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Tapeinosphaeridium
From Williams et al., 2017:
[Tapeinosphaeridium Ioannides, Stavrinos and Downie, 1977, p. 461–462
Type species: Tapeinosphaeridium pericompsum, Ioannides et al. 1977 (pl.5, fig.1)]
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Original description: [Ioannides, Stavrinos and Downie, 1977]:
Description:
Shell spherical to elongate; shell wall thin, single-layered; surface smooth to granular. Infrequently, tabulation may be faintly indicated but not determined. Cingulum poorly marked or absent; sulcus not observed. Dorsal surface usually showing archeopyle developed by loss of one plate, corresponding to precingular position.
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Modified description:
Stover and Evitt, 1978, p. 193:
Synopsis:
Cysts proximate, subspherical; autophragm thin, commonly folded, smooth or with features of low relief; paratabulation normally indicated by precingular, Type P, archeopyle.
Description:
Shape: Subspherical.
Wall relationships: Autophragm only.
Wall features: No parasutural features; thin autophragm smooth or with features of low relief, commonly folded.
Paratabulation: Normally expressed by archeopyle only; other indications vague.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Generally not indicated.
Parasulcus: Not indicated.
Size: Small to intermediate.
Affinities:
Tapeinosphaeridium differs from Tectatodinium in having a thin commonly folded autophragm instead of a thick two-layered wall. It differs from Chytroeisphaeridia in having a precingular archeopyle rather than an apical archeopyle.
[Tapeinosphaeridium Ioannides, Stavrinos and Downie, 1977, p. 461–462
Type species: Tapeinosphaeridium pericompsum, Ioannides et al. 1977 (pl.5, fig.1)]
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Original description: [Ioannides, Stavrinos and Downie, 1977]:
Description:
Shell spherical to elongate; shell wall thin, single-layered; surface smooth to granular. Infrequently, tabulation may be faintly indicated but not determined. Cingulum poorly marked or absent; sulcus not observed. Dorsal surface usually showing archeopyle developed by loss of one plate, corresponding to precingular position.
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Modified description:
Stover and Evitt, 1978, p. 193:
Synopsis:
Cysts proximate, subspherical; autophragm thin, commonly folded, smooth or with features of low relief; paratabulation normally indicated by precingular, Type P, archeopyle.
Description:
Shape: Subspherical.
Wall relationships: Autophragm only.
Wall features: No parasutural features; thin autophragm smooth or with features of low relief, commonly folded.
Paratabulation: Normally expressed by archeopyle only; other indications vague.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Generally not indicated.
Parasulcus: Not indicated.
Size: Small to intermediate.
Affinities:
Tapeinosphaeridium differs from Tectatodinium in having a thin commonly folded autophragm instead of a thick two-layered wall. It differs from Chytroeisphaeridia in having a precingular archeopyle rather than an apical archeopyle.