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Tenua attadalica
From Fensome et al., 2019:
Tenua? attadalica (Cookson and Eisenack, 1962b, p.495, pl.5, figs.12–15) Fensome et al., 2019a, p.46.
Holotype: Cookson and Eisenack, 1962b, pl.5, fig.13; Fensome et al., 2019a, fig.17R.
Originally Cyclonephelium?, subsequently Aptea, thirdly Canningia, fourthly Circulodinium, fifthly (and now) Tenua Eisenack.
Questionable assignment: Fensome et al. (2019a. p.46).
Age: Aptian–Albian.
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Original description as Cyclonephelium attadalicum: [Cookson and Eisenack, 1962, p. 495]:
Description:
Shell small, slightly biconvex, more or less polygonal in outline with a broadly indented base, one of the basal projections being more prominent than the other.
Surface ornamented with small, stiff, frequently capitate appandages which tend to be grouped in intervals around the shell, especially in the antapical region. The central portions of both surfaces are relatively free from appandages except in the equatorial region of one surface, which, in well-preserved examples, is crossed by two rows of appandages that appear to delimit a girdle like zone. Usually, on the opposite surface a slight deepening runs from the limits of the girdle zone to the antapex.
No complete specimens have been observed, but it is clear that the shells opened by the detachment of the apex along a nearly straight or zig-zag line.
Dimensions:
Holotype: overall width 82 µm, width of shell 72 µm, range: overall width 70-80 µm, width of shell 60-77 µm.
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Comments Fensome et al., 2019a:
Cookson & Eisenack (1962, p. 495) commented:
Surface ornamented with small, stiff, frequently capitate appendages which tend to be grouped at intervals around the shell, especially in the antapical region. The central portions of both surfaces are relatively free from appendages except in the equatorial region of one surface, which … is crossed by two rows of appendages that appear to delimit a girdle-like zone [i.e. the cingulum].
In terms of our generic criteria, this species is difficult to interpret, especially the holotype. As Cookson & Eisenack (1962) indicated, the spines seem to be clumped, and the dorsal and ventral surfaces have relatively sparse ornamentation. However, the holotype appears to have a clump of processes in the dorsoventral area. Given this uncertainty, we questionably transfer this species to Tenua.
Stratigraphical occurrence. The type material of this species is from the Aptian and Albian of Australia.
Tenua? attadalica (Cookson and Eisenack, 1962b, p.495, pl.5, figs.12–15) Fensome et al., 2019a, p.46.
Holotype: Cookson and Eisenack, 1962b, pl.5, fig.13; Fensome et al., 2019a, fig.17R.
Originally Cyclonephelium?, subsequently Aptea, thirdly Canningia, fourthly Circulodinium, fifthly (and now) Tenua Eisenack.
Questionable assignment: Fensome et al. (2019a. p.46).
Age: Aptian–Albian.
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Original description as Cyclonephelium attadalicum: [Cookson and Eisenack, 1962, p. 495]:
Description:
Shell small, slightly biconvex, more or less polygonal in outline with a broadly indented base, one of the basal projections being more prominent than the other.
Surface ornamented with small, stiff, frequently capitate appandages which tend to be grouped in intervals around the shell, especially in the antapical region. The central portions of both surfaces are relatively free from appandages except in the equatorial region of one surface, which, in well-preserved examples, is crossed by two rows of appandages that appear to delimit a girdle like zone. Usually, on the opposite surface a slight deepening runs from the limits of the girdle zone to the antapex.
No complete specimens have been observed, but it is clear that the shells opened by the detachment of the apex along a nearly straight or zig-zag line.
Dimensions:
Holotype: overall width 82 µm, width of shell 72 µm, range: overall width 70-80 µm, width of shell 60-77 µm.
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Comments Fensome et al., 2019a:
Cookson & Eisenack (1962, p. 495) commented:
Surface ornamented with small, stiff, frequently capitate appendages which tend to be grouped at intervals around the shell, especially in the antapical region. The central portions of both surfaces are relatively free from appendages except in the equatorial region of one surface, which … is crossed by two rows of appendages that appear to delimit a girdle-like zone [i.e. the cingulum].
In terms of our generic criteria, this species is difficult to interpret, especially the holotype. As Cookson & Eisenack (1962) indicated, the spines seem to be clumped, and the dorsal and ventral surfaces have relatively sparse ornamentation. However, the holotype appears to have a clump of processes in the dorsoventral area. Given this uncertainty, we questionably transfer this species to Tenua.
Stratigraphical occurrence. The type material of this species is from the Aptian and Albian of Australia.