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Hystrichosphaeridium fucosum
Hystrichosphaeridium fucosum (Valensi, 1955) Downie and Sarjeant, 1965
NOW Litosphaeridium. Originally Micrhystridium, subsequently Hystrichosphaeridium, thirdly Polysphaeridium?, fourthly Dapsilidinium?, fifthly (and now) Litosphaeridium.
Taxonomic junior synonyms: Hystrichosphaeridium tubiferum var. brevispinum, according to Below (1982c, p.29) — however, Lentin and Williams (1985, p.190) retained Hystrichosphaeridium tubiferum subsp. brevispinum; Hystrichosphaeridium (as Litosphaeridium) arundum, according to Below (1982c, p.29) — however, Lentin and Williams (1985, p.227) retained Litosphaeridium arundum.
Holotype: Valensi, 1955a, text-fig.2b; Fauconnier and Masure, 2004, pl.52, figs.8–11.
Age: Late Cretaceous
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Original description: [Valensi, 1955] (translated from French):
Holotype (unique): Cretaceous flint from Venesmes.
The ovoid shell has about twenty tube-like processes whose length is between a third and a half of its diameter. These tubes are hollow, of circular section, and their cavity does not seem to communicate with that of the shell; slightly widened at their base, they flare out a little at their end. The surface of the shell is granular and the color light brown.
The size is 20 to 24 μ for the shell alone, 7 to 10 μ for the processes and 30 to 35 μ for the total span.
Despite the absence of spines on the edges of the terminal funnel of the processes, Micrhystridium fucosum is undoubtedly a "Tubifer", but its small size and short processes distance it from Hystrichosphaeridium tubiferum and its more than double size, from Micrhystridium paulinae Val. of the Jurassic.
NOW Litosphaeridium. Originally Micrhystridium, subsequently Hystrichosphaeridium, thirdly Polysphaeridium?, fourthly Dapsilidinium?, fifthly (and now) Litosphaeridium.
Taxonomic junior synonyms: Hystrichosphaeridium tubiferum var. brevispinum, according to Below (1982c, p.29) — however, Lentin and Williams (1985, p.190) retained Hystrichosphaeridium tubiferum subsp. brevispinum; Hystrichosphaeridium (as Litosphaeridium) arundum, according to Below (1982c, p.29) — however, Lentin and Williams (1985, p.227) retained Litosphaeridium arundum.
Holotype: Valensi, 1955a, text-fig.2b; Fauconnier and Masure, 2004, pl.52, figs.8–11.
Age: Late Cretaceous
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Original description: [Valensi, 1955] (translated from French):
Holotype (unique): Cretaceous flint from Venesmes.
The ovoid shell has about twenty tube-like processes whose length is between a third and a half of its diameter. These tubes are hollow, of circular section, and their cavity does not seem to communicate with that of the shell; slightly widened at their base, they flare out a little at their end. The surface of the shell is granular and the color light brown.
The size is 20 to 24 μ for the shell alone, 7 to 10 μ for the processes and 30 to 35 μ for the total span.
Despite the absence of spines on the edges of the terminal funnel of the processes, Micrhystridium fucosum is undoubtedly a "Tubifer", but its small size and short processes distance it from Hystrichosphaeridium tubiferum and its more than double size, from Micrhystridium paulinae Val. of the Jurassic.