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Cleistosphaeridium polypetellum
Cleistosphaeridium polypetellum, (Islam, 1983c, p.82,84, pl.2, figs.1-6), Stover and Williams, 1995, p.102.
Originally Areosphaeridium, subsequently (and now) Cleistosphaeridium. Taxonomic senior synonym: Cleistosphaeridium (as Systematophora) diversispinosum, according to Islam (1993, p.88) - however, Eaton et al. (2001, p. 194) retained Cleistosphaeridium polypetellum. Eaton et al. (2001, p.194) also proposed this combination.
Holotype: Islam, 1983c, pl.2, fig.1.
Age: Early-Mid Eocene.
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Original description: [Islam, 1983, p. 84]:
Diagnosis:
Autocyst subspherical to lenticular with chagrinate, granulate or reticulate surface; possesses numerous intratabular solid and partly somewhat fibrous processes with 1-2 µm thick stems, generally 3-4 per paraplate and can be as many as 6 in the antapical paraplate, proximally wide and sometimes joining with others in the same paraplate to produce partial or arcuate process complexes, some processes branched, proximal coalescence of processes sometimes results in low level branching, distally ramified into palm-like expansions with indented margins unlike distal platforms seen in some species of Areosphaeridium and appear as if distally divergent bifurcations joined with membrane in a palm-like fashion, sometimes posterior processes bear distally interconnecting trabeculae, rarely distal expansions of processes fenestrate but frequently not well developed; paracingulum narrow and looks bare of processes;
paratabulation 4", 6", ?c, 6""", 1p, 1"""";
parasulcus not recognizable;
archeopyle apical type 4A with free operculum.
Dimensions:
Holotype: cyst body 47 x 49 µm, length of processes 12-20 µm.
Range: cyst length 36(47)57 µm, breadth 37(46)55 µm, length of processes 7-20 µm.
Affinities:
This species differs from other species of the genus in number and morphology of the processes. It resembles Cleistosphaeridium Davey et al. 1966 most closely but differs in the intratabular distribution of its processes which is recognizable in relatively few specimens. It also resembles Adnatosphaeridium Williams & Downie 1966 in possessing trabecular distal process connections, and Areoligera Lejeune-Carpentier 1938 and Systematophora Klement 1960 in possessing process complexes, but these are only exceptional features of the species. However, whether these features have any phyletic significance is not known.
Originally Areosphaeridium, subsequently (and now) Cleistosphaeridium. Taxonomic senior synonym: Cleistosphaeridium (as Systematophora) diversispinosum, according to Islam (1993, p.88) - however, Eaton et al. (2001, p. 194) retained Cleistosphaeridium polypetellum. Eaton et al. (2001, p.194) also proposed this combination.
Holotype: Islam, 1983c, pl.2, fig.1.
Age: Early-Mid Eocene.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Islam, 1983, p. 84]:
Diagnosis:
Autocyst subspherical to lenticular with chagrinate, granulate or reticulate surface; possesses numerous intratabular solid and partly somewhat fibrous processes with 1-2 µm thick stems, generally 3-4 per paraplate and can be as many as 6 in the antapical paraplate, proximally wide and sometimes joining with others in the same paraplate to produce partial or arcuate process complexes, some processes branched, proximal coalescence of processes sometimes results in low level branching, distally ramified into palm-like expansions with indented margins unlike distal platforms seen in some species of Areosphaeridium and appear as if distally divergent bifurcations joined with membrane in a palm-like fashion, sometimes posterior processes bear distally interconnecting trabeculae, rarely distal expansions of processes fenestrate but frequently not well developed; paracingulum narrow and looks bare of processes;
paratabulation 4", 6", ?c, 6""", 1p, 1"""";
parasulcus not recognizable;
archeopyle apical type 4A with free operculum.
Dimensions:
Holotype: cyst body 47 x 49 µm, length of processes 12-20 µm.
Range: cyst length 36(47)57 µm, breadth 37(46)55 µm, length of processes 7-20 µm.
Affinities:
This species differs from other species of the genus in number and morphology of the processes. It resembles Cleistosphaeridium Davey et al. 1966 most closely but differs in the intratabular distribution of its processes which is recognizable in relatively few specimens. It also resembles Adnatosphaeridium Williams & Downie 1966 in possessing trabecular distal process connections, and Areoligera Lejeune-Carpentier 1938 and Systematophora Klement 1960 in possessing process complexes, but these are only exceptional features of the species. However, whether these features have any phyletic significance is not known.