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Eurydinium euthemum
From Fensome et al., 2019:
Eurydinium euthemum (Davey and Verdier, 1971, p.40, pl.3, figs.1–3) Stover and Evitt, 1978, p.105. Holotype: Davey and Verdier, 1971, pl.3, fig.2. Originally Deflandrea, subsequently Subtilisphaera?, thirdly (and now) Eurydinium. Age: middle–late Albian.
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Original diagnosis: Davey and Verdier 1971, p. 40 (pl. 3, fig. 1-3): Deflandrea euthema
Cyst simple, thin walled, possessing spherical to ovoidal inner body, with hollow apical horn and antapical projection. Apical horn conical; antapical projection slightly asymmetrical, but definite horn(s) absent. Outer membrane smooth to slightly granular. Cingulum lightly defined. Archaeopyle occasionally discernible.
Dimensions Holotype Paratype Range
Overall length 74 µ; 49 µ; 48(54.3)74 µ
Overall width 33 µ; 38 µ; 32(37.3)48 µ
Original description: Davey and Verdier 1971, p. 40 (pl. 3, fig. 1-3): Deflandrea euthema
The antapical projection is angular, typically with one lateral side longer than the other (see plate 3, fig. 2). The archeopyle is sometimes present, but the operculum always remains attached along its apical border. Usually it more or less returns to its original position after excystment has taken place. This species, in the type material, does not stain with safranin.
Remarks: The simple form of D. euthema sp. nov. distinguishes it from all described species. The shape of the antapical projection is similar to some individuals belonging to the genus Ovoidinium Davey 1970, but archeopyle formation is different.
Eurydinium euthemum (Davey and Verdier, 1971, p.40, pl.3, figs.1–3) Stover and Evitt, 1978, p.105. Holotype: Davey and Verdier, 1971, pl.3, fig.2. Originally Deflandrea, subsequently Subtilisphaera?, thirdly (and now) Eurydinium. Age: middle–late Albian.
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Original diagnosis: Davey and Verdier 1971, p. 40 (pl. 3, fig. 1-3): Deflandrea euthema
Cyst simple, thin walled, possessing spherical to ovoidal inner body, with hollow apical horn and antapical projection. Apical horn conical; antapical projection slightly asymmetrical, but definite horn(s) absent. Outer membrane smooth to slightly granular. Cingulum lightly defined. Archaeopyle occasionally discernible.
Dimensions Holotype Paratype Range
Overall length 74 µ; 49 µ; 48(54.3)74 µ
Overall width 33 µ; 38 µ; 32(37.3)48 µ
Original description: Davey and Verdier 1971, p. 40 (pl. 3, fig. 1-3): Deflandrea euthema
The antapical projection is angular, typically with one lateral side longer than the other (see plate 3, fig. 2). The archeopyle is sometimes present, but the operculum always remains attached along its apical border. Usually it more or less returns to its original position after excystment has taken place. This species, in the type material, does not stain with safranin.
Remarks: The simple form of D. euthema sp. nov. distinguishes it from all described species. The shape of the antapical projection is similar to some individuals belonging to the genus Ovoidinium Davey 1970, but archeopyle formation is different.