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Stichodinium prostimum
Stichodinium prostimum Iakovleva, 2016, p.18–19 (on PDF initially published online), pl.7, figs.7–8; text-fig.4b (part). Holotype: Iakovleva, 2016, pl.7, figs.7–8. Age: earliest Eocene.
Original description (Iakovleva, 2016)
Diagnosis. A circumcavate species of Stichodinium with poorly developed horns and tubercles defining the tabulation.
Description. A thin-walled, mid-sized circumcavate cyst with (slightly rounded-) pentagonal outline. The apical horn is short and pointed; the left antapical horn is reduced. The periphragm is thin and ornamented by sutural rows of tubercles (sometimes united proximally). Endocyst is ovoidal; endophragm is smooth. Archaeopyle is latiepeliform with a free operculum.
Dimensions. Holotype: pericyst length 82 µm; pericyst width 78 µm; endocyst length 64 µm; endocyst width 63 µm.
Comparison. Stichodinium prostimus differs from Stichodinium subtile and Stichodinium? lineidentatum in being smaller and having less well developed horns, and in the outline of the pericyst. This is the only species of the genus Stichodinium in which the sutures are ornamented with tubercles.
Stratigraphical range. Earliest Eocene.
Derivation of name. From the Greek próstimo (small), in reference to small cysts of this species.
Original description (Iakovleva, 2016)
Diagnosis. A circumcavate species of Stichodinium with poorly developed horns and tubercles defining the tabulation.
Description. A thin-walled, mid-sized circumcavate cyst with (slightly rounded-) pentagonal outline. The apical horn is short and pointed; the left antapical horn is reduced. The periphragm is thin and ornamented by sutural rows of tubercles (sometimes united proximally). Endocyst is ovoidal; endophragm is smooth. Archaeopyle is latiepeliform with a free operculum.
Dimensions. Holotype: pericyst length 82 µm; pericyst width 78 µm; endocyst length 64 µm; endocyst width 63 µm.
Comparison. Stichodinium prostimus differs from Stichodinium subtile and Stichodinium? lineidentatum in being smaller and having less well developed horns, and in the outline of the pericyst. This is the only species of the genus Stichodinium in which the sutures are ornamented with tubercles.
Stratigraphical range. Earliest Eocene.
Derivation of name. From the Greek próstimo (small), in reference to small cysts of this species.