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Cribroperidinium scottii
From Fensome et al., 2019:
Cribroperidinium? scottii (Cookson and Eisenack, 1958, p.30, pl.2, figs.5–6) Helenes, 1984, p.131. Holotype: Cookson and Eisenack,
1958, pl.2, fig.5; Jan du Chêne et al., 1986a, pl.33, fig.5. Originally Gonyaulax (Appendix B), subsequently
Gonyaulacysta, thirdly Millioudodinium?, fourthly (and now) Cribroperidinium?. Questionable assignment:
Helenes (1984, p.130). Age: early to middle Kimmeridgian.
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Original description: Cookson and Eisenack, 1958, p. 30: Gonyaulax scottii
Theca variable in shape but mostly oval; epitheca dome-shaped with sharply delimited horn, hypotheca more rounded. Wall of theca thick, prolonged at intervals into short, blunt processes and ornamented, especially in the antapical region, by rather delicate processes that are sometimes free but more often confluent forming a loosely constructed or homogeneous membrane. The transverse girdle is narrow and generally obscured by the superficial membrane as frequently are the outlines of the plates.
The tabulation has not been exactly determined but in general conforms to that characterising the genus Gonyaulax.
Dimensions: Type 147x119 µm. Range 118-156x114-119 µm. Apical horn 21-24 µm.
Affinities:
Cookson and Eisenack, 1958, p. 30: Gonyaulax scottii
In its generall features Gonyaulax scottii agrees with the European Upper Jurassic species G. cladophora Defl. but differs in its rather more elongated form and more complex type of ornamentation. In G. cladophora the spiny outgrowths delimiting the plates and furrow are free from one another, whereas in G. scottii they are usually fused distally forming a delicate membrane.
Cribroperidinium? scottii (Cookson and Eisenack, 1958, p.30, pl.2, figs.5–6) Helenes, 1984, p.131. Holotype: Cookson and Eisenack,
1958, pl.2, fig.5; Jan du Chêne et al., 1986a, pl.33, fig.5. Originally Gonyaulax (Appendix B), subsequently
Gonyaulacysta, thirdly Millioudodinium?, fourthly (and now) Cribroperidinium?. Questionable assignment:
Helenes (1984, p.130). Age: early to middle Kimmeridgian.
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Original description: Cookson and Eisenack, 1958, p. 30: Gonyaulax scottii
Theca variable in shape but mostly oval; epitheca dome-shaped with sharply delimited horn, hypotheca more rounded. Wall of theca thick, prolonged at intervals into short, blunt processes and ornamented, especially in the antapical region, by rather delicate processes that are sometimes free but more often confluent forming a loosely constructed or homogeneous membrane. The transverse girdle is narrow and generally obscured by the superficial membrane as frequently are the outlines of the plates.
The tabulation has not been exactly determined but in general conforms to that characterising the genus Gonyaulax.
Dimensions: Type 147x119 µm. Range 118-156x114-119 µm. Apical horn 21-24 µm.
Affinities:
Cookson and Eisenack, 1958, p. 30: Gonyaulax scottii
In its generall features Gonyaulax scottii agrees with the European Upper Jurassic species G. cladophora Defl. but differs in its rather more elongated form and more complex type of ornamentation. In G. cladophora the spiny outgrowths delimiting the plates and furrow are free from one another, whereas in G. scottii they are usually fused distally forming a delicate membrane.