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Stichodinium elegantulum
Stichodinium elegantulum Iakovleva, 2016, p.11,18 (on PDF initially published online), pl.7, figs.3,6,9; text-fig.4b (part).
Holotype: Iakovleva, 2016, pl.1, figs.4–5.
Age: earliest Eocene.
Original description (Iakovleva, 2016)
Diagnosis. A circumcavate species of Stichodinium with a pentagonal to subrounded-pentagonal outline, weakly developed horns and an ornamentation of narrow sutural folds.
Description. A thin-walled, mid-sized circumcavate to cornucavate cyst. The apical and lateral horns are reduced or absent, the antapical horns are short and of equal length or slightly unequal. Periphragm is thin and possesses narrow sutural folds, which in some cases appear to be slightly denticulate. Endophragm is thin and smooth. Archaeopyle is latiepeliform; operculum free, partially attached, or in place.
Dimensions.
Holotype: pericyst length 75 µm; pericyst width 76 µm; endocyst length 57 µm; endocyst width 65 µm. Paratype 1: pericyst length 91 µm; pericyst width 98 µm; endocyst length 74 µm; endocyst width 79 µm. Paratype 2: pericyst length 75 µm; pericyst width 83 µm; endocyst 58 µm; endocyst width 65 µm. Dimensions of measured specimens: pericyst length 67–91 µm (mean value 75 µm); pericyst width 74–98 µm (mean value 80 µm); endocyst length 51–74 µm (mean value 58 µm); endocyst width 57–79 µm (mean value 64 µm). Ten specimens measured.
Comparison. Stichodinium elegantulum differs from all described Stichodinium species in possessing narrow sutural folds, which define the tabulation. Stichodinium elegantulum is smaller than Stichodinium subtile and has a different outline.
Stratigraphical range. Earliest Eocene.
Derivation of name. From the Latin elegantulus, meaning very fine, in reference to the beautiful appearance of this species.
Holotype: Iakovleva, 2016, pl.1, figs.4–5.
Age: earliest Eocene.
Original description (Iakovleva, 2016)
Diagnosis. A circumcavate species of Stichodinium with a pentagonal to subrounded-pentagonal outline, weakly developed horns and an ornamentation of narrow sutural folds.
Description. A thin-walled, mid-sized circumcavate to cornucavate cyst. The apical and lateral horns are reduced or absent, the antapical horns are short and of equal length or slightly unequal. Periphragm is thin and possesses narrow sutural folds, which in some cases appear to be slightly denticulate. Endophragm is thin and smooth. Archaeopyle is latiepeliform; operculum free, partially attached, or in place.
Dimensions.
Holotype: pericyst length 75 µm; pericyst width 76 µm; endocyst length 57 µm; endocyst width 65 µm. Paratype 1: pericyst length 91 µm; pericyst width 98 µm; endocyst length 74 µm; endocyst width 79 µm. Paratype 2: pericyst length 75 µm; pericyst width 83 µm; endocyst 58 µm; endocyst width 65 µm. Dimensions of measured specimens: pericyst length 67–91 µm (mean value 75 µm); pericyst width 74–98 µm (mean value 80 µm); endocyst length 51–74 µm (mean value 58 µm); endocyst width 57–79 µm (mean value 64 µm). Ten specimens measured.
Comparison. Stichodinium elegantulum differs from all described Stichodinium species in possessing narrow sutural folds, which define the tabulation. Stichodinium elegantulum is smaller than Stichodinium subtile and has a different outline.
Stratigraphical range. Earliest Eocene.
Derivation of name. From the Latin elegantulus, meaning very fine, in reference to the beautiful appearance of this species.