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Hystrichodinium isodiametricum
From Fensome et al., 2019:
Hystrichodinium isodiametricum (Cookson and Eisenack, 1958, p.38, pl.12, figs.11–12) Stover and Evitt, 1978, p.161. Holotype: Cookson and Eisenack, 1958, pl.12, figs.11–12. Originally Palaeohystrichophora, subsequently (and now) Hystrichodinium. Age: Campanian–early Maastrichtian.
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Locus typicus: Carnavron Basin, W Australia
Original description: Cookson and Eisenack, 1958, p. 38: Palaeohystrichophora isodiametrica
The shell is approximately isodiametric and divided somewhat unequally by a straight girdle with low borderes; both the epitheca and hypotheca are broadly dome-shaped to flat. The outer membrane, which is thin and transparent and lies close to the internal capsule, especially at the apex and antapex, is covered with numerous long wavy appendages. The example shown in pl.12, fig.11 has a large trapezoid shaped pylome which streches from just below the apex to the girdle.
Dimensions: Type 75x66 µm, girdle 6 µm, appendages c. 24 µm. Paratype 70x71 µm, girdle 5 µm, pylome 28x20 µm.
Affinities:
Cookson and Eisenack, 1958, p. 38: Palaeohystrichophora isodiametrica
In the type of ornamentation, Palaeohystrichophora isodiametrica resembles P. infusorioides Defl., but differs from this species in being approximately as along as broad and in having broadly rounded apicrs and somewhat longer appendages. In P. infusorioides as preserved in the Gearle Siltstone, the shell is fusiform and the appeandages are somewhat shorter and stiffer.
Hystrichodinium isodiametricum (Cookson and Eisenack, 1958, p.38, pl.12, figs.11–12) Stover and Evitt, 1978, p.161. Holotype: Cookson and Eisenack, 1958, pl.12, figs.11–12. Originally Palaeohystrichophora, subsequently (and now) Hystrichodinium. Age: Campanian–early Maastrichtian.
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Locus typicus: Carnavron Basin, W Australia
Original description: Cookson and Eisenack, 1958, p. 38: Palaeohystrichophora isodiametrica
The shell is approximately isodiametric and divided somewhat unequally by a straight girdle with low borderes; both the epitheca and hypotheca are broadly dome-shaped to flat. The outer membrane, which is thin and transparent and lies close to the internal capsule, especially at the apex and antapex, is covered with numerous long wavy appendages. The example shown in pl.12, fig.11 has a large trapezoid shaped pylome which streches from just below the apex to the girdle.
Dimensions: Type 75x66 µm, girdle 6 µm, appendages c. 24 µm. Paratype 70x71 µm, girdle 5 µm, pylome 28x20 µm.
Affinities:
Cookson and Eisenack, 1958, p. 38: Palaeohystrichophora isodiametrica
In the type of ornamentation, Palaeohystrichophora isodiametrica resembles P. infusorioides Defl., but differs from this species in being approximately as along as broad and in having broadly rounded apicrs and somewhat longer appendages. In P. infusorioides as preserved in the Gearle Siltstone, the shell is fusiform and the appeandages are somewhat shorter and stiffer.