaton et al. (2001, p. 194) retained Cleistosphaeridium polypetellum.

Holotype: Davey et al., 1966, pl.10, fig.7; Bujak et al., 1980, pl.7, figs.7-8; Islam, 1993, pl.1, figs.1-10; text-figs.1A-B; Eaton et al., 2001, figs1A-B,2A-B; Fauconnier and Masure, 2004, pl.77, fig.9.
Locus typicus: Whitecliff, England
Stratum typicum: London Clay, Early Eocene

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Original description: [Davey et al., 1966, p.167]:

Diagnosis:
A Cleistosphaeridium with granular wall and polygonal archaeopyle. Processes solid, taeniate or tubular, usually slender and proximally expanded. Distal end forked or expanded.

Description:
This species is distinguished by the variable nature of the process ends. The expanded termination may be bifurcate, orthogonal and patulate, one branch may be larger than the other. The edges are usually denticulate and the processes may be up to 5 µm wide; but are usually about 2 µm. There is more than one process to a plate.

Dimensions:
Holotype: diameter of the body 38 µm, length of processes 9-16 µm.
Observed range: diameter of body 38 µm, length of processes 7-23 µm.

Affinities:
Only Cleistosphaeridium pectiniforme (Gerlach, 1961) resembles C. diversispinosum to any degree. It has widely forked processes with spinose margins; it does not, however, have a variability of process ending shown by our species.
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