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: Pavlova pinguis Green 1967; emend. Green 1980
Compiled data
Original Description
Size:
Extra details from original publication
There are two unequal flagella arising laterally towards the apical pole. The longer flagellum is 1½-2 times the length of the cell and it beats with a characteristic rapid, convoluted wave motion illustrated in Figure 1. In P. gyrans (Fig. 2) the action is such that the long flagellum has a looped appearance. In both species the long flagellum carries very fine hairs which are difficult to demonstrate satisfactorily but which may be just seen in the electron micrographs (Figs. 6 and 7). The shorter flagellum appears much finer under the light microscope and electron microscope observation shows that it is hairless with a more attenuated tip than the longer flagellum. It is directed stiffly outwards and beats with a relatively slow up and down motion. A third filiform organelle arises close to the flagella. This is an attaching organ similar, in this respect, to the haptonema found in members of the Haptophyceae (sensu Christensen, 1962). It is a very fine threadlike structure which can easily be overlooked since, as it only occasionally exceeds cell length when fully extended, the body frequently covers it. A similar organelle was observed in P. gyrans by Parke & Manton (in Bourrelly, 1957) but in this case, although fine, it is more conspicuous since its length may be at least three times that of the cell and it frequently trails behind when the organism is swimming (Fig. 2). In both P. gyrans and P. pinguis the attaching organ was observed to retract by contraction and not by coiling, the characteristic method of a haptonema. This observation implies a difference in structure between a haptonema and the attaching organ of Pavlova (Parke, 1961) and thus the latter should not be termed a haptonema. It is proposed therefore to call it a haptothrix (Gr. apto- attach, thrix a hair).
The remaining organelles of P. pinguis are similar to those of P. gyrans. There are two yellow-green laterally inserted chromatophores and a red stigma, the position of which varies between lateral and subapical. No contractile vacuole was detected. At the posterior end of the cell lie two bright refractive bodies which in the type species Butcher referred to as leucosin. They do not, however, give the typical leucosin reaction with cresyl blue and therefore appear to be of a different composition to the reserve material normally found in the Chrysophyceae. The nature of these bodies is under investigation. The nucleus, a varied number of small lipid bodies and peripheral muciferous organelles can also be observed.
The swimming action of P. pinguis is varied. It may swim rapidly in one direction, revolving slowly on its long axis. Sometimes it is rather more erratic, darting to and fro. After a short time under a cover slip the cells settle and may then vibrate rapidly. Eventually, as the cell begins to flatten, pseudopodium-like structures may be put out, but this does not take place as readily as in P. gyrans which quickly reacts to irritation by the formation of pseudopodia and the discharge of muciferous bodies.
Asexual reproduction in P. pinguis takes place by cell division in either the motile or non-motile phase (Figs. 3 and 4); the cells readily enter the latter phase, clustering together in a mucilaginous mass and losing their appendages (Fig. 5).
Asexual reproduction has also been recorded in the motile phase for P. gyrans.
Green, J. C. (1967). A new species of Pavlova from Madeira. British Phycological Bulletin. 3: 299-303. gs References:
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Pavlova pinguis: Catalog entry compiled by Jeremy Young. Viewed: 17-2-2025
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