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Renidinium
From Williams et al., 2017:
[Renidinium, Morgenroth, 1968, p. 551-552
Type species: Renidinium membraniferum, Morgenroth, 1968 (pl.47, fig.1)]
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Original description: [Morgenroth, 1968]: (Translation: Stover and Evitt, 1978, p. 78):
Description:
A dinoflagellate genus with the following characteristics: The theca on the ventral side is depressed slightly and has a more or less clear projection at the apex. The antapex is marked by 2 dissimilar, commonly strongly developed protrusions. The dorsal side of the theca shows a tabulation which is produced by the connections between the theca and the outer membrane – which may or may not be drawn into processes. On the ventral surface the outer membrane forms 2 meridionally aligned bulges on the 2 sides of the longitudinal furrow. The outer membrane protrudes as one lobe at the apex and commonly as 2 lobes at the antapex. They can, however, envelop the antapex as undifferentiated sack-like structures. The untabulated ventral side of the theca is characterized by having a longitudinal furrow extending from the apex to the antapex where it is bordered by the beginnings of the 2 bulges of the outer membrane.
On the dorsal side is a somewhat equatorial transverse furrow above which are 3 low trapezoidal plates. Opposed to these and below the transverse furrow are also 3 trapezoidal plates.
No differentiated plates are recognized at the apex and antapex.
The archeopyle, whose outline is irregularly jagged, forms following the disassociation of the apical cap.
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Modified description:
Stover and Evitt, 1978, p. 78-79:
Synopsis:
Cysts proximate, endocyst lenticular; endophragm and periphragm separated on right and left side of ventral surface, appressed or close together elsewhere; gonyaulacacean; paratabulation expressed incompletely by penitabular ridges or folds on the periphragm; archeopyle apical, Type (tA); parasulcal notch offset.
Description:
Shape: Endocyst lenticular; outline of periphragm basically subcircular in dorsal-ventral view, and modified by an apical and two antapical protrusions. Outline of periphragm in apical-antapical view reniform with midventral concavity.
Wall relationships: Endophragm and periphragm separated widely on right and left sides of the ventral surface, resulting in the formation of two ventral pericoels; wall layers appressed or close together elsewhere.
Wall features: No parasutural features. Penitabular ridges or folds on the periphragm continuous or discontinuous, smooth or areolate, and generally more clearly developed on the dorsal than on the ventral surface. Periphragm smooth to areolate; endophragm finely granulate to punctoreticulate.
Paratabulation: Indicated incompletely by archeopyle and penitabular ridges; gonyaulacacean, formula: 4`, 5-6``, Xc, 3-5```, 0-1p, 1````.
Archeopyle: ApicaI, Type (tA); principalarcheopyle suture zigzag with offset parasulcal notch; operculum free.
Paracingulum: Indicated incompletely as a narrow transverse area between opposing precingular and postcingular penitabular ridges.
Parasulcus: Position of apical end inferred from the location of the parasulcal notch; other indications lacking.
Size: Small to intermediate.
Affinities:
Renidinium differs from Palynodinium in having the paratabulation expressed by penitabular ridges instead of gonal and intergonal processes. It differs from Senoniasphaera in that the pericoels are developed ventrally rather than along both surfaces.
[Renidinium, Morgenroth, 1968, p. 551-552
Type species: Renidinium membraniferum, Morgenroth, 1968 (pl.47, fig.1)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Morgenroth, 1968]: (Translation: Stover and Evitt, 1978, p. 78):
Description:
A dinoflagellate genus with the following characteristics: The theca on the ventral side is depressed slightly and has a more or less clear projection at the apex. The antapex is marked by 2 dissimilar, commonly strongly developed protrusions. The dorsal side of the theca shows a tabulation which is produced by the connections between the theca and the outer membrane – which may or may not be drawn into processes. On the ventral surface the outer membrane forms 2 meridionally aligned bulges on the 2 sides of the longitudinal furrow. The outer membrane protrudes as one lobe at the apex and commonly as 2 lobes at the antapex. They can, however, envelop the antapex as undifferentiated sack-like structures. The untabulated ventral side of the theca is characterized by having a longitudinal furrow extending from the apex to the antapex where it is bordered by the beginnings of the 2 bulges of the outer membrane.
On the dorsal side is a somewhat equatorial transverse furrow above which are 3 low trapezoidal plates. Opposed to these and below the transverse furrow are also 3 trapezoidal plates.
No differentiated plates are recognized at the apex and antapex.
The archeopyle, whose outline is irregularly jagged, forms following the disassociation of the apical cap.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt, 1978, p. 78-79:
Synopsis:
Cysts proximate, endocyst lenticular; endophragm and periphragm separated on right and left side of ventral surface, appressed or close together elsewhere; gonyaulacacean; paratabulation expressed incompletely by penitabular ridges or folds on the periphragm; archeopyle apical, Type (tA); parasulcal notch offset.
Description:
Shape: Endocyst lenticular; outline of periphragm basically subcircular in dorsal-ventral view, and modified by an apical and two antapical protrusions. Outline of periphragm in apical-antapical view reniform with midventral concavity.
Wall relationships: Endophragm and periphragm separated widely on right and left sides of the ventral surface, resulting in the formation of two ventral pericoels; wall layers appressed or close together elsewhere.
Wall features: No parasutural features. Penitabular ridges or folds on the periphragm continuous or discontinuous, smooth or areolate, and generally more clearly developed on the dorsal than on the ventral surface. Periphragm smooth to areolate; endophragm finely granulate to punctoreticulate.
Paratabulation: Indicated incompletely by archeopyle and penitabular ridges; gonyaulacacean, formula: 4`, 5-6``, Xc, 3-5```, 0-1p, 1````.
Archeopyle: ApicaI, Type (tA); principalarcheopyle suture zigzag with offset parasulcal notch; operculum free.
Paracingulum: Indicated incompletely as a narrow transverse area between opposing precingular and postcingular penitabular ridges.
Parasulcus: Position of apical end inferred from the location of the parasulcal notch; other indications lacking.
Size: Small to intermediate.
Affinities:
Renidinium differs from Palynodinium in having the paratabulation expressed by penitabular ridges instead of gonal and intergonal processes. It differs from Senoniasphaera in that the pericoels are developed ventrally rather than along both surfaces.