Nannotax3 - ntax_Farinacci - Chrysochromulina parkeae <title>Nannotax3 - ntax_Farinacci - Chrysochromulina parkeae

CATALOG - Chrysochromulina parkeae


Folder trail: ntax_Farinacci -> Haptophytes -> Chrysochromulina -> Chrysochromulina parkeae
Folders this level: << < C. kappa, C. lanceolata, C. latilepis, C. laurentiana, C. leadbeateri, C. limonia, C. mactra, C. mantoniae, C. megacylindra, C. microcylindra, C. minor, C. novae-zelandiae, C. orbiculata, C. pachycylindra, C. papillata, C. parkeae, C. parva, C. pelagica, C. planisquama, C. polylepis, C. pontica, C. pringsheimii, C. pseudolanceolata, C. pyramidosa, C. quadrikonta, C. rotalis, C. scutellum, C. simplex, C. strobilus, C. tenuispina, C. tenuisquama> >>

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: Braarudosphaera bigelowii (Gran & Braarud 1935) Deflandre, 1947

Compiled data

Citation: Chrysochromulina parkeae Green and Leadbeater 1972
Rank: Species
Type specimens: Holotype designated as fig 1, and so Plymouth Material
Standardised type level: 160_HOLOCENE
Farinacci catalog page (& compiler): n/a
Current citation: Braarudosphaera bigelowii (Gran & Braarud 1935) Deflandre, 1947


Original Description

Cells motile, elongate, ovate, 10-26 µm long, 5-10 µm wide, dorsoventrally compressed. Two fiagella and one haptonema arising close together at one end; fiagella equal, smooth, homodynamic, 8-20 µm long; haptonema shorter than fiagella 2.5-4.5 µm long. Plastids two, golden-brown, lateroparietal.
Scaly investiture present, visible with light microscope. Scales of four forms;

Size:
Cells 10-26 µm long spines 20-30 µm long; scales 1-5 µm long

Etymology:
To acknowledge the great contribution made by Dr Mary Parke to the study of marine phytoplankton

Extra details from original publication
Marine. Recorded from Norway (Herdlafjorden, station H 180-70, and Hjeltefjorden, station H 178-70) on 8 August 1970; from positions 50 02' N, 04 22' W and 50 17' N, 04 26½' W in the English Channel on 12 and 13 August 1970.

Observations on living material: Only cells from the Plymouth samples were seen in any detail in the living condition. They were immediately striking in appearance because of their large size, and particularly because of the conspicuous group of spines commonly situated posteriorly (PI. IIIE, F; Text-Fig. 1 A). The dimensions of the cells and their appendages in the Plymouth samples were approximately two to three times greater than those from Norway, being 17-26 µm long by 6-10 µm wide, in contrast to the latter which were 10-15 µm long by 5-7 µm wide. The most obvious contents were the two golden-brown plastids which extended the length of the cell, together with numerous refractive droplets.

The two flagella, 8-20 µm long (half to equal cell length), were located together with the haptonema (2.5-4.5 µm long) at the anterior end during swimming. When in motion the cell revolved slowly about its longitudinal axis and it was then possible to detect that it was somewhat compressed. The haptonema was directed forwards, and although it was observed to be flexible and to bend slightly, it was not observed to coil or to attach to either the slide or cover-slip.

The investment of plate and spine scales could be seen clearly with anoptral or phase- contrast microscopy (PI. IIIE-G). The spines were normally located at the posterior end of the cell, but individuals with spines at both ends were also recorded (PI. IIIG ; Text-fig. IB). The spines occurred in groups of 3-6 (although the number varied owing to the ease with which they were shed under observational conditions) and usually diverged outwards from their point of attachment to the cell.

Observation with the electron microscope: The general features of the cell and scaly covering are illustrated in Plate I. Two types of scale can be recognized, namely spines and elliptic plate scales. Of the latter the largest possess rims, the medium-sized lack rims and the smallest are relatively narrow and carry a wide' border '.Their exact arrangement cannot be deduced from whole mounts but it is evident from Plate IIIF (upper arrow) that the largest plates are situated outermost. Although there is an approximately twofold difference in size between the scales of the Plymouth and Norwegian populations (Table 1) it is convenient to discuss their morpho- logical features together drawing attention to the differences as they arise.

