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Heteraulacacysta
From Williams et al., 2017:
[Heteraulacacysta, Drugg and Loeblich Jr., 1967, p.183; Emendation: Bujak in Bujak et al., 1980, p. 58.
Type species: Heteraulacacysta campanula, Drugg and Loeblich, 1967 (pl.1, figs.8a–c)]
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Original description: [Drugg and Loeblich, 1967]:
Description:
Proximate fossil cyst with a cingular archeopyle. The epitract is bell-shaped, the hypotract is cup-shaped, and the transverse section is more or less circular. The tabulation is 3`, 7``, 5```, 3````. Plates 1`` and 7`` are commonly absent or weakly expressed.
Affinities:
This fossil genus is quite obviously related to the living genus Heteraulacus Diesing, 1850 (objective senior synonym of Goniodoma Stein, 1883) . The type species of our new genus bears a close resemblance to the living species Heteraulacus polyedricus (Pouchet) Drugg and Loeblich, comb. nov. (Basionym: Peridinium polyedricum Pouchet, 1883.).
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Modified description:
Stover and Evitt, 1978, p. 209:
Synopsis:
Cyts proximochorate, subspherical to subpolyhedral; outline circular, or nearly so, in apical-antapical view; paratabulation gonyaulacacean, indicated by parasutural features; combination epicystal archeopyle, Type (tAtP).
Description:
Shape: Subspherical to subpolyhedral; outline circular, or nearly so, in apical-antapical view.
Wall relationships: Endophragm and periphragm appressed except where latter forms parasutural folds or septa. Both wall layers thin.
Wall features: Parasutural folds or sepia smooth or faintly ornamented, as are areas between parasutural features.
Paratabulation: Indicated by parasutural features; gonyaulacacean, formula: 4`, 6``, Xc, 6```, 1p, 1````, 1ps.
Archeopyle: Combination epicystal archeopyle, Type (tAyP); principal archeopyle suture within paracingulum; constituent paraplates expressed on operculum.
Paracingulum: Indicated by two transverse parallel septa.
Parasulcus: Poorly indicated by ventral indentations in outline or by vaguely delimited depression on hypocyst, or both.
Size: Intermediate.
Remark:
The paratabulation on specimens of Heteraulacacysta is often difficult to interpret because of the thinness of the cyst walls, which are commonly folded and/or compressed. We interpret the form as having a gonyaulacacean paratabulation similar to that of the modern genus Pyrodinium. This interpretation differs somewhat from that of Drugg & Loeblich (1967), who used the modern genus Heteraulacus as a model for comparison, and explains the difference in our paratabulation formulas.
Affinities:
Heteraulacacysta differs from Dinopterygium in lacking intratabular clusters of wall features in the areas between parasutural folds or septa.
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Emended description:
Bujak in Bujak et al., 1980:
Diagnosis:
Cyst spherical, ovoidal, or discoidal, approximately circular in polar view.
Periphragm forming parasutural crests which delimit a paratabulation of 1pr, 1`*, 3`, 6``, xc, 5-6```, 1p, 1````, 1p.s. The first apical may or may not contact the preapical and second apical paraplates. Periphragm smooth, chagrinate, granulate, perforate, or echinate; never tuberculate. Paracingulum delimited by two parallel crests that are interrupted by the parasulcal furrow. Archaeopyle hemicystal.
For an extensive discussion see Bujak in Bujak et al., 1980, p. 58, 60.
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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.
Heteraulacacysta Drugg and Loeblich, Jr., 1967, emend. Bujak in Bujak et al., 1980, has a quinqueform hypocyst and an exsert to metasert 1`. The posterior sulcal homolog is external to the sulcus. The archeopyle is epicystal.
[Heteraulacacysta, Drugg and Loeblich Jr., 1967, p.183; Emendation: Bujak in Bujak et al., 1980, p. 58.
Type species: Heteraulacacysta campanula, Drugg and Loeblich, 1967 (pl.1, figs.8a–c)]
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Original description: [Drugg and Loeblich, 1967]:
Description:
Proximate fossil cyst with a cingular archeopyle. The epitract is bell-shaped, the hypotract is cup-shaped, and the transverse section is more or less circular. The tabulation is 3`, 7``, 5```, 3````. Plates 1`` and 7`` are commonly absent or weakly expressed.
Affinities:
This fossil genus is quite obviously related to the living genus Heteraulacus Diesing, 1850 (objective senior synonym of Goniodoma Stein, 1883) . The type species of our new genus bears a close resemblance to the living species Heteraulacus polyedricus (Pouchet) Drugg and Loeblich, comb. nov. (Basionym: Peridinium polyedricum Pouchet, 1883.).
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Modified description:
Stover and Evitt, 1978, p. 209:
Synopsis:
Cyts proximochorate, subspherical to subpolyhedral; outline circular, or nearly so, in apical-antapical view; paratabulation gonyaulacacean, indicated by parasutural features; combination epicystal archeopyle, Type (tAtP).
Description:
Shape: Subspherical to subpolyhedral; outline circular, or nearly so, in apical-antapical view.
Wall relationships: Endophragm and periphragm appressed except where latter forms parasutural folds or septa. Both wall layers thin.
Wall features: Parasutural folds or sepia smooth or faintly ornamented, as are areas between parasutural features.
Paratabulation: Indicated by parasutural features; gonyaulacacean, formula: 4`, 6``, Xc, 6```, 1p, 1````, 1ps.
Archeopyle: Combination epicystal archeopyle, Type (tAyP); principal archeopyle suture within paracingulum; constituent paraplates expressed on operculum.
Paracingulum: Indicated by two transverse parallel septa.
Parasulcus: Poorly indicated by ventral indentations in outline or by vaguely delimited depression on hypocyst, or both.
Size: Intermediate.
Remark:
The paratabulation on specimens of Heteraulacacysta is often difficult to interpret because of the thinness of the cyst walls, which are commonly folded and/or compressed. We interpret the form as having a gonyaulacacean paratabulation similar to that of the modern genus Pyrodinium. This interpretation differs somewhat from that of Drugg & Loeblich (1967), who used the modern genus Heteraulacus as a model for comparison, and explains the difference in our paratabulation formulas.
Affinities:
Heteraulacacysta differs from Dinopterygium in lacking intratabular clusters of wall features in the areas between parasutural folds or septa.
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Emended description:
Bujak in Bujak et al., 1980:
Diagnosis:
Cyst spherical, ovoidal, or discoidal, approximately circular in polar view.
Periphragm forming parasutural crests which delimit a paratabulation of 1pr, 1`*, 3`, 6``, xc, 5-6```, 1p, 1````, 1p.s. The first apical may or may not contact the preapical and second apical paraplates. Periphragm smooth, chagrinate, granulate, perforate, or echinate; never tuberculate. Paracingulum delimited by two parallel crests that are interrupted by the parasulcal furrow. Archaeopyle hemicystal.
For an extensive discussion see Bujak in Bujak et al., 1980, p. 58, 60.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Heteraulacacysta Drugg and Loeblich, Jr., 1967, emend. Bujak in Bujak et al., 1980, has a quinqueform hypocyst and an exsert to metasert 1`. The posterior sulcal homolog is external to the sulcus. The archeopyle is epicystal.