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Epelidinium brinkhuisii
Epelidinium brinkhuisii Iakovleva, 2016, p.5,7–8 (on PDF initially published online), pl.2, figs.3–4; pl.4, figs.7–9,13; pl.5, figs.7–9,10,14; text-fig.4a (part).
Holotype: Iakovleva, 2016, pl.5, figs.7–9.
Age: earliest Eocene.
Original description (Iakovleva, 2016):
Epelidinium brinkhuisii sp. nov. Plate 2, figures 3, 4; Plate 4, figures 7 9, 13; Plate 5, figures 7 9, 10, 14; Figure 4a
Synonymy. Apectodinium sp. A in Iakovleva et al., 2001, pl. I, fig. 1 5.
Holotype. Plate 5, figures 7 9; slide Sokolovsky-24-W; England Finder reference J39/1.
Paratype. Plate 2, figures 3 4; slide Sokolovsky-24-3; England Finder reference H46/2.
Type stratum and locality. Polosataya Formation, Sokolovsky Quarry, northern Kazakhstan, sample 24; earliest Eocene.
Diagnosis. A circumcavate species of Epelidinium with a pentagonal pericyst bearing conae.
Description. A thin-walled pentagonal circumcavate cyst. Apical, lateral and antapical horns are reduced, with the apical being truncate. Periphragm is thin and ornamented by conical protrusions or very short bifid processes that are not aligned. The cingulum is slightly delineated by discontinuous ridges. Endocyst is extremely thin and difficult to differentiate. Archaeopyle latiepeliform to equiepeliform; operculum in place, partially attached or free.
Dimensions. Holotype: pericyst length 104 µm; pericyst width 108 µm; endocyst length 73 µm; endocyst width 87 µm. Paratype: pericyst length 98 µm; pericyst width 101 µm. Dimensions of measured specimens: pericyst length 100-120 µm (mean value 106 µm); pericyst width 94-126 µm (mean value 105 µm); endocyst length 73-88 µm (mean value 82 µm); endocyst width 86-103 µm (mean value 92 µm). Six specimens measured.
Comparison and remarks. Epelidinium brinkhuisii differs from other Epelidinium species in having reduced horns and randomly distributed conical protrusions on the periphragm. Several observed specimens of Epelidinium brinkhuisii (Plate 4, figures 7 9) are transitional to Epelidinium leptotoichum, exhibiting fewer conical protrusions. A few (2 3) specimens of Epelidinium brinkhuisii demonstrate the transition to the latiepeliform archaeopyle, but most of the observed specimens are equiepeliform.
Stratigraphical range. Earliest Eocene.
Derivation of name. In honour of the Dutch palynologist Henk Brinkhuis.
Holotype: Iakovleva, 2016, pl.5, figs.7–9.
Age: earliest Eocene.
Original description (Iakovleva, 2016):
Epelidinium brinkhuisii sp. nov. Plate 2, figures 3, 4; Plate 4, figures 7 9, 13; Plate 5, figures 7 9, 10, 14; Figure 4a
Synonymy. Apectodinium sp. A in Iakovleva et al., 2001, pl. I, fig. 1 5.
Holotype. Plate 5, figures 7 9; slide Sokolovsky-24-W; England Finder reference J39/1.
Paratype. Plate 2, figures 3 4; slide Sokolovsky-24-3; England Finder reference H46/2.
Type stratum and locality. Polosataya Formation, Sokolovsky Quarry, northern Kazakhstan, sample 24; earliest Eocene.
Diagnosis. A circumcavate species of Epelidinium with a pentagonal pericyst bearing conae.
Description. A thin-walled pentagonal circumcavate cyst. Apical, lateral and antapical horns are reduced, with the apical being truncate. Periphragm is thin and ornamented by conical protrusions or very short bifid processes that are not aligned. The cingulum is slightly delineated by discontinuous ridges. Endocyst is extremely thin and difficult to differentiate. Archaeopyle latiepeliform to equiepeliform; operculum in place, partially attached or free.
Dimensions. Holotype: pericyst length 104 µm; pericyst width 108 µm; endocyst length 73 µm; endocyst width 87 µm. Paratype: pericyst length 98 µm; pericyst width 101 µm. Dimensions of measured specimens: pericyst length 100-120 µm (mean value 106 µm); pericyst width 94-126 µm (mean value 105 µm); endocyst length 73-88 µm (mean value 82 µm); endocyst width 86-103 µm (mean value 92 µm). Six specimens measured.
Comparison and remarks. Epelidinium brinkhuisii differs from other Epelidinium species in having reduced horns and randomly distributed conical protrusions on the periphragm. Several observed specimens of Epelidinium brinkhuisii (Plate 4, figures 7 9) are transitional to Epelidinium leptotoichum, exhibiting fewer conical protrusions. A few (2 3) specimens of Epelidinium brinkhuisii demonstrate the transition to the latiepeliform archaeopyle, but most of the observed specimens are equiepeliform.
Stratigraphical range. Earliest Eocene.
Derivation of name. In honour of the Dutch palynologist Henk Brinkhuis.