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Eocladopyxis
From Williams et al., 2017:
[Eocladopyxis, Morgenroth, 1966a, p.7; Emendation: Stover and Evitt, 1978, p. 206–207.
Type species: Eocladopyxis peniculata, Morgenroth, 1966a (pl.3, figs.2–30)]
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Original description: [Morgenroth, 1966]: (Translation: Stover and Evitt, 1978, p. 206)
Description:
The spherical shell shows a distinct tabulation. The sutures are slightly depressed. Each plate -not its border!- is occupied by a few processes.
Epitheca and hypotheca are approximately equal in size. The plated girdle is laevorotatory and is not depressed. A distinct wide longitudinal furrow is present. Tabulation formula: 3`, 6``, ?6g, ?5```, 1p, 1ppl, 1````.
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Emended description:
Stover and Evitt, 1978:
Synopsis:
Cysts skolochorate, acavate; body subspherical with numerous nontabular processes; paratabulation gonyaulacacean, indicated on hypocyst by narrow parasutural grooves and on epicyst by opercular pieces of combination archeopyle, Type A+3A+6P.
Description:
Shape: Body subspherical.
Wall relationships: Endophragm and periphragm appressed between processes; acavate.
Wall features: Narrow parasutural grooves present on hypocyst; on epicyst, opercular pieces separate along paraplate boundaries. Processes nontabular, closed or open distally, few to several processes per paraplate; surface between processes finely granulate to punctoreticulate.
Paratabulation: Indicated by parasutural features on hypocyst and by archeopyle sutures and opercular pieces on epicyst; gonyaulacacean, formula: 1pr, 4`, 6``, 6c, 5```,1p, 1````, 2s; postcingular paraplates interpreted as representing plates 2`` to 6``.
Archeopyle: Combination archeopyle, Type A+3A+6P; principal archeopyle suture straight along apical margin of paracingulum except at midventral surface, where it follows the outline of the parasulcal tab and the shallow depression on its right side. Parasulcal tab corresponds to high position of anterior sulcal paraplate; the depression corresponds to low position of paraplate 6". Six precingular and first apical paraplates separate individually; apical paraplates 2` to 4` remain together, although separated from other seven opercular pieces; operculum free.
Paracingulum: Indicated by six elongate paraplates along archeopyle margin and outlined by narrow parasutural grooves.
Parasulcus: Outlined by parasutural features and may be subdivided; apical limit indicated by parasulcal tab.
Size: Small to intermediate.
Affinities:
Eocladopyxis differs from Hemicystodinium in that its paratabulation is indicated by parasutural grooves on the hypocyst; such features are lacking on Hemicystodinium. Additionally, there is a tendency for the hypocysts of Eocladopyxis to disarticulate, generally along paraplate boundaries, although some paracingular and adjoining postcingular paraplates commonly remain together.
[Eocladopyxis, Morgenroth, 1966a, p.7; Emendation: Stover and Evitt, 1978, p. 206–207.
Type species: Eocladopyxis peniculata, Morgenroth, 1966a (pl.3, figs.2–30)]
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Original description: [Morgenroth, 1966]: (Translation: Stover and Evitt, 1978, p. 206)
Description:
The spherical shell shows a distinct tabulation. The sutures are slightly depressed. Each plate -not its border!- is occupied by a few processes.
Epitheca and hypotheca are approximately equal in size. The plated girdle is laevorotatory and is not depressed. A distinct wide longitudinal furrow is present. Tabulation formula: 3`, 6``, ?6g, ?5```, 1p, 1ppl, 1````.
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Emended description:
Stover and Evitt, 1978:
Synopsis:
Cysts skolochorate, acavate; body subspherical with numerous nontabular processes; paratabulation gonyaulacacean, indicated on hypocyst by narrow parasutural grooves and on epicyst by opercular pieces of combination archeopyle, Type A+3A+6P.
Description:
Shape: Body subspherical.
Wall relationships: Endophragm and periphragm appressed between processes; acavate.
Wall features: Narrow parasutural grooves present on hypocyst; on epicyst, opercular pieces separate along paraplate boundaries. Processes nontabular, closed or open distally, few to several processes per paraplate; surface between processes finely granulate to punctoreticulate.
Paratabulation: Indicated by parasutural features on hypocyst and by archeopyle sutures and opercular pieces on epicyst; gonyaulacacean, formula: 1pr, 4`, 6``, 6c, 5```,1p, 1````, 2s; postcingular paraplates interpreted as representing plates 2`` to 6``.
Archeopyle: Combination archeopyle, Type A+3A+6P; principal archeopyle suture straight along apical margin of paracingulum except at midventral surface, where it follows the outline of the parasulcal tab and the shallow depression on its right side. Parasulcal tab corresponds to high position of anterior sulcal paraplate; the depression corresponds to low position of paraplate 6". Six precingular and first apical paraplates separate individually; apical paraplates 2` to 4` remain together, although separated from other seven opercular pieces; operculum free.
Paracingulum: Indicated by six elongate paraplates along archeopyle margin and outlined by narrow parasutural grooves.
Parasulcus: Outlined by parasutural features and may be subdivided; apical limit indicated by parasulcal tab.
Size: Small to intermediate.
Affinities:
Eocladopyxis differs from Hemicystodinium in that its paratabulation is indicated by parasutural grooves on the hypocyst; such features are lacking on Hemicystodinium. Additionally, there is a tendency for the hypocysts of Eocladopyxis to disarticulate, generally along paraplate boundaries, although some paracingular and adjoining postcingular paraplates commonly remain together.