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Rigaudella
From Williams et al., 2017:
[Rigaudella, Below, 1982b, p. 138-139
Type species: originally as Hystrichosphaeridium aemulum, Deflandre, 1939a (pl.11, fig.1)] ; Rigaudella aemula, (Deflandre, 1938), emend. Below, 1982
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Original description: [Below, 1982]: (Translations: Stover and Williams, 1987, p. 192 (original description) and LPP):
Diagnosis:
Cysts are spheroidal, skolochorate, and ?two-layered. Solid and/or hollow, generally distally expanded, intratabular processes are connected to one another distally by solid trabeculae. Process formula follows the gonyaulacoidal pattern: 1-4`, 1-6``, 0c, 0s, 2-5``` (2-6```), pc, 1````, with only one process per paraplate. Archaeopyle apical with compound operculum, type 4A(1-4`).
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Modified description:
Stover and Williams, 1987, p. 191-192:
Synopis:
Cysts skolochorate, body subspherical with approximately 17, solid and/or hollow, generally funnel-shaped, less commonly slender, distally-branched intratabular processes; expanded parts of processes irregularly fenestrate and connected to adjacent processes by trabeculae; cingular processes absent, archaeopyle apical, type (4A), operculum free.
Description:
Shape: Body subspherical.
Wall relationships: Undifferentiated autophragm.
Wall features: Intratabular processes solid and/or hollow, mostly funnel-shaped, with irregularly fenestrate distal parts; some processes may be slender with distal branches, on others the narrow proximal part may be very short or lacking; distal ends of processes connected to adjacent processes by trabeculae. Body and processes smooth or faintly ornamented.
Archaeopyle: apical, type (4A); operculum free.
Paratabulation: Indicated by intratabular processes; gonyaulacacean, formula: 4`, 6``, 0c, 4-5```, 1p, 1````, 0s.
Paracingulum: Indicated by the absence of cingular processes.
Parasulcus: Not indicated.
Size: Intermediate to large, overall size about 80 to 130 μm.
Remark:
Below, 1982, interpreted the archaeopyle as apical type 4A, implying that the four apical paraplates separate consistently as four operculer pieces. In our experience, such is not the case. The apical paraplates almost always remain together as a single opercular piece (archaeopyle type [4A]).
Affinities:
Rigaudella differs from Adnatosphaeridium Williams and Downie in Davey et al., 1966, in having funnel-shaped intratabular processes, and in lacking cingular processes. Adnatosphaeridium has more numerous processes or process-complexes, of which some are certainly cingular, and a more complexly-developed trabecular network.
On Emmetrocysta Stover, 1975, the processes are of more uniform width (diameter) than those on Rigaudella, have distal ring trabeculae, and few or none are interconnected by trabeculae.
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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.
Rigaudella Below, 1982b. Diagnosis from Below (1982b, p.138) Cysts are spheroidal, skolochorate, and ?two-layered. Solid and/or hollow, generally distally expanded, intratabular processes are connected to one another distally by solid trabeculae. Process formula follows the gonyaulacoid pattern 1-4`, 1-6", 0c, 0s, 2-5"' (2-6"'), pc, 1"'' , with only one process per paraplate. Archeopyle apical with compound operculum, type 4A.
[Rigaudella, Below, 1982b, p. 138-139
Type species: originally as Hystrichosphaeridium aemulum, Deflandre, 1939a (pl.11, fig.1)] ; Rigaudella aemula, (Deflandre, 1938), emend. Below, 1982
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Below, 1982]: (Translations: Stover and Williams, 1987, p. 192 (original description) and LPP):
Diagnosis:
Cysts are spheroidal, skolochorate, and ?two-layered. Solid and/or hollow, generally distally expanded, intratabular processes are connected to one another distally by solid trabeculae. Process formula follows the gonyaulacoidal pattern: 1-4`, 1-6``, 0c, 0s, 2-5``` (2-6```), pc, 1````, with only one process per paraplate. Archaeopyle apical with compound operculum, type 4A(1-4`).
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Modified description:
Stover and Williams, 1987, p. 191-192:
Synopis:
Cysts skolochorate, body subspherical with approximately 17, solid and/or hollow, generally funnel-shaped, less commonly slender, distally-branched intratabular processes; expanded parts of processes irregularly fenestrate and connected to adjacent processes by trabeculae; cingular processes absent, archaeopyle apical, type (4A), operculum free.
Description:
Shape: Body subspherical.
Wall relationships: Undifferentiated autophragm.
Wall features: Intratabular processes solid and/or hollow, mostly funnel-shaped, with irregularly fenestrate distal parts; some processes may be slender with distal branches, on others the narrow proximal part may be very short or lacking; distal ends of processes connected to adjacent processes by trabeculae. Body and processes smooth or faintly ornamented.
Archaeopyle: apical, type (4A); operculum free.
Paratabulation: Indicated by intratabular processes; gonyaulacacean, formula: 4`, 6``, 0c, 4-5```, 1p, 1````, 0s.
Paracingulum: Indicated by the absence of cingular processes.
Parasulcus: Not indicated.
Size: Intermediate to large, overall size about 80 to 130 μm.
Remark:
Below, 1982, interpreted the archaeopyle as apical type 4A, implying that the four apical paraplates separate consistently as four operculer pieces. In our experience, such is not the case. The apical paraplates almost always remain together as a single opercular piece (archaeopyle type [4A]).
Affinities:
Rigaudella differs from Adnatosphaeridium Williams and Downie in Davey et al., 1966, in having funnel-shaped intratabular processes, and in lacking cingular processes. Adnatosphaeridium has more numerous processes or process-complexes, of which some are certainly cingular, and a more complexly-developed trabecular network.
On Emmetrocysta Stover, 1975, the processes are of more uniform width (diameter) than those on Rigaudella, have distal ring trabeculae, and few or none are interconnected by trabeculae.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Rigaudella Below, 1982b. Diagnosis from Below (1982b, p.138) Cysts are spheroidal, skolochorate, and ?two-layered. Solid and/or hollow, generally distally expanded, intratabular processes are connected to one another distally by solid trabeculae. Process formula follows the gonyaulacoid pattern 1-4`, 1-6", 0c, 0s, 2-5"' (2-6"'), pc, 1"'' , with only one process per paraplate. Archeopyle apical with compound operculum, type 4A.