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Cleistosphaeridium huguoniotii
From Fensome et al., 2019:
Cleistosphaeridium huguoniotii (Valensi, 1955a, p.38–39, text-fig.2a) Davey, 1969a, p.155–156. Holotype: Valensi, 1955a, text-fig.2a; Fauconnier and Masure, 2004, pl.72, figs.1–3. NOW Sepispinula?. Originally Hystrichosphaeridium, subsequently Baltisphaeridium (Appendix A), thirdly Cleistosphaeridium, fourthly Cleistosphaeridium?, fifthly Chlamydophorella, sixthly Sepispinula, seventhly (and now) Sepispinula?. Questionable assignment: Stover and Evitt (1978, p.32) as a problematic species. Taxonomic senior synonym: Micrhystridium (as Polysphaeridium, now Sepispinula?) ambiguum, according to Yun Hyesu (1981, p.44) and Schiøler and Wilson (1998, p.328) — however, Masure in Fauconnier and Masure (2004, p.500) retained Hystrichosphaeridium (as and now Sepispinula?) huguoniotii. Taxonomic junior synonym: Hystrichosphaeridium (subsequently Sepispinula) ancoriferum, according to Clarke and Verdier (1967, p.54) — however, Masure in Fauconnier and Masure (2004, p.499) retained Hystrichosphaeridium (as and now Sepispinula) ancoriferum. Age: Late Cretaceous.
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Original description: [Valensi, 1955, p. 38-39] (translated from French):
Holotype: Cretaceous flint from Venesmes.
The shell of circular or ellipsoidal outline is covered with numerous radiating processes, short and of equal length. These rod-shaped processes end in spines, generally two in number, and approximately perpendicular to their axis; they are hollow and their cavity does not seem to communicate with that of the shell; their base is sometimes widened and conical. I counted half a dozen in the same plane over a length of 10 μ from the edge of the shell.
The color is light brown, the surface smooth or very slightly granular. The cavity of the shell often contains grains of red material. Fossilization can lead to the formation of folds that unite the bases of the processes, thus simulating the outline of a network.
I encountered about fifteen individuals of this species, which is therefore relatively common. Its dimensions vary from 29 to 33 μ for the major axis of the shell alone and from 25 to 29 μ for the minor axis; the total span with the processes, which are from 4 to 7 μ long, varies from 33 to 41 μ.
The processes have the same shape as in Micrhystridium ambiguum Defl. of Cretaceous and Jurassic flints, but Hystrichosphaeridium huguonioti is distinguished from this species by its dimensions and its more numerous processes, the extremities of which never give the impression of surrounding the shell with an imaginary circle parallel to its surface. It is also close to Hystrichosphaeridium malleoforum (White) Defl. from the Cretaceous, from which it differs however by its much denser processes ending in spines and not in lobes, as well as by its much smaller size (33 to 41 μ instead of 63 to 85 μ).
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Supplemental description:
Davey, 1969, p.135:
Description:
The shell is subspherical; the shell wall is smooth and gives rise to numerous bifurcating processes which are not aligned to any noticeable extent.
Most of the specimens possess an apical archaeopyle! the shape of which is usually difficult to determine because of distortion. However, detached apical regions are common and are 6-sided. The processes are hollow, the central cavity often being constricted to some extent along its length, and closed distally and proximally. The sides of the processes are practically parallel, diverging slightly proximally before joining the shell. Distally they give rise to two slightly recurved spines. Cookson and Eisenack comment on the " transparent tips " of the processes. The extremities of the processes are in fact closed by a thin, transparent membrane. The processes may be isolate or a few may be linked together distally by their spines. The shell wall rarely forms a small rounded apical bulge.
Dimensions:
Range of observed specimens: diameter of central body 20(31.8)45 µm, length of processes up to 8 µm. Number of specimens measured, 30.
Cleistosphaeridium huguoniotii (Valensi, 1955a, p.38–39, text-fig.2a) Davey, 1969a, p.155–156. Holotype: Valensi, 1955a, text-fig.2a; Fauconnier and Masure, 2004, pl.72, figs.1–3. NOW Sepispinula?. Originally Hystrichosphaeridium, subsequently Baltisphaeridium (Appendix A), thirdly Cleistosphaeridium, fourthly Cleistosphaeridium?, fifthly Chlamydophorella, sixthly Sepispinula, seventhly (and now) Sepispinula?. Questionable assignment: Stover and Evitt (1978, p.32) as a problematic species. Taxonomic senior synonym: Micrhystridium (as Polysphaeridium, now Sepispinula?) ambiguum, according to Yun Hyesu (1981, p.44) and Schiøler and Wilson (1998, p.328) — however, Masure in Fauconnier and Masure (2004, p.500) retained Hystrichosphaeridium (as and now Sepispinula?) huguoniotii. Taxonomic junior synonym: Hystrichosphaeridium (subsequently Sepispinula) ancoriferum, according to Clarke and Verdier (1967, p.54) — however, Masure in Fauconnier and Masure (2004, p.499) retained Hystrichosphaeridium (as and now Sepispinula) ancoriferum. Age: Late Cretaceous.
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Original description: [Valensi, 1955, p. 38-39] (translated from French):
Holotype: Cretaceous flint from Venesmes.
The shell of circular or ellipsoidal outline is covered with numerous radiating processes, short and of equal length. These rod-shaped processes end in spines, generally two in number, and approximately perpendicular to their axis; they are hollow and their cavity does not seem to communicate with that of the shell; their base is sometimes widened and conical. I counted half a dozen in the same plane over a length of 10 μ from the edge of the shell.
The color is light brown, the surface smooth or very slightly granular. The cavity of the shell often contains grains of red material. Fossilization can lead to the formation of folds that unite the bases of the processes, thus simulating the outline of a network.
I encountered about fifteen individuals of this species, which is therefore relatively common. Its dimensions vary from 29 to 33 μ for the major axis of the shell alone and from 25 to 29 μ for the minor axis; the total span with the processes, which are from 4 to 7 μ long, varies from 33 to 41 μ.
The processes have the same shape as in Micrhystridium ambiguum Defl. of Cretaceous and Jurassic flints, but Hystrichosphaeridium huguonioti is distinguished from this species by its dimensions and its more numerous processes, the extremities of which never give the impression of surrounding the shell with an imaginary circle parallel to its surface. It is also close to Hystrichosphaeridium malleoforum (White) Defl. from the Cretaceous, from which it differs however by its much denser processes ending in spines and not in lobes, as well as by its much smaller size (33 to 41 μ instead of 63 to 85 μ).
--------------------------------------------------------------------------------------------------
Supplemental description:
Davey, 1969, p.135:
Description:
The shell is subspherical; the shell wall is smooth and gives rise to numerous bifurcating processes which are not aligned to any noticeable extent.
Most of the specimens possess an apical archaeopyle! the shape of which is usually difficult to determine because of distortion. However, detached apical regions are common and are 6-sided. The processes are hollow, the central cavity often being constricted to some extent along its length, and closed distally and proximally. The sides of the processes are practically parallel, diverging slightly proximally before joining the shell. Distally they give rise to two slightly recurved spines. Cookson and Eisenack comment on the " transparent tips " of the processes. The extremities of the processes are in fact closed by a thin, transparent membrane. The processes may be isolate or a few may be linked together distally by their spines. The shell wall rarely forms a small rounded apical bulge.
Dimensions:
Range of observed specimens: diameter of central body 20(31.8)45 µm, length of processes up to 8 µm. Number of specimens measured, 30.