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Vannella mira Type strain (neotype) CCAP 1589/15.

Olympus CK2, Phase contrast
Locomotive forms, nucleus.

Vannella mira Type strain (neotype) CCAP 1589/15.

Olympus CK2, Phase contrast
Floating forms.

Photo: A.Smirnov

Basic references for identification:

  • Smirnov AV (2002) Re-description of Vannella mira (Gymnamoebia, Vannellidae) - an often mentioned but poorly known amoeba species. Protistology 2: 178-185
    Vannella mira (Schaeffer 1926) Smirnov 2002 CCAP 1589/15 (type strain - neotype)

  • Fan-shaped or semicircular vannella with pronounced "tail" in some cells. Frontal hyaloplasm consisted up to half of the body, usually it formes an anterior hyaline crescent. In few specimens there are small dorso-lateral ridges or small lobes at the frontal hyaloplasm. Length of the locomotive form on the plastic base of the Petri dish 15-35 mkm (average 28.5 mkm); breadth 15-35 mkm (average 26.5 mkm). Length/Breadth ratio 0.5 - 1.8.

  • Floating form variable. It may look as:
    1. Radial floating form with 3-11 radiating pseudopodia; some pseudopodia may furcate. During the development of the floating form pseudopodia elongate, but sometimes the development may "freeze" and floating amoeba for a long time has short, curved, relatively thick pseudopodia.
    2. Floating form with all cytoplasm in the conical basal thickenings of 3-4 pseudopodia (in this case the basement of pseudopodia consists of the granuloplasm).
    3. Floating form with 7-11 pseudopodia, producing the impression of a cell rotating, with pseudopodia lagging behind.
  • Uninucleate, vesicular nucleus about 6 mm in diameter. Single, central, optically homogenous nucleolus about 3 mm in diameter (when measured in live specimens). No crystals in the cytoplasm. One or two large, distinctive vacuoles that do not contract normally present. No cysts observed.

  • Cell coat consisting of glycostyles, about 130 nm in length without accociated simple filaments.

  • Marine, lives under the salinity range 6-90ppt (special tests not performed). Feeds on bacteria, diatoms, algae and filamentous cyanobacteria. Observed habitat: cyanobacterial mats in Camarque, France, salinity 70-80 ppt.

  • Identification of a species may be difficult. The story of "Vannella mira" is vary knotty, descriptions of different authors sometimes are in evident disagreement. Not less that three different vannellians were named as "Vannella mira" in different periods. Most remarcable detail is the organisation of the floating form. Please consult the reccomended paper for detailed historical and taxonomic account on this species.

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