The rimmed plate scales (Pis. I, arrows; II A, B ; IV A, E, F) are the largest so far recorded in the genus Chrysochromulina (see Table 1). The proximal surface is distinguished by a complicated pattern of ridges some of which appear to be straight and others curved and whose arrangement is best understood by reference to Plate IVE. The distal surface dis- plays irregularly disposed fibrils surrounded by a raised flap arising slightly submarginally (PI. IVF) and sometimes showing a series of short vertical bars near the base (Pis. II A, B; IVA, E).

The medium-sized plate scales (Pis. I; IIA, C; PI. IVA, D) are the most abundant and show the greatest variation in size (Table 1) and shape; they may be markedly elliptic (length twice the breadth) or almost circular. The patterns on the two surfaces resemble those on the largest plate scales except that the distal surface possesses a peripheral band of thickened fibrils, relatively narrow (about one-tenth of the total scale width) in the Plymouth specimens (PI. IIA, C) and considerably wider (approximately one quarter of the total scale width) in the Norwegian material (PI. IVA, D). All show a fairly regular row of pits and ridges at the outer edge (Pls. II E ; IVD).

The smallest plate scales (Pls. I; IIA, B; IVB, C) are narrowly elliptic in shape and are usually associated with the spines. They possess the familiar radiating pattern of ridges on their proximal surface but the central region of irregular fibrils on the distal surface is surrounded by a wide peripheral 'border' with coarse cross-striations (see especially Plate IVB). These scales are quite distinct (as seen in PI. I) and on some Norwegian specimens were observed at both poles of the cell.

The long spines (Pls. I; II A; III) taper gradually to fine distal points (PL Ill A) and have 'spoon-shaped' bases (PI. Ill A, B, C) which can be seen with anoptral or phase-contrast microscopy (PI. III F , lower arrow, G). The bases show certain details resembling those of the plate scales, one surface bearing an arrangement of radiating ridges and the other an irregular array of fibrils (Pl. III B , C). Both margins appear to be infolded or inrolled (although this is more strongly developed on one side than the other) and appear to be continuous with the shaft. The latter is regularly cross-striated along its length, as well demonstrated in Plate III D , the periodicity of the cross-banding in this particular group of spines being 0-07µm. In all samples, the periodicity is comparable with that of the vertical bars or coarse marginal striations found on the other scale forms (see especially Plate II A).

Discussion: The presence of two smooth flagella, a haptonema and apparently unmineralized scales of more than one type are sufficient reason for placing this species, at least provisionally, within the genus Chrysochromulina. The only possible alternative at present known to us might be the newly described genus Chrysocampanula Fournier (1971), in which the haptonema is reported not to coil, a detail shared with the present species. However, whether this is a valid generic criterion must remain uncertain until some fine-structural information on Chrysocampanula is available, and therefore, on existing information, we have no choice but to treat our new species as a Chrysochromulina.

On the other hand, the characteristic morphology of the scales of C. parkeae, especially that of the spines, clearly separates it from any other named species of this genus. When viewed by light-microscopy the species shows a superficial similarity to C. pringsheimii (Parke & Manton, 1962); but careful examination with anoptral or phase-contrast microscopy is sufficient to resolve differences between the two species, and these are confirmed by the electron-microscopy of shadowcast whole mounts.

Certain features of the patterning (e.g. the radiating and crescentic ridges on the proximal surface and the regular array of fibrils on the distal surface) are common to all the plate scales encountered in this species. It is interesting to note the similarity of this patterning to that found on the surfaces of the spoon-shaped bases of the spines, but the significance of this comparison must await the availability of detailed fine structural analysis of sectioned material.

The range of size and morphology encountered in this study highlights the importance of examining, whenever possible, natural populations as well as unialgal isolates, when identifying and diagnosing species of nanoplankton. From this work and others (e.g. Leadbeater, 1972) it appears that there is more variation in nature than could be anticipated from observations on cultures, and thus the extension of electron-microscope techniques and observations to wild material is becoming increasingly important.

Editors' Notes
Now known to be an alternate life-cycle phase of Braarudosphaera bigelowii

References:

Green, J. C. & Leadbeater, B. S. C. (1972). Chrysochromulina parkeae sp. nov. [Haptophyceae] a new species recorded from S.W. England and Norway. Journal of the Marine Biological Association of the United Kingdom. 52: 469-474. gs


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Chrysochromulina parkeae: Catalog entry compiled by Jeremy Young. Viewed: 6-2-2023

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