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Hystrichosphaeridium
From Williams et al., 2017:
[Hystrichosphaeridium, Deflandre, 1937b, p. 68; Emendation: Davey and Williams, 1966b, p. 55-56
Tax. jr. syn.: Dilatisphaera (Appendix A), according to Eisenack et al. (1973, p.407) — however, Cramer and Diez (1979, p.76) retained Dilatisphaera.
Type species: originally as Xanthidium tubiferum, Ehrenberg, 1837b (pl.1, fig.16)] ; Hystrichosphaeridium tubiferum, Deflandre, 1937; emend. Davey and Williams, 1966
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Original description: [Deflandre, 1937]: (Translation: Stover and Evitt 1978, p. 55-57):
Diagnosis:
This genus comprises all Hystrichospheres totally destitute of an equatorial system of elongate plates and whose shell, in general, does not bear fields or plates limited by sutures. The shell, of a dimension greater than 20 µm, is most often spherical or spheroidal; some species, however, are more or less elongate.
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Emended description:
Davey and Williams, 1966:
Description:
Subspherical chorate cysts possessing a reflected tabulation of 4`, (-5`), 6``, 6c, 5-6```, 1p, 1```` and a variable number of sulcal processes.
Processes hollow, open distally, intratabular, one process per plate area. Number of processes rarely exceeding 30.
Archaeopyle apical.
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Modified description:
Stover and Evitt 1978, p. 55-57:
Synopsis:
Cysts skolochorate, gonyaulacacean; body subspherical with 25 to 30 hollow, commonly cylindrical intratabular processes, which are generally open and normally expanded distally and of similar shape; cingular processes present; archeopyle apical, Type tA.
Description:
Shape: Body subspherical.
Wall relationships: Endophragm and periphragm appressed between processes.
Wall features: Normally no parasutural features. Intratabular processes of similar shape, commonly smooth, cylindrical to tubiform, generally open, expanded distally, with denticulate to aculeate tips; periphragm smooth or faintly ornamented.
Paratabulation: Indicated by intratabular processes; gonyaulacacean, process formula: 0-1pr, 4`, 6``, 6c, 5-6```, 1p, 1````, 2-5s.
Archeopyle: Apical, Type tA; principal archeopyle suture zigzag; operculum free.
Paracingulum: Indicated by five or six processes; when only five are present, the process representing the first cingular paraplate is usually missing.
Parasulcus: Indicated by two to five processes, which tend to be more slender than the other processes.
Size: Small to large.
Affinities:
Several genera, all with intratabular processes, are similar to Hystrichosphaeridium and differ from it in the following ways: Oligosphaeridium does not have paracingular processes; Hystrichokolpoma has processes of two different shapes; Surculosphaeridium and Areosphaeridium have solid processes; Cordosphaeridium has fibrous processes and a precingular archeopyle; Perisseiasphaeridium has both solid and hollow processes, the latter usually complexly branched; and Homotryblium has a combination Type A+3A+6P archeopyle.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Hystrichosphaeridium Deflandre, 1937b, emend. Davey and Williams, 1966b. Synopsis from Stover and Evitt (1978, p.55). Cysts skolochorate, gonyaulacacean; body subspherical with 25 to 30 hollow, commonly cylindrical intratabular processes, which are generally open and normally expanded distally and of similar shape; cingular processes present; archeopyle apical, type (tA).
[Hystrichosphaeridium, Deflandre, 1937b, p. 68; Emendation: Davey and Williams, 1966b, p. 55-56
Tax. jr. syn.: Dilatisphaera (Appendix A), according to Eisenack et al. (1973, p.407) — however, Cramer and Diez (1979, p.76) retained Dilatisphaera.
Type species: originally as Xanthidium tubiferum, Ehrenberg, 1837b (pl.1, fig.16)] ; Hystrichosphaeridium tubiferum, Deflandre, 1937; emend. Davey and Williams, 1966
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Original description: [Deflandre, 1937]: (Translation: Stover and Evitt 1978, p. 55-57):
Diagnosis:
This genus comprises all Hystrichospheres totally destitute of an equatorial system of elongate plates and whose shell, in general, does not bear fields or plates limited by sutures. The shell, of a dimension greater than 20 µm, is most often spherical or spheroidal; some species, however, are more or less elongate.
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Emended description:
Davey and Williams, 1966:
Description:
Subspherical chorate cysts possessing a reflected tabulation of 4`, (-5`), 6``, 6c, 5-6```, 1p, 1```` and a variable number of sulcal processes.
Processes hollow, open distally, intratabular, one process per plate area. Number of processes rarely exceeding 30.
Archaeopyle apical.
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Modified description:
Stover and Evitt 1978, p. 55-57:
Synopsis:
Cysts skolochorate, gonyaulacacean; body subspherical with 25 to 30 hollow, commonly cylindrical intratabular processes, which are generally open and normally expanded distally and of similar shape; cingular processes present; archeopyle apical, Type tA.
Description:
Shape: Body subspherical.
Wall relationships: Endophragm and periphragm appressed between processes.
Wall features: Normally no parasutural features. Intratabular processes of similar shape, commonly smooth, cylindrical to tubiform, generally open, expanded distally, with denticulate to aculeate tips; periphragm smooth or faintly ornamented.
Paratabulation: Indicated by intratabular processes; gonyaulacacean, process formula: 0-1pr, 4`, 6``, 6c, 5-6```, 1p, 1````, 2-5s.
Archeopyle: Apical, Type tA; principal archeopyle suture zigzag; operculum free.
Paracingulum: Indicated by five or six processes; when only five are present, the process representing the first cingular paraplate is usually missing.
Parasulcus: Indicated by two to five processes, which tend to be more slender than the other processes.
Size: Small to large.
Affinities:
Several genera, all with intratabular processes, are similar to Hystrichosphaeridium and differ from it in the following ways: Oligosphaeridium does not have paracingular processes; Hystrichokolpoma has processes of two different shapes; Surculosphaeridium and Areosphaeridium have solid processes; Cordosphaeridium has fibrous processes and a precingular archeopyle; Perisseiasphaeridium has both solid and hollow processes, the latter usually complexly branched; and Homotryblium has a combination Type A+3A+6P archeopyle.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Hystrichosphaeridium Deflandre, 1937b, emend. Davey and Williams, 1966b. Synopsis from Stover and Evitt (1978, p.55). Cysts skolochorate, gonyaulacacean; body subspherical with 25 to 30 hollow, commonly cylindrical intratabular processes, which are generally open and normally expanded distally and of similar shape; cingular processes present; archeopyle apical, type (tA).