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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Citation: Chrysochromulina acantha Leadbeater&Manton 1971Taxonomic rank: speciesType specimens: Type culture no. 326 in the Plymouth collection.Standardised type level: 160_HOLOCENEType locality: in the sea off Plymouth (England)Farinacci catalog page (& compiler): n/a Current citation: Chrysochromulina acantha Leadbeater and Manton 1971
Original Description Cells usually saddle shaped, convex dorsally, concave ventrally, c. 6-10 µm in length and breadth, with two parietal pale golden-brown plastids each with a non-projecting pyrenoid. Two equal flagella arising with the haptonema from the concave surface near the posterior end. The haptonema, containing 7 microtubules, c. 40 µm when fully extended (= twice the flagellar length) coiled into a helix of 15-20 gyres when retracted. Cells covered with mucilage and with two layers of very thin scales visible only with an electron microscope, the scales of the outer layer carrying spines, those of the under layer spineless and platelike. The latter, c. 0.5 µm wide x 0.6 µm long, with a pattern of sparse ridges ra- diating from the centre to a thickened margin, rims absent. The spiny scales similar in patterning but circular, e. 0.4-0.5 µm in diameter each carrying a single central spine, c. 0.5 µm long, supported by four decurrent struts reaching the plate margin peripherally but raised above it centrally. Mnciferous bodies numerous, scattered in the cytoplasm near the surface. Size: Cells 6-10 µm; under-layer scales 0.5 µm x 0.6 µm; outer-layer scales 0.4-0.5 µm with spine, c. 0.5 µm long Etymology: Latin, acantha, Greek, akantha -- a spine) Extra details from original publication The scales are of two types (Figs.7-13). The outermost scales carry spines, each spine supported by four struts attached to the upper surface of a subtending fiat base plate. The latter shows a sparse woven pattern dominated by delicate radiating ridges equally visible on both surfaces (Figs. 9 and 11). There are central and marginal tbiekenings but no obvious rim (Fig. 10). The struts supporting the spine reach the margin of the subtending plate (Fig. 11) but are arched above it centrally (Fig. 10). When seen in a tangential section, the struts are found to be arranged in two pairs joined by a horizontal bar (Fig. 11). The average diameter of the approximately circular base plates is 0.45 µm and the average length of spine is 0.5 µm.
Scales of the second type underlie the first when in position on the cell. They are oval flat plates, somewhat larger than the base-plates of spined scales but similar in patterning and construetion (Figs.9, 12 etc.). The sectional view is best seen in Fig. 13 in which a mature spineless scale has not yet been released from the Golgi system. The marginal thickening but otherwise thin texture is well shown. When seen in other views the absence of a rim makes the dorsal and ventral surfaces of such scales virtually indistinguishable (Fig. 12). The average dimensions are : 0.62 x 0.52 µm.
References:
Leadbeater, B. S. C. & Manton, I. (1971). Fine structure and light microscopy of a new species of Chrysochromulina (C. acantha). Archiv für Mikrobiologie. 78: 58-69. gs
Chrysochromulina acantha: Catalog entry compiled by Jeremy Young. Viewed: 17-2-2025