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Circulodinium distinctum ssp. distinctum
From Fensome et al., 2019:
Circulodinium distinctum ssp. distinctum
Autonym. Holotype: Deflandre and Cookson, 1955, pl.2, fig.14. Now redundant. Originally Cyclonephelium distinctum subsp. distinctum, subsequently Circulodinium distinctum subsp. distinctum.
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Original description as Cyclonephelium distinctum: [Deflandre and Cookson, 1955, p. 285-286]:
Description:
Ornamentation typically consisting of numerous short, solid appendages of variable width, the apices of which are either bluntly pointed, capitate, enlarged, or forked; rarely the processes are joined to one another forming short lamellae. They are irregularly disposed, most numerous at the equator and becoming progressively fewer towards the poles, from which they are entirely absent. Surface of shell distinctly punctate.
Dimensions:
Diameter of shell, 64-97 µm, length of appendages 2.5-18 µm.
Affinities:
It is sometimes difficult to separate C. compactum from C. distinctum, surely two closely related species, but when a series of individuals is observed the distinction between them becomes clear. In a few examples of C. distinctum lamella-like appendages have been observed amongst the typical processes of this species, but so far isolated appendages similar to those of C. distinctum have not been seen in C. compactum.
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Cookson and Eisenack, 1974, p.74: Cyclonephelium distinctum var. distinctum:
Remarks:
As shown by us, in particular in our 1962 paper, the C. distinctum is a greatly varying species. This becomes again apparent, mainly in the Balcatta bore. An extreme form is the specimen figured in Figure 7. We do not consider it as appropriate to separate further variants on the basis of the more or less developed processes.The processes occasionally extend very far from the margin of the shell toward the middle. Since, on one and the same specimen, they can moreover greatly vary in form, a close relationship to the Heterosphaeridium heteracanthum (Defl. & Cooks. 1955) seems to be involved here.
Circulodinium distinctum ssp. distinctum
Autonym. Holotype: Deflandre and Cookson, 1955, pl.2, fig.14. Now redundant. Originally Cyclonephelium distinctum subsp. distinctum, subsequently Circulodinium distinctum subsp. distinctum.
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Original description as Cyclonephelium distinctum: [Deflandre and Cookson, 1955, p. 285-286]:
Description:
Ornamentation typically consisting of numerous short, solid appendages of variable width, the apices of which are either bluntly pointed, capitate, enlarged, or forked; rarely the processes are joined to one another forming short lamellae. They are irregularly disposed, most numerous at the equator and becoming progressively fewer towards the poles, from which they are entirely absent. Surface of shell distinctly punctate.
Dimensions:
Diameter of shell, 64-97 µm, length of appendages 2.5-18 µm.
Affinities:
It is sometimes difficult to separate C. compactum from C. distinctum, surely two closely related species, but when a series of individuals is observed the distinction between them becomes clear. In a few examples of C. distinctum lamella-like appendages have been observed amongst the typical processes of this species, but so far isolated appendages similar to those of C. distinctum have not been seen in C. compactum.
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Cookson and Eisenack, 1974, p.74: Cyclonephelium distinctum var. distinctum:
Remarks:
As shown by us, in particular in our 1962 paper, the C. distinctum is a greatly varying species. This becomes again apparent, mainly in the Balcatta bore. An extreme form is the specimen figured in Figure 7. We do not consider it as appropriate to separate further variants on the basis of the more or less developed processes.The processes occasionally extend very far from the margin of the shell toward the middle. Since, on one and the same specimen, they can moreover greatly vary in form, a close relationship to the Heterosphaeridium heteracanthum (Defl. & Cooks. 1955) seems to be involved here.