Main Content
< Top page

The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Stylodinium

Stylodinium Klebs (ref. ID; 3726)

[ref. ID; 3726]
Starmach (1974) correctly included the genus Dinopodiella Pascher to show the main diacritical features between both genera. His detailed description of the genus Stylodinium Klebs (incl. Dinopodiella Pascher) is as follows: "cell globose to ovoid, attached to water plants by means of a stalk varying in length. Cellulose cell membrane thick, without structure. The protoplast without visible furrows and eyespot. The chromatophores small, yellowish. The nucleus is with characteristic structure of the class. In the protoplasma are present reddish brown globules. The stalk is created from firm cellulose with a center indissoluble, in concentrated sulphuric acid. Between cell body and stalk a nipple is present (except S. cerasiforme!). Multiplication by means of gymnodinium-like zoospores. Attached as epiphytes on algae and waterplants in freshwaters". (ref. ID; 3726)
  1. Stylodinium cerasiforme (ref. ID; 3726)
  2. Stylodinium globosum Klebs (ref. ID; 3726)
  3. Stylodinium sphaera Pascher (ref. ID; 3726)

Stylodinium sphaera Pascher (ref. ID; 3726)

Descriptions

We observed S. sphaera specimens attached to empty Oedogonium sp. cells. Their size ranged from 25.5 to 31.7 x 15.0 to 38.7 um excluding the stipe. Contrary to original description stalks were one-third to one-and a quarter times as long as the cell diameter. We also detected cells larger in diameter with longer stalks which resembled S. globosum Klebs, originally described from Java and giant cells maximally 60 um in diam. and 80 um stalk length. Cell color varied from bright green to brown to bright orange. All cells had one or more reddish-brown globules. We did not observe the eyespot, pyrenoid and furrows in vegetative stage. We studied the orange cells in detail with their quick plasma circulation. We saw many such orange cells rupture and liberate two orange, relatively quickly moving amoeboid stages leaving behind the reddish globules. We were able to determine these stages Vampyrella lateritia (Fresenius) though they were not in heliozoan form (after Kudo, 1971). These zoids possessed two flagella-like filopodia, 8 to 12 contractile vacuoles and many fine filopodia. The typical dinocaryon and chromatophores were not visible in the light microscope in this stage. Filopodia shortened within seconds as an amoeboid stage settled on an intact Oedogonium cell. Within seconds it punctured (probably enzymatically) the wall and swelled suddenly (10 to 15s) as it emptied the Oedogonium cell of it content. Several times an amoeboid stage preyed upon Oedogonium cells before developing the Stylodinium form with a stalk within 30 min. Within ten more min the protoplasma of some cells divided into four to eight small gymnodinoid-like zoospores similar to those described for Cystodinium phaseolus Pascher 1928. The typical dinocaryon was visible. We did not detect the true eyespot. Other amoeboid stages (Vampyrella lateritia) formed the Stylodinium shape within 10 to 15s after settling on intact Oedogonium cells. After a few seconds a large central vacuole was visible; the chromatophores and dinocaryon were invisible. Contractile vacuoles were not observed at that stage. After several min the Oedogonium cell was quickly (seconds) punctured enzymatically by means of one tentacle-stalk and emptied the cell content into its vacuole. The narrow canal in the centre of the tentacle-stalk was visible with the light microscope in every case. Sometimes the tentacle -stalk became hypertrophied. By means of this thick tentacle it pushed itself from an empty to a live Oedogonium cell. After emptying several Oedogonium cells the tentacle weakened and extend itself in seconds - Stylodinium cerasiforme Pascher. In about half an hour the cell content divided into two parts and two heliozoan stages were liberated. We were also to determine this stage as Actinophrys sol (Ehrenb.) with 8 to 12 contractile vacuoles, straight axopodia two to three times length of the cell. On some specimens we saw the discoidal, silicious spicules which normally extend outwards along the axopodia. Thus, it appears to be related to the genus Raphidiocystis Penard. Also, these zoids possess two flagella-like-filopodia, which are difficult to distinguish from the numerous axopodia. In the reddish cytoplasm the dinocaryon was invisible. Axopods shortened within seconds as a heliozoan stage (Actinophrys sol, Raphidiocystis sp.) settled on intact Oedogonium cell. Within seconds it punctured (enzymatically) the wall and swelled suddenly as it emptied the Oedogonium cell of its content. Several times a zoid preyed upon an Oedogonium filaments before developing the Stylodinium form with one tentacle-stalk - Stylodinium cerasiforme. Within several hours it developed into a motionless resistant stage with reddish globules above and a refractive sphere below. Once a heliozoan stage ceased preying, it changed into a typical Stylodinium cell with one tentacle-stalk within 30 min. Within ten more min the protoplasm of some cells divided into four larger gymnodinoid cells with eyespot, which may have been gametes, or turned orange and released amoeboid stages. Several pairs of the so-called gametes were seen dancing around each other. These gymnodinoid gametes had a definitive dinocaryon, two yellowish-brown chromatophores, stigma and one to two reddish spheres. The girdle twisted left, the sulcus reached to the antapex. One member of the pair was slightly larger (gymnodinium shaped) than the other (gyrodinium shaped). We suspect they were gametes as they "danced" around one other in manner similar to that of other dinoflagellate gametes. We never saw the fusion of these, presumably gametes. (ref. ID; 3726)