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Endoscrinium attadalense
From Fensome et al., 2019:
Endoscrinium attadalense (Cookson and Eisenack, 1958, p.25, pl.1, fig.7) Riding and Fensome, 2002, p.21. Holotype: Cookson and Eisenack, 1958, pl.1, fig.7; Jan du Chêne et al., 1986a, pl.112, figs.4–7; Riding and Fensome, 2002, text-fig.4B.
Originally Gymnodinium (Appendix B), subsequently Scriniodinium, thirdly (and now) Endoscrinium. Riding and Fensome (2002, p.21) cited the basionym as Scriniodinium attadalense rather than Gymnodinium attadalense, but otherwise fully referenced the basionym; hence, their validation of the combination is accepted here. Age: Aptian.
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Original description (Cookson and Eisenack, 1958):
Gymnodinium attadalense sp. nov.
(PI. I, fig. 7; holotype)
Age and occurrence. Lower Cretaceous (? Aptian) : South Perth Formation, W.A., Attadale Bore at 809 ft.
Description. The test has a rather squarish outline with almost straight to convex sides and is divided unequally by a shallow transverse girdle into a slightly shorter and broader epitheca and a longer and somewhat pointed hypotheca.
The capsule follows the outline of the test but does not fill its cavity, a margin of about 11 μ being left around it. In the type the antapex of the capsule seems to be open, as does the membrane of the test directly opposite to it. However, this feature has not been evident in the three other examples of G. attadalense in the present collection. The outer membrane and membrane of the capsule are very faintly granular to smooth. A large pylome is developed in the epitheca.
Dimensions. Type 81 μ x 81 μ, capsule 59 μ x 59 μ.
Comments. G. attadalense is of the same general type as the Jurassic species G. crystallinum, G. luridum and G. parvimarginatum, but differs from all in the shape of the test.
These four species, in having flattened shells with thin margins, central capsules and conspicuous pylomes are distinct from such true fossil Gymnodinia as Gymnodinium cretaceum Defl., G. heterecostatum Defl. and G. nelsonense Cookson. It seems probable, therefore, that eventually they will be removed from the genus Gymnodinium. See Appendix 1.
Endoscrinium attadalense (Cookson and Eisenack, 1958, p.25, pl.1, fig.7) Riding and Fensome, 2002, p.21. Holotype: Cookson and Eisenack, 1958, pl.1, fig.7; Jan du Chêne et al., 1986a, pl.112, figs.4–7; Riding and Fensome, 2002, text-fig.4B.
Originally Gymnodinium (Appendix B), subsequently Scriniodinium, thirdly (and now) Endoscrinium. Riding and Fensome (2002, p.21) cited the basionym as Scriniodinium attadalense rather than Gymnodinium attadalense, but otherwise fully referenced the basionym; hence, their validation of the combination is accepted here. Age: Aptian.
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Original description (Cookson and Eisenack, 1958):
Gymnodinium attadalense sp. nov.
(PI. I, fig. 7; holotype)
Age and occurrence. Lower Cretaceous (? Aptian) : South Perth Formation, W.A., Attadale Bore at 809 ft.
Description. The test has a rather squarish outline with almost straight to convex sides and is divided unequally by a shallow transverse girdle into a slightly shorter and broader epitheca and a longer and somewhat pointed hypotheca.
The capsule follows the outline of the test but does not fill its cavity, a margin of about 11 μ being left around it. In the type the antapex of the capsule seems to be open, as does the membrane of the test directly opposite to it. However, this feature has not been evident in the three other examples of G. attadalense in the present collection. The outer membrane and membrane of the capsule are very faintly granular to smooth. A large pylome is developed in the epitheca.
Dimensions. Type 81 μ x 81 μ, capsule 59 μ x 59 μ.
Comments. G. attadalense is of the same general type as the Jurassic species G. crystallinum, G. luridum and G. parvimarginatum, but differs from all in the shape of the test.
These four species, in having flattened shells with thin margins, central capsules and conspicuous pylomes are distinct from such true fossil Gymnodinia as Gymnodinium cretaceum Defl., G. heterecostatum Defl. and G. nelsonense Cookson. It seems probable, therefore, that eventually they will be removed from the genus Gymnodinium. See Appendix 1.