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Alterbidinium rugulum
From Fensome et al., 2019:
Alterbidinium rugulum, Iakovleva and Kulkova, 2001, p.16, pl.8, figs.8,12–14; text-fig.10.
Holotype: Iakovleva and Kulkova, 2001, pl.8, figs.8,12–14.
Age: Early Eocene (Ypresian).
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Original description: [Iakovleva and Kulkova, 2001]:
Alterbidinium rugulum sp. nov.
Derivation of name. English, rugulate.
Holotype. - Slide No. Р-32-156.0-1 (Borehole No. 32, Pur Downstream Basin).
Diagnosis.-A species of Alterbidinium Lentin & Williams 1985 wich [sic] is characterised by rugulate surface of periphragm and endophragm. The cysts is circumcavate. The apical and antapical horns are reduced, and the antapical hornes are symmetrical. The peri-archaeopyle is of intercalary-precingular type. The paraplate 2a is hexa-thetaform.
Description. - The cysts is peridiniacean circumcavate; the periphragm and the endophragm are rugulate. The epicyst has a triangular shape; an apical horn is reduced with a truncated apex. The antapical horns are symmetrical and reduced. The paracingulum is clearly visible by elevations of periphragm. The endocyst is oval. The archaeopyle is intercalary-pre-is cingular of the type Ia(2a); the shape of pylome is hexa-thetaform.
Holotype dimensions. - Length of pericyst: 81.6 µm; width of pericyst: 63.7 µm; length of endocyst: 58.7 µm; width of endocyst: 51 µm; width of paracingulum: 7.65 µm.
Type Locality. - Borehole No. 32 (Pur Downstream Basin), depth 156.0 m, Irbitskaya Formation, Western Siberia.
Remarks - The species Alterbidinium rugulum differs from another species of genus Alterbidinium (especially Alterbidinium circulum) in the rounded shape, the rugulate surface of the wall and in the symmetry of the antapical horns.
Alterbidinium rugulum, Iakovleva and Kulkova, 2001, p.16, pl.8, figs.8,12–14; text-fig.10.
Holotype: Iakovleva and Kulkova, 2001, pl.8, figs.8,12–14.
Age: Early Eocene (Ypresian).
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Original description: [Iakovleva and Kulkova, 2001]:
Alterbidinium rugulum sp. nov.
Derivation of name. English, rugulate.
Holotype. - Slide No. Р-32-156.0-1 (Borehole No. 32, Pur Downstream Basin).
Diagnosis.-A species of Alterbidinium Lentin & Williams 1985 wich [sic] is characterised by rugulate surface of periphragm and endophragm. The cysts is circumcavate. The apical and antapical horns are reduced, and the antapical hornes are symmetrical. The peri-archaeopyle is of intercalary-precingular type. The paraplate 2a is hexa-thetaform.
Description. - The cysts is peridiniacean circumcavate; the periphragm and the endophragm are rugulate. The epicyst has a triangular shape; an apical horn is reduced with a truncated apex. The antapical horns are symmetrical and reduced. The paracingulum is clearly visible by elevations of periphragm. The endocyst is oval. The archaeopyle is intercalary-pre-is cingular of the type Ia(2a); the shape of pylome is hexa-thetaform.
Holotype dimensions. - Length of pericyst: 81.6 µm; width of pericyst: 63.7 µm; length of endocyst: 58.7 µm; width of endocyst: 51 µm; width of paracingulum: 7.65 µm.
Type Locality. - Borehole No. 32 (Pur Downstream Basin), depth 156.0 m, Irbitskaya Formation, Western Siberia.
Remarks - The species Alterbidinium rugulum differs from another species of genus Alterbidinium (especially Alterbidinium circulum) in the rounded shape, the rugulate surface of the wall and in the symmetry of the antapical horns.