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Dinogymnium decorum
From Fensome et al., 2019:
Dinogymnium decorum (Deflandre, 1943, p.503–504, pl.17, fig.2; text-figs.8–9) Evitt et al., 1967, p.18. Holotype: Deflandre,
1943, pl.17, fig.2; text-figs.8–9. Originally Gymnodinium (Appendix B), subsequently (and now) Dinogymnium.
Age: Senonian.
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Original description, Deflandre 1943: Gymnodinium decorum. N. sp. (Fig. 8, 9 et Pl. XVII, fig. 2)
Holotype : AR 45. Silex ( ? Sénonien) S. 156, Vanves (Seine)
At first glance, this new species is reminiscent of Gymnodinium heterocostatum Defl., of which I depicted a lateral view in 1935. I give here a drawing of the specimen that I reported in 1936 (2, p.18) in a Senonian (Santonian) flint from the Micraster coranguinum chalk of Beynes. This is a specimen that also appears in lateral view (fig. 10), but which is more compressed than the type. It thus comes closer to Gymnodinium decorum, whose only holotype has the same orientation. However, it is easy to differentiate the two species. G. decorum, as it appears laterally, shows an epitheca and a hypotheca that are roughly equal, separated by a fairly wide transverse furrow, clearly less deep than that of G. heterocostatum. The general outline is long ellipsoidal, with rounded poles, the apex being slightly lowered. The membrane bears clear longitudinal ribs, which are generally impossible to follow to the poles. The observed dimensions are as follows: length 40 µm; width in lateral view, 17 to 18 µm. The width in frontal view, must greatly exceed 20 µm. The size is therefore clearly smaller than that of G. heterocostatum, which measures 60 to 65 µm in length. The absence of data on the frontal view does not allow It is hardly possible to compare G. decorum with the current species, in which, to my knowledge, there is no striated form with such a well-developed transverse groove.
Dinogymnium decorum (Deflandre, 1943, p.503–504, pl.17, fig.2; text-figs.8–9) Evitt et al., 1967, p.18. Holotype: Deflandre,
1943, pl.17, fig.2; text-figs.8–9. Originally Gymnodinium (Appendix B), subsequently (and now) Dinogymnium.
Age: Senonian.
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Original description, Deflandre 1943: Gymnodinium decorum. N. sp. (Fig. 8, 9 et Pl. XVII, fig. 2)
Holotype : AR 45. Silex ( ? Sénonien) S. 156, Vanves (Seine)
At first glance, this new species is reminiscent of Gymnodinium heterocostatum Defl., of which I depicted a lateral view in 1935. I give here a drawing of the specimen that I reported in 1936 (2, p.18) in a Senonian (Santonian) flint from the Micraster coranguinum chalk of Beynes. This is a specimen that also appears in lateral view (fig. 10), but which is more compressed than the type. It thus comes closer to Gymnodinium decorum, whose only holotype has the same orientation. However, it is easy to differentiate the two species. G. decorum, as it appears laterally, shows an epitheca and a hypotheca that are roughly equal, separated by a fairly wide transverse furrow, clearly less deep than that of G. heterocostatum. The general outline is long ellipsoidal, with rounded poles, the apex being slightly lowered. The membrane bears clear longitudinal ribs, which are generally impossible to follow to the poles. The observed dimensions are as follows: length 40 µm; width in lateral view, 17 to 18 µm. The width in frontal view, must greatly exceed 20 µm. The size is therefore clearly smaller than that of G. heterocostatum, which measures 60 to 65 µm in length. The absence of data on the frontal view does not allow It is hardly possible to compare G. decorum with the current species, in which, to my knowledge, there is no striated form with such a well-developed transverse groove.