Original descriptions of taxa. For coccolithophores, and many calcispheres, these are pages from the Farinacci & Howe Catalog of Calcareous Nannofossils. In other cases (e.g. non-calcifying haptophytes) the data is directly compiled on this site. The "Catalogue of Calcareous Nannofossils" was originally compiled by Prof A. Farinacci 1969-1989, since 2000 it has been updated and extended by Richard Howe - see The Farinacci and Howe Catalog - an Introduction.
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Current identification/main database link: Chrysochromulina cyathophora Thomsen 1979
Compiled data
Original Description
Size:
Extra details from original publication
Fig. 3 D shows the only complete cell observed. Two smooth flagella, 10-12 µm long, and a somewhat shorter coiling haptonema (c. 7 µm long when extended) arise close together from an almost spherical protoplast (c. 3 µm in diameter). lt should be remembered that cell measurements based upon whole mounts of cells are almost certainly underestimates (in particular cell diameter).
A closer inspection of e.g. Fig. 4 A shows that the cell is covered by scales of two types. The outer cylindrical scales are so numerous and firmly linked together that the inner circular scales are only rarely visible (Fig. 4C). Once recognized, however, the scale-case formed by the imbricated plate-scales can be identified from almost any micrograph. This armour of plate-scales appears as a clearly delimited area (cf. Figs. 3 A, 4A, arrowheads). The conspicuous size difference between the protoplast proper, which appears dark in Fig. 4 A, and the platescale casing (Fig. 4 A, arrowheads) is a rough estimate of the protoplast size reduction caused by the preparation technique.
The thin-walled cylindrical outer scales are nearly straight-sided. The diameter of the apparently completely collapsed anterior end is 0.20- 0.25 µm, whereas the base-plate - mostly appearing rectangular when dried down on the grid surface- has a diameter ranging from 0.16 µm to 0.19 µm. The wall thickness changes abruptly above the middle of the cylinder (Figs. 3B, E, 4C). The proximal surface of the base-plate shows a rather indistinct peripheral pattern of coarse radiating ridges (Figs. 3A, 4A, arrows). Attempts have been made to count the number of cylinder scales scattered around the C. cyathophora protoplasts. In each case the number was approximately 125. This is certainly an underestimate, the total number probably being more than twice this figure.
Direct evidence that the C. cyathophora scales are true cylinders cannot be drawn from whole mounts alone. However, the striking similarity - when comparison is based upon whole mounts- between the outer scales of C. cyathophora and the cylinder scales of C. microcylindra Leadbeater and C. megacylindra Leadbeater (both examined by thin sectioning of embedded material, see Leadbeater 1972 and Manton 1972 a), strongly speaks in favour of the assumption that the outer scales of C. cyathophora are also true cylinders.
The inner scale layer consists of circular, plate-like scales, approximately 0.8 µm in diameter (0.78-0.83 µm). Due to the relatively weak tendency of the periplast to fracture, only the distal surface of these scales are known. A very delicate arrangement of concentric ridges with a periodicity of c. 10 nm covers the whole plate.
Thomsen, H. A. (1979). Chrysochromulina cyathophora (Prymnesiophyceae), a new species from Danish coastal waters. Botaniska Notiser. 132: 71-76. gsReferences:
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Chrysochromulina cyathophora: Catalog entry compiled by Jeremy Young. Viewed: 17-2-2025
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