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Wilsonidium modicum
Wilsonidinium modicum Iakovleva, 2016, p.20 (on PDF initially published online), pl.7, figs.10–11; text-fig.4b (part). Holotype: Iakovleva, 2016, pl.7, figs.10–11. Age: earliest Eocene.
Original description (Iakovleva, 2016)
Holotype: Plate 7, figures 10–11; slide MPA 62304-2; England Finder reference L9/3.
Type stratum and locality: Sample SMA 2-53, ∼13.0 m depth; Sotteville-sur-Mer Member; BRGM Scientific Borehole Siège-Madame-2, Dieppe-Hampshire Basin, France.
Diagnosis: A circumcavate species of Wilsonidium with sutural folds and lateral decoration by distally simple or bulbous outgrowths.
Description: A thin-walled, mid-sized circumcavate cyst with pentagonal outline and well-developed horns. The antapical horns are of about equal length. The endocyst is ovoidal with a slight expansion in the precingular area. The periphragm is thin, and is ornamented by sutural folds. Around the apical and precingular horns, the periphragm is decorated by outgrowths distally simple or bulbous. Endophragm is smooth. Archaeopyle is hyperepeliform, slightly extending into the epipericoel, operculum free.
Dimensions: Holotype: pericyst length 80 µm; pericyst width 71 µm; endocyst length 59 µm; endocyst 55 µm. Dimensions of measured specimens: pericyst length 76–80 µm (mean value 78 µm); pericyst width 71–74 µm (mean value 73 µm); endocyst length 58–59 µm (mean value 58.5 µm); endocyst width 50–55 µm (mean value 52.5 µm). Two specimens measured.
Comparison: Wilsonidium modicum differs from other species of the genus in having shorter horns, in its smaller size, in having the sutural ornamentation expressed by folds and in the ornamentation of lateral parts of the periphragm by outgrowths of variable size.
Stratigraphical range: Earliest Eocene.
Derivation of name: From the Latin modicum (small), meaning the relatively small size of this species.
Original description (Iakovleva, 2016)
Holotype: Plate 7, figures 10–11; slide MPA 62304-2; England Finder reference L9/3.
Type stratum and locality: Sample SMA 2-53, ∼13.0 m depth; Sotteville-sur-Mer Member; BRGM Scientific Borehole Siège-Madame-2, Dieppe-Hampshire Basin, France.
Diagnosis: A circumcavate species of Wilsonidium with sutural folds and lateral decoration by distally simple or bulbous outgrowths.
Description: A thin-walled, mid-sized circumcavate cyst with pentagonal outline and well-developed horns. The antapical horns are of about equal length. The endocyst is ovoidal with a slight expansion in the precingular area. The periphragm is thin, and is ornamented by sutural folds. Around the apical and precingular horns, the periphragm is decorated by outgrowths distally simple or bulbous. Endophragm is smooth. Archaeopyle is hyperepeliform, slightly extending into the epipericoel, operculum free.
Dimensions: Holotype: pericyst length 80 µm; pericyst width 71 µm; endocyst length 59 µm; endocyst 55 µm. Dimensions of measured specimens: pericyst length 76–80 µm (mean value 78 µm); pericyst width 71–74 µm (mean value 73 µm); endocyst length 58–59 µm (mean value 58.5 µm); endocyst width 50–55 µm (mean value 52.5 µm). Two specimens measured.
Comparison: Wilsonidium modicum differs from other species of the genus in having shorter horns, in its smaller size, in having the sutural ornamentation expressed by folds and in the ornamentation of lateral parts of the periphragm by outgrowths of variable size.
Stratigraphical range: Earliest Eocene.
Derivation of name: From the Latin modicum (small), meaning the relatively small size of this species.