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Shublikodinium
From Williams et al., 2017:
[Shublikodinium, Wiggins, 1973, p. 2–4; Emendation: Stover and Helby, 1987a, p. 17-20, 118–119, as a revised description.
Type species: Shublikodinium arcticum, Wiggins, 1973 (pl.1, figs.1–2)]
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Original description: {Wiggins, 1973]:
Diagnosis:
Proximate fossil cysts; ambitus ovoidal. Epitract and hypotract approximately equal, divided by a distinct transverse furrow. Apical and antapical horns or inflations three in number; two in the antapical region, of which one is commonly reduced in attenuation. The sutural tabulation series is 1va.cl., 6`, 5a, 7", ?c, 7```, 1ppl., 3````, plus 5 sulcal platelets (?), where 1va.cl. is a ventral apical closing plate of the preapical series.
The archeopyle is Type A+5I, and the operculum is composed of the entire 1va.cl., 6`, 5a sutural tabulation series.
Sutural structures are indicated by a variety of cyst wall extensions, including spines and ridges, and cyst wall grooves or rupture lines. Ornamentation is variable. Norian strata whereas Rhaetogonyaulax is seldom found below the Rhaetian.
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Revised/Supplemental description:
Stover and Helby, 1987:
Synopsis:
Cysts proximate, ellipsoidal to biconical, and with or without antapical lobation; autophragm smooth or variously ornamented with nontabular, intratabular and or parasutural features or combination thereof; paratabulation rhaetogonyaulacacean, 1-2pr, 6`, 5a, 7", Xc,7```, 3````, 2-3s, and ppl, rarely expressed completely; archeopyle intercalary, type I to 5I.
Description:
Shape: Ovoidal to ellipsoidal with low, rounded or slightly pointed apical horn and rounded antapex which may be interrupted by 1 or 2 antapical lobes.
Wall relationships: Autophragm only.
WaII features: Parasutural features of low smooth or ornamented ridges, discontinuous rows of granules, or other solid features of low to moderate relief.
Paratabulation: Usually incompletely expressed by one or more of the archeopyle, the paracingulum and parasulcus, vague pandasutural areas, or by variably developed parasutural features. Paratabulation formula: 1-2pr, 6`, 5a, 7". Xc. 7```, 3```` , 2-3s and DDI. Paratabulation generally indicated more clearly on epicyst than on hypocyst, particularly in the precingular and anterior intercalary series.
Archeopyle: Intercalary, type I-5I; operculum free, usually as separate pieces. Mechanical attrition may result in loss of the apical series.
Paracingulum: Indicated by low to moderate transverse, parallel, equatorial ridges separated by a broad, shallow to deep concavity. Ends clearly offset, diverging markedly as they approach the parasulcus.
Parasulcus: Indicated by marked offset in paracingulum, commonly delimited by marginal ridges, frequently occurring as shallow, concave depression on ventral surface- may be subdivided.
Size: Intermediate.
Affinities:
Rhaetogonyaulax is differentiated from Shublikodinium by the attenuated apical horn and occurrence of a prominent antapical horn on the former. Extension of the broad, indented, parasulcus almost to the antapex of Shublikodinium may result in gentle lobation of the antapex. Sverdrupiella Bujak & Fisher 1976 is generally bicavate and is characterized by apical and antapical horns. Sverdrupiella may have up to 10 precingular paraplates, and 4 series of paraplates anterior of the paracingulum. Sahulidinium, in contrast to Shublikodinium, is larger, lacks apical or antapical horns, has 6 intercalary paraplates and a large, anteriorly gabled 7`` paraplate.
[Shublikodinium, Wiggins, 1973, p. 2–4; Emendation: Stover and Helby, 1987a, p. 17-20, 118–119, as a revised description.
Type species: Shublikodinium arcticum, Wiggins, 1973 (pl.1, figs.1–2)]
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Original description: {Wiggins, 1973]:
Diagnosis:
Proximate fossil cysts; ambitus ovoidal. Epitract and hypotract approximately equal, divided by a distinct transverse furrow. Apical and antapical horns or inflations three in number; two in the antapical region, of which one is commonly reduced in attenuation. The sutural tabulation series is 1va.cl., 6`, 5a, 7", ?c, 7```, 1ppl., 3````, plus 5 sulcal platelets (?), where 1va.cl. is a ventral apical closing plate of the preapical series.
The archeopyle is Type A+5I, and the operculum is composed of the entire 1va.cl., 6`, 5a sutural tabulation series.
Sutural structures are indicated by a variety of cyst wall extensions, including spines and ridges, and cyst wall grooves or rupture lines. Ornamentation is variable. Norian strata whereas Rhaetogonyaulax is seldom found below the Rhaetian.
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Revised/Supplemental description:
Stover and Helby, 1987:
Synopsis:
Cysts proximate, ellipsoidal to biconical, and with or without antapical lobation; autophragm smooth or variously ornamented with nontabular, intratabular and or parasutural features or combination thereof; paratabulation rhaetogonyaulacacean, 1-2pr, 6`, 5a, 7", Xc,7```, 3````, 2-3s, and ppl, rarely expressed completely; archeopyle intercalary, type I to 5I.
Description:
Shape: Ovoidal to ellipsoidal with low, rounded or slightly pointed apical horn and rounded antapex which may be interrupted by 1 or 2 antapical lobes.
Wall relationships: Autophragm only.
WaII features: Parasutural features of low smooth or ornamented ridges, discontinuous rows of granules, or other solid features of low to moderate relief.
Paratabulation: Usually incompletely expressed by one or more of the archeopyle, the paracingulum and parasulcus, vague pandasutural areas, or by variably developed parasutural features. Paratabulation formula: 1-2pr, 6`, 5a, 7". Xc. 7```, 3```` , 2-3s and DDI. Paratabulation generally indicated more clearly on epicyst than on hypocyst, particularly in the precingular and anterior intercalary series.
Archeopyle: Intercalary, type I-5I; operculum free, usually as separate pieces. Mechanical attrition may result in loss of the apical series.
Paracingulum: Indicated by low to moderate transverse, parallel, equatorial ridges separated by a broad, shallow to deep concavity. Ends clearly offset, diverging markedly as they approach the parasulcus.
Parasulcus: Indicated by marked offset in paracingulum, commonly delimited by marginal ridges, frequently occurring as shallow, concave depression on ventral surface- may be subdivided.
Size: Intermediate.
Affinities:
Rhaetogonyaulax is differentiated from Shublikodinium by the attenuated apical horn and occurrence of a prominent antapical horn on the former. Extension of the broad, indented, parasulcus almost to the antapex of Shublikodinium may result in gentle lobation of the antapex. Sverdrupiella Bujak & Fisher 1976 is generally bicavate and is characterized by apical and antapical horns. Sverdrupiella may have up to 10 precingular paraplates, and 4 series of paraplates anterior of the paracingulum. Sahulidinium, in contrast to Shublikodinium, is larger, lacks apical or antapical horns, has 6 intercalary paraplates and a large, anteriorly gabled 7`` paraplate.