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Canningia crassimarginata
From Fensome et al., 2019:
Canningia crassimarginata (Cookson and Eisenack, 1974, p.74–75, pl.28, figs.1–4) Fensome et al., 2019a, p.22.
Holotype: Cookson and Eisenack, 1974, pl.28, fig.3; Fensome et al., 2019a, fig.12I.
Originally Cyclonephelium, subsequently (and now) Canningia.
Age: middle Cretaceous.
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Cyclonephelium crassimarginatum Cookson and Eisenack, 1974
Holotype: Cookson and Eisenack, 1974, pl.28, fig.3
Age: Middle Cretaceous
Original diagnosis: Cookson and Eisenack, 1974, p.74-75
A Cyclonephelium-species with more or less thickened margin, and with fairly sturdy, radially directed, but irregularly developed and arranged supports, which support a more or less broad membrane with a continuous and smooth margin.As in the case of the Cyclonephelium-species, the base of the supports still lies on the flat sides of the shell in the vicinity of the margin, so that the supports come from both sides; accordingly the membrane is double, a phenomenon which is, however, only difficult to recognize. The surface of the shell is more or less distinctly granular.
Dimensions and occurrence: Type about 94 µm broad. The breadth of the remaining specimens lies between about 94 and 114 µm.
The specimens stem from the Gingin Brook bore from a region comprised between 404-414 ft. (Figure 1 ) and from the Balcatta bore, 240 ft.
Remarks: Cookson and Eisenack, 1974, p.75
The structure of the membrane is best recognized in case of injuries; in Figure 1, the specimen is slightly laterally compressed.
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Comments Fensome et al., 2019a:
Cookson and Eisenack (Citation1974, p. 74–75) provided the following diagnosis for this species:
A species of Cyclonephelium with a more or less strongly rounded border, with perpendicular [?], strong, radial, but irregularly structured and arranged supports, which are covered and connected by a more or less wide, smooth bordering membrane. As usual with Cyclonephelium species, the base of the supports originate around the margin on both of the flat sides of the shell; the membrane is thus double, which of course is difficult to discern. The surface of the shell is distinctly granular.
The presence of an outer wall layer (periphragm) and relatively densely arranged supporting structures indicates that this species belongs in Canningia rather than Cyclonephelium, and we effect the transfer here. The periphragm and supporting processes appear to be restricted to peripheral areas.
Stratigraphical occurrence. Cookson and Eisenack (Citation1974) described this species from the middle Cretaceous of Australia.
Canningia crassimarginata (Cookson and Eisenack, 1974, p.74–75, pl.28, figs.1–4) Fensome et al., 2019a, p.22.
Holotype: Cookson and Eisenack, 1974, pl.28, fig.3; Fensome et al., 2019a, fig.12I.
Originally Cyclonephelium, subsequently (and now) Canningia.
Age: middle Cretaceous.
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Cyclonephelium crassimarginatum Cookson and Eisenack, 1974
Holotype: Cookson and Eisenack, 1974, pl.28, fig.3
Age: Middle Cretaceous
Original diagnosis: Cookson and Eisenack, 1974, p.74-75
A Cyclonephelium-species with more or less thickened margin, and with fairly sturdy, radially directed, but irregularly developed and arranged supports, which support a more or less broad membrane with a continuous and smooth margin.As in the case of the Cyclonephelium-species, the base of the supports still lies on the flat sides of the shell in the vicinity of the margin, so that the supports come from both sides; accordingly the membrane is double, a phenomenon which is, however, only difficult to recognize. The surface of the shell is more or less distinctly granular.
Dimensions and occurrence: Type about 94 µm broad. The breadth of the remaining specimens lies between about 94 and 114 µm.
The specimens stem from the Gingin Brook bore from a region comprised between 404-414 ft. (Figure 1 ) and from the Balcatta bore, 240 ft.
Remarks: Cookson and Eisenack, 1974, p.75
The structure of the membrane is best recognized in case of injuries; in Figure 1, the specimen is slightly laterally compressed.
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Comments Fensome et al., 2019a:
Cookson and Eisenack (Citation1974, p. 74–75) provided the following diagnosis for this species:
A species of Cyclonephelium with a more or less strongly rounded border, with perpendicular [?], strong, radial, but irregularly structured and arranged supports, which are covered and connected by a more or less wide, smooth bordering membrane. As usual with Cyclonephelium species, the base of the supports originate around the margin on both of the flat sides of the shell; the membrane is thus double, which of course is difficult to discern. The surface of the shell is distinctly granular.
The presence of an outer wall layer (periphragm) and relatively densely arranged supporting structures indicates that this species belongs in Canningia rather than Cyclonephelium, and we effect the transfer here. The periphragm and supporting processes appear to be restricted to peripheral areas.
Stratigraphical occurrence. Cookson and Eisenack (Citation1974) described this species from the middle Cretaceous of Australia.