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Tenua colliveri
From Fensome et al., 2019:
Tenua colliveri (Cookson and Eisenack, 1960b, p.251, pl.38, figs.3–4) Fensome et al., 2019a, p.47.
Holotype: Cookson and Eisenack, 1960b, pl.38, fig.4; Bint, 1986, text-fig.14E; Fensome et al., 2019a, fig.17T.
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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Comments Fensome et al., 2019a:
Cookson & Eisenack (1960, p. 251) noted that the thin autophragm is “… granular or closely to sparsely spinulate.” The illustration of the holotype (Cookson & Eisenack 1960, pl. 38, fig. 4) appears to show a relatively thick wall with predominantly and evenly granular ornamentation. The other illustrated specimen (pl. 38, fig. 3) appears to have a partially vermiculate ornamentation and may not be conspecific with the holotype. We transfer this species to Tenua because it has an overall cover of unit ornament.
Stratigraphical occurrence. The type material is from the Aptian of Queensland, Australia
Tenua colliveri (Cookson and Eisenack, 1960b, p.251, pl.38, figs.3–4) Fensome et al., 2019a, p.47.
Holotype: Cookson and Eisenack, 1960b, pl.38, fig.4; Bint, 1986, text-fig.14E; Fensome et al., 2019a, fig.17T.
Originally Canningia, subsequently Circulodinium, thirdly Canninginopsis, fourthly (and now) Tenua Eisenack.
Age: Aptian.
---------------------------------------------------------------------------------------------------
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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Comments Fensome et al., 2019a:
Cookson & Eisenack (1960, p. 251) noted that the thin autophragm is “… granular or closely to sparsely spinulate.” The illustration of the holotype (Cookson & Eisenack 1960, pl. 38, fig. 4) appears to show a relatively thick wall with predominantly and evenly granular ornamentation. The other illustrated specimen (pl. 38, fig. 3) appears to have a partially vermiculate ornamentation and may not be conspecific with the holotype. We transfer this species to Tenua because it has an overall cover of unit ornament.
Stratigraphical occurrence. The type material is from the Aptian of Queensland, Australia