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Naiadinium polonicum (Woloszynska) Carty 2014

Previous name used: Peridiniopsis polonicum (Woloszynska) Bourrelly 1968; Glenodinium Gymnodinium Penard 1891

Phylum
Dinoflagellata
Class
Dinophyceae
Order
Thoracosphaerales
Habitat
plankton, littoral
Distinctive features
convex-concave shape, seen when it circles around itself while swimming
Organization
flagellated single cells
Color
yellow to golden-brown
Cell shape
a prolate spheroid that was punched in its “belly” so that from dorsal view it is concave
Cell diameter (D)
29-36 µm, median: 32 µm (N=32)
Cell length (L)
32-42 µm, median: 38 µm (N=32)
Cell biovolume
7,000-14,000 µm³, median: 10,000 µm³
Biovolume equation
V, µm³ = ((4/3)π L (D/2)²)/2 (half the volume of a prolate sphaeroid)

Morphological features

A medium-sized thecate dinoflagellate. The flagellated cells are oval, with the ventral side pressed in towards the other side as if it received a punch. As a result, the cell perimeter is convex when viewed from one side but concave when viewed from another (Plate 1). This concave/convex form is easily seen on a live, swimming cell: as it turns about its longitudinal axis its profile changes dramatically (Plate 1e). This feature is the most obvious for identifying this species. An additional diagnostic feature is the smooth and rounded cell shape (Plate 1). The epitheca is helmet-shaped and pointed and is approximately the same size as the broadly rounded hypotheca. The chloroplasts are small and discoid or ribbon shaped. A stigma (eyespot) may be present. Resting cysts are spherical with their thick cell wall covered by dense hairlike projections (not shown).
Naiadinium polonicum (Woloszynska) Carty 2014 — plate 1 (from source)
Plate 1. Naidinium (previously Peridiniopsis) polonicum. Light (a) and SEM (b, c) photographs, showing the general shape, cingulum and thecal plates. (a, b) ventral view; (c) dorsal view. (d-f): hand drawings showing the cells with their longitudinal flagellum, helmet-shaped epi-theca, round-based hypotheca, eyespot (stigma) and nucleus. The short and wide sulcus reaches the antapex (f). When viewed from the side (e) the convex-concave shape is evident. Light microscope photos: Alla Alster. SEM photos: Barbara Hickel. Hand drawings: from Popovsky and Pfeister 1990, after Penard 1891.

Ecology

Naiadinium polonicum occurs in the Kinneret plankton but in low numbers, usually < 5 cells/mL⁻¹ (Fig. 1). It is more abundant in shore samples than in pelagic waters. Its peak abundance is in April; it is absent in the water column during summer-fall (Fig. 2).

Environmental conditions

Higher abundance of N. polonicum is associated with the full range of Alkalinity, Ca, dissolved oxygen (not shown) and water temperatures, low concentrations of DIN (nitrate, ammonium) but intermediate concentrations of DON (Fig. 3). It tends to be more abundant at the lower salinities experienced in Lake Kinneret (Chloride < 250 mg/L) and at pH levels > 8.4 (Fig. 3).

Additional figures

Figure 1. Time series of Naiadinium polonicum cell abundance (mean epilimnion concentration) in Lake Kinneret, 1997-2020.
Figure 2. The seasonal pattern of Naiadinium polonicum cell abundance. Based on data for 1970-2020.
Figure 3. Naiadinium polonicum vs. selected environmental parameters from Lake Kinneret. Based on data for 1970-2020.

Cite this record as: Tamar Zohary, Alla Alster. 7 May 2026. Electronic publication. Israel Oceanographic & Limnological Research. https://kinneret-algae-atlas.org/ Searched on —.

Further reading

  1. Hansen G, Flaim G. 2007. Dinoflagellates of the Trentino Province, Italy. J Limnol. 66:107-141.
  2. Penard E. 1891. Les Peridiniacees du Lac Leman. Bull. Trav. Soc. Bot. Geneve 6: 1-63.
  3. Pollingher U, Hickel B. 1991. Dinoflagellate associations in a subtropical lake (Lake Kinneret, Israel). Arch. Hydrobiol. 120: 267-285.
  4. Popovsky, J. & Pfiester, L.A. 1990. Süßwasserflora von Mitteleuropa. Dinophyceae (Dinoflagellida). Vol. 6 pp. 1-272. Jena & Stuttgart: Gustav Fischer.

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