Nannotax3 - ntax_Farinacci - Nephrochloris salina

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: Nephrochloris salina Carter 1937

Current citation: Rebecca salina (Carter 1937) Green in Edvardsen et al. 2000

Cellula parva, nuda, elliptica, latitudine paulo longiore, forte compressa, dorsiventrali, duobus flagellis, altero circa 1/3 cellulae longitudinis, altero 1/2—2 plo longiore, utroque in depressione parva sub apicem in latere ventrali inserto; a latere visa anguste ovata, parva depressione subapicali in latere ventrali praedita ubi flagella inserta sunt; a vertice visa elliptica; 2 chromatophoris, luteoviridibus, parietalibus et lateralibus, latus ventrale fere tegentibus, sed non nisi supra minimam partem lateris dorsalis extendentibus; plerumque cum 2 granulis refringentibus conspicuis et caeruleis, saepe forma irregularibus et interdum aut uno aut pluribus globulis magnis refringentibus. Desunt stigma et vacuola contractilia.

Cell small, naked, elliptical, slightly longer in width, perhaps compressed, dorsiventrally, with two flagella, one about 1/3 of the cell length, the other 1/2-2 times longer, both inserted in a small depression under the apex on the ventral side; seen from the side narrowly ovate, provided with a small subapical depression on the ventral side where the flagella are inserted; seen from the top elliptical; 2 chromatophores, luteo-green, parietal and lateral, almost covering the ventral side, but only extending over a small part of the dorsal side; usually with 2 conspicuous and blue refracting granules, often irregular in shape and sometimes with one or more large refracting globules. Stigma and contractile vacuole are absent.

Approximate dimensions 5-7 x 3-5 x 2-3 µm

This small organism was not infrequent and was often to be found in the surface films of various samples which had been standing undisturbed for some time. Its small flattened body seems to have a firm periplast, but no membrane, and its form is very characteristic, particularly when at rest, when the long flagellum lies gracefully coiled in an S shape, either motionless, or with a gentle wave passing along it (PL 2 Fig. 10). The second flagellum is very delicate, and not at all easy to see in side view, however, its presence is unmistakable (PI. 2 Fig. 13). In the front view it can frequently be seen that there are two dots near the apex which represent the points of origin of the two flagella, even if the tiny second flagellum cannot be detected. When the organism is in motion it can move along either with the flat body constantly in one plane, or it can rotate.

There are two yellowish green chromatophores, one fitting closely to each lateral margin; they extend well over the ventral face, but only slightly over the dorsal face (PI. 2 Figs. 10, 12, 13). Two bluish refractive granules can usually be seen in the middle of the cell (PI. 2 Figs. 10, 13, gr). These granules are rather irregular in outline and are probably of the nature of food reserves, as either one or both may be absent and there is considerable variation in size and shape. In stained preparations mounted in balsam they frequently appear to lie each in a separate vacuole (PL 2 Figs. 20, 21). The nucleus of the cell is not easy to locate, but in the specimen figured on PL 2 Fig. 21, it appeared to be towards the base of the body. One or two large refractive lumps of leucosin may further be included in the cell contents (PL 2 Figs. 15—19,1).

The organism is not at all metabolic as a general rule, but on rare occasions the periplast may become plastic so that the cell becomes slightly amoeboid and loses its characteristic shape (PL 2 Figs. 15—17). At times the organisms may lose their flagella and enter into a palmelloid condition forming a stratum with other associated organisms such as Euglena spp. (PL 2 Figs. 17, 22).

Division occurs by longitudinal fission in either the motile or the resting condition. The plastids seem to divide transversely before cell division is complete (PL 2 Fig. 19). The individuals may remain in close proximity after division (PL 2 Fig. 11).

This organism does not agree exactly with any other alga previously described. There is some similarity to Ankylonoton pyreniger Pascher (1932 B, p. 305), but this is a much bigger organism which has a single dorsal plastid and a large pyrenoid, and it is not as flattened as my form. Heterochloris mutabilis Pascher (1914, p. 159) and Chlorochromonas minuta Lewis (1913, p. 254) are not sufficiently flattened to come into consideration.

Pascher (1930, p. 403) has described another heterokonten flagellate as Chlorokardion pleurochloron in which the body is slightly dorsiventral and is provided with the typical long and short flagella of this group. This organism is, however, much larger than my form, possesses 2—4 plastids and is characterised by the slightly asymmetrical shape of its front view, a feature which is not constant or conspicuous in my alga. Finally there is a rather striking resemblance to Nephrochloris incerta Geitler and Gemisi (Geitler , 1925 B, p. 604), which is about the same size. This differs, however in being less flattened and it has only one plastid and one flagellum; but the authors comment on the frequent difficulty of detecting the second small flagellum in these algae. The position of the plastid is also different as it lies on the dorsal surface in N. incerta, whilst in the Bembridge alga the plastids cover more of the ventral surface than the dorsal.

It is very difficult to decide whether my organism is nearer to Nephrochloris Geitler and Gemisi or to Chlorokardion Pascher, but in many ways the similarity to Nephrochloris incerta is more attractive, in spite of the the single plastid and the solitary flagellum of the latter. With reference to this last point it should be kept in mind that the second smaller flagellum may possibly have been overlooked by Geitler and Gemisi, as indeed it was overlooked in the present organism for a considerable time. If this is so, the two forms only differ in minor points, e. g., slight differences in the form of the cell, in the number and position of the plastids, and in the absence of a contractile vacuole in N salina.

Was placed in Pavlova, now in Rebecca

References:

Carter, N. (1937). New or interesting algae from brackish waters. Archiv für Protistenkunde. 90: 1-68. gs

CATALOG - Nephrochloris salina

References:

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