Main Content

The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 3716

J.M. Pincemin, P. Gayol, and P. Salvano; Observations on the Thecate Stage of the Dinoflagellate Pyrocystis cf. fusiformis (clones NOB2 and 111): Variations in Morphology and Tabulation. Arch.Protistenk 124:271-282, 1981

Reprint

In File

Notes

Pyrocystis cf. fusiformis clones NOB2/111 (Pincemin and Gayol 1978) has the following tabulation: P, 4', Oa, 7-8'', 6c, 7''', 1p, 1'''', but other possible interpretations are discussed. The apical closing platelets, whether they are porulated or not, are distinctive. The platelet, when it bears a pore, seems to impact a print on the antapical plate 1'''' of the anteriormost individual of a chain. One can observe seven or eight precingular plates of which two are very small. The postcingular plates 1''' and 7''' are narrow and well separated from the deep sulcus. Numerous variations can be observed in the shape of the plates, and particularly involving the "sensitive" plates 4'' or 5'' and 4'''. The plate formula of the P. fusiformis of Kofoid and Michener (Taylor 1972) is very similar to this one; however, some discrepancies are noted between the drawings of these authors and ours and the very different size of the cyst does not allow us to affirm that the two organisms are the same species. Our flagellate tabulation is also similar to that of P. acuta (Swift and Wall 1972) but is far from that of the P. fusiformis of Meunier and Swift (1977). The tabulation of P. cf. fusiformis clones NOB2/111 is of a gonyaulacoid type, more precisely near the genus Protogonyaulax (Taylor 1979) of the genus Gessnerium, after its reinterpretation by Loeblich III A.R., and Loeblich, L.A. (1979).