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Baltisphaeridium huguoniotii
Baltisphaeridium huguoniotii, (Valensi, 1955), Downie and Sarjeant, 1965
NOW Sepispinula?. Originally Hystrichosphaeridium, subsequently Baltisphaeridium (Acritarch), thirdly Cleistosphaeridium, fourthly Cleistosphaeridium?, fifthly Chlamydophorella, sixthly Sepispinula, seventhly (and now) Sepispinula?.
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 (now 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.
Holotype: Valensi, 1955, text-fig.2a
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).
NOW Sepispinula?. Originally Hystrichosphaeridium, subsequently Baltisphaeridium (Acritarch), thirdly Cleistosphaeridium, fourthly Cleistosphaeridium?, fifthly Chlamydophorella, sixthly Sepispinula, seventhly (and now) Sepispinula?.
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 (now 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.
Holotype: Valensi, 1955, text-fig.2a
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).