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Geiselodinium
From Fensome et al., 2019:
Geiselodinium, Krutzsch, 1962, p.42.
Taxonomic junior synonyms: Cubiculosphaera, according to Stover and Evitt (1978, p.230–231); Sanshuia, according to Chen et al. (1988, p.27) -- however, Mao Shaozhi et al. (1995, p.50) retained Sanshuia.
Type: Krutzsch, 1962, pl.11, figs.8–13, as Geiselodinium geiseltalense.
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Original description: [Krutsch, 1962]: (Translation: Stover and Evitt, 1978):
Description:
A genus of the Deflandreidae having a thin central body and a thinner outer wall that are close together. The one apical and two antapical horns are small and the longitudinal and transverse furrows are preserved only as relics and, at times, are nearly vestigial. The furrows are not in contact or, rarely, only just in contact with each other. The outline is roundly oval and the horns do not enter into the outline or only weakly so. Opening absent or indistinct, no tabulation, both bodies weakly punctate.
Affinities:
Geiselodinium differs from Teneridinium in the presence of traces of transverse and longitudinal furrows. It differs from Deflandrea in the strong reduction of the horns and the incompletely developed furrows.
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Modified description:
Stover and Evitt, 1978, p. 230-231:
Synopsis:
Cysts cavate, compressed ellipsoidal, with an apical peak and two small, bluntly rounded antapical lobations; essentially no indications of
paratabulation or of archeopyle.
Description:
Shape: Compressed ellipsoidal with an apical peak and two small, bluntly rounded antapical lobations.
Wall relationships: Cavate; endophragm and periphragm separated by a relatively small pericoel; both wall layers thin and commonly folded.
Wall features: Essentially no parasutural features. Walls thin, commonly folded, weakly punctate.
Paratabulation: Not indicated.
Archeopyle: Apparently not developed.
Paracingulum: Absent or weakly expressed by a faint transverse concavity.
Parasulcus. Absent or vaguely delimited by longitudinal folds.
Size: Intermediate.
Affinities:
Geiselodinium differs from Teneridinium in lacking well-developed apical and antapical horns and in being smaller. The distinction between these genera is indeed slight, and retention of both seems hardly justified.
Geiselodinium, Krutzsch, 1962, p.42.
Taxonomic junior synonyms: Cubiculosphaera, according to Stover and Evitt (1978, p.230–231); Sanshuia, according to Chen et al. (1988, p.27) -- however, Mao Shaozhi et al. (1995, p.50) retained Sanshuia.
Type: Krutzsch, 1962, pl.11, figs.8–13, as Geiselodinium geiseltalense.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Krutsch, 1962]: (Translation: Stover and Evitt, 1978):
Description:
A genus of the Deflandreidae having a thin central body and a thinner outer wall that are close together. The one apical and two antapical horns are small and the longitudinal and transverse furrows are preserved only as relics and, at times, are nearly vestigial. The furrows are not in contact or, rarely, only just in contact with each other. The outline is roundly oval and the horns do not enter into the outline or only weakly so. Opening absent or indistinct, no tabulation, both bodies weakly punctate.
Affinities:
Geiselodinium differs from Teneridinium in the presence of traces of transverse and longitudinal furrows. It differs from Deflandrea in the strong reduction of the horns and the incompletely developed furrows.
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Modified description:
Stover and Evitt, 1978, p. 230-231:
Synopsis:
Cysts cavate, compressed ellipsoidal, with an apical peak and two small, bluntly rounded antapical lobations; essentially no indications of
paratabulation or of archeopyle.
Description:
Shape: Compressed ellipsoidal with an apical peak and two small, bluntly rounded antapical lobations.
Wall relationships: Cavate; endophragm and periphragm separated by a relatively small pericoel; both wall layers thin and commonly folded.
Wall features: Essentially no parasutural features. Walls thin, commonly folded, weakly punctate.
Paratabulation: Not indicated.
Archeopyle: Apparently not developed.
Paracingulum: Absent or weakly expressed by a faint transverse concavity.
Parasulcus. Absent or vaguely delimited by longitudinal folds.
Size: Intermediate.
Affinities:
Geiselodinium differs from Teneridinium in lacking well-developed apical and antapical horns and in being smaller. The distinction between these genera is indeed slight, and retention of both seems hardly justified.