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Yalkalpodinium areolatum
From Fensome et al., 2019:
Yalkalpodinium areolatum (Cookson and Eisenack, 1960b, p.253, pl.38, figs.7–8) Morgan, 1980, p.34.
Holotype: Cookson and Eisenack, 1960b, pl.38, fig.8.
Taxonomic senior synonym: Canningia reticulata, according to Fensome et al. (2019a, p.29).
Originally Cyclonephelium, subsequently Yalkalpodinium.
Age: Tithonian.
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Locus typicus: Canning Basin, Western Australia
Stratum typicum: Tithonian
Original description: Cookson and Eisenack, 1960:
Shell flat, circular or slightly oval in outline with a peripheral sculptured zone (c. 15-20 µm broad) on both sides, in the form of a thin, finely vermiculate or areolate membrane; the unsculptured portion of the shell is generally smooth. A transverse "girdle" is usually present. A pylome is formed by the detachment of the apical region.
Dimensions:
Holotype: 70 µm long, 62 µm broad. Range: 57-90x62-74 µm.
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Emended description: Pocock, 1972:
Vesicle circular to oval; dorso-ventrally flattened; wall two-layered; inner layer less than 0.5 µm. thick; granulose; forming a more or less circular internal cyst; overlain by a transparent, finely granulose to smooth, outer layer 0.5-1.5 µm thick; peripheral zone 12.0-20.0 µm wide; infrareticulate; brocci rounded, about 3.0 µm wide; transverse furrow 16.0 µm wide, usually visible; epitheca terminated by a very reduced apical horn 3.5-5.0 µm long; hypotheca smoothly rounded; no horns developed; colour pale yellow; length of theca 96.8 µm; width of theca 83.6 µm; length of capsule 88.0 µm; width of capsule 73.7 µm.
Affinities:
The Canadian specimens are slightly larger than those described by Cookson and Eisenack, but in others respects are very similar. The "vermiculate or areolate" membrane described by the above authors is clearly seen on the Canadian specimens to be an internally reticulate structure.
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Yalkalpodinium areolatum (Cookson and Eisenack, 1960b, p.253, pl.38, figs.7–8) Morgan, 1980, p.34.
Holotype: Cookson and Eisenack, 1960b, pl.38, fig.8.
Taxonomic senior synonym: Canningia reticulata, according to Fensome et al. (2019a, p.29).
Originally Cyclonephelium, subsequently Yalkalpodinium.
Age: Tithonian.
----------------------------------------------------------------------------------------------------------------------------------
Locus typicus: Canning Basin, Western Australia
Stratum typicum: Tithonian
Original description: Cookson and Eisenack, 1960:
Shell flat, circular or slightly oval in outline with a peripheral sculptured zone (c. 15-20 µm broad) on both sides, in the form of a thin, finely vermiculate or areolate membrane; the unsculptured portion of the shell is generally smooth. A transverse "girdle" is usually present. A pylome is formed by the detachment of the apical region.
Dimensions:
Holotype: 70 µm long, 62 µm broad. Range: 57-90x62-74 µm.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description: Pocock, 1972:
Vesicle circular to oval; dorso-ventrally flattened; wall two-layered; inner layer less than 0.5 µm. thick; granulose; forming a more or less circular internal cyst; overlain by a transparent, finely granulose to smooth, outer layer 0.5-1.5 µm thick; peripheral zone 12.0-20.0 µm wide; infrareticulate; brocci rounded, about 3.0 µm wide; transverse furrow 16.0 µm wide, usually visible; epitheca terminated by a very reduced apical horn 3.5-5.0 µm long; hypotheca smoothly rounded; no horns developed; colour pale yellow; length of theca 96.8 µm; width of theca 83.6 µm; length of capsule 88.0 µm; width of capsule 73.7 µm.
Affinities:
The Canadian specimens are slightly larger than those described by Cookson and Eisenack, but in others respects are very similar. The "vermiculate or areolate" membrane described by the above authors is clearly seen on the Canadian specimens to be an internally reticulate structure.
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