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Circulodinium colliveri
From Fensome et al., 2019:
Circulodinium colliveri (Cookson and Eisenack, 1960b, p.251, pl.38, figs.3–4) Helby, 1987, p.324–325. Holotype: Cookson and Eisenack, 1960b, pl.38, fig.4; Fensome et al., 2019a, fig.17T. NOW Tenua Eisenack. Originally Canningia, subsequently Circulodinium, thirdly Canninginopsis, fourthly (and now) Tenua Eisenack. Age: Aptian.
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Original description as Canningia colliveri: [Cookson and Eisenack, 1960, p. 251]:
Description:
Shell with straight or rounded sides; apical projection not prominent, basal indentation clearly marked; a "girdle" is usually present slightly above the equator. Shell-membrane densely and irregular reticulate, the reticulum low, small-meshed and thick-walled.
Dimensions:
holotype - 107 µm long, 100 µm broad. Paratype 106 µm long, 90 µm broad.
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Supplemental description:
Mehrota and Sarjeant, 1987, p. 154:
Description:
Proximate cyst, cingulotabulate and lenticular, having a broad apical archaeopyle with a strongly zigzag margin. Antapex bilobate; the left lobe may bear a small horn (pl. 8, fig. 4).
Autophragm ornamented with granules that are isodiametric (less than 1 µm in diameter) and arranged in a regular manner. In addition the ornamentation sometimes also includes a few low spines (< 1 µm), distributed sparsely on the autoblast (pl. 8, fig. 4).
Cingulum suggested by flexures occupying the region of maximum cyst width.
Sulcus not developed, though notch is developed.
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From Fennsome et al., 2019a:
Remarks. The present material shows great variability in the degree of asymmetry and the development of antapical
lobes.
Occurrence. Circulodinium colliveri is present from 50 to 372 m in the Northumberland Formation section exposed
from the south-eastern coast northward to Collishaw Point.
Circulodinium colliveri (Cookson and Eisenack, 1960b, p.251, pl.38, figs.3–4) Helby, 1987, p.324–325. Holotype: Cookson and Eisenack, 1960b, pl.38, fig.4; Fensome et al., 2019a, fig.17T. NOW Tenua Eisenack. Originally Canningia, subsequently Circulodinium, thirdly Canninginopsis, fourthly (and now) Tenua Eisenack. Age: Aptian.
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Original description as Canningia colliveri: [Cookson and Eisenack, 1960, p. 251]:
Description:
Shell with straight or rounded sides; apical projection not prominent, basal indentation clearly marked; a "girdle" is usually present slightly above the equator. Shell-membrane densely and irregular reticulate, the reticulum low, small-meshed and thick-walled.
Dimensions:
holotype - 107 µm long, 100 µm broad. Paratype 106 µm long, 90 µm broad.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Supplemental description:
Mehrota and Sarjeant, 1987, p. 154:
Description:
Proximate cyst, cingulotabulate and lenticular, having a broad apical archaeopyle with a strongly zigzag margin. Antapex bilobate; the left lobe may bear a small horn (pl. 8, fig. 4).
Autophragm ornamented with granules that are isodiametric (less than 1 µm in diameter) and arranged in a regular manner. In addition the ornamentation sometimes also includes a few low spines (< 1 µm), distributed sparsely on the autoblast (pl. 8, fig. 4).
Cingulum suggested by flexures occupying the region of maximum cyst width.
Sulcus not developed, though notch is developed.
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From Fennsome et al., 2019a:
Remarks. The present material shows great variability in the degree of asymmetry and the development of antapical
lobes.
Occurrence. Circulodinium colliveri is present from 50 to 372 m in the Northumberland Formation section exposed
from the south-eastern coast northward to Collishaw Point.