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Petalodinium lenisium
Petalodinium lenisium Iakovleva, 2016, p.11 (on PDF initially published online), pl.7, figs.1–2; text-fig.4a (part).
Holotype: Iakovleva, 2016, pl.7, figs.1–2.
Age: earliest Eocene.
Type locality: Dieppe-Hampshire Basin, France.
Original description:
Diagnosis:
A circumcavate Petalodinium with reduced horns and a smooth periphragm.
Description:
A mid-sized, thin-walled circumcavate cyst with subdued pentagonal outline. Cornucavate to narrowly circumcavate.
Horns are reduced.
Periphragm: is thin, smooth; only the archaeopyle and cingular folds indicate the tabulation. The endocyst rounded, sometimes with slight lateral expansions; endophragm is thin.
Archaeopyle: latiepeliform with a free operculum.
Dimensions:
Holotype: pericyst length 78 µm; pericyst width 85 µm; endocyst length 61 µm; endocyst width 70 µm. Dimensions of measured specimens: pericyst length 62-84 µm (mean value 74 µm); pericyst width 70-87 µm (mean value 81 µm); endocyst width 70-75 µm (mean value 72 mm). Three specimens measured.
Comparison:
Petalodinium lenisium differs from the type species Petalodinium condylos by the smooth periphragm and the absence of the ornamentation expressed by a number of extremely short, blunt intratabular processes. This new species also differs from P. condylos, Petalodinium laszczynskii and Petalodinium rhomboideum in its smaller size (less than 90 µm) and having less developed horns.
Holotype: Iakovleva, 2016, pl.7, figs.1–2.
Age: earliest Eocene.
Type locality: Dieppe-Hampshire Basin, France.
Original description:
Diagnosis:
A circumcavate Petalodinium with reduced horns and a smooth periphragm.
Description:
A mid-sized, thin-walled circumcavate cyst with subdued pentagonal outline. Cornucavate to narrowly circumcavate.
Horns are reduced.
Periphragm: is thin, smooth; only the archaeopyle and cingular folds indicate the tabulation. The endocyst rounded, sometimes with slight lateral expansions; endophragm is thin.
Archaeopyle: latiepeliform with a free operculum.
Dimensions:
Holotype: pericyst length 78 µm; pericyst width 85 µm; endocyst length 61 µm; endocyst width 70 µm. Dimensions of measured specimens: pericyst length 62-84 µm (mean value 74 µm); pericyst width 70-87 µm (mean value 81 µm); endocyst width 70-75 µm (mean value 72 mm). Three specimens measured.
Comparison:
Petalodinium lenisium differs from the type species Petalodinium condylos by the smooth periphragm and the absence of the ornamentation expressed by a number of extremely short, blunt intratabular processes. This new species also differs from P. condylos, Petalodinium laszczynskii and Petalodinium rhomboideum in its smaller size (less than 90 µm) and having less developed horns.