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Chaos nobile CCAP 1511/2.

Olympus BH2, DIC
Polytactic and orthotactic locomotive forms,
uroidal structures and nuclei.

Photo: A.Smirnov

Chaos nobile (Penard, 1902) Bovee & Jahn, 1973
CCAP 1511/2

  • Lentgh in locomotion 240-820 mkm (average 450-500 mkm). Majority of amoebae orthotactic in locomotion (monopodial with distinct lateral wrinkles), few are polytactic (polypodial). Crystals are small bipyramids. This species has very characteristic floating form of irregular outlines, with branching and re-branching pseudopodia. Each pseudopod possess a pronounced thickening at the distal end.

  • 6-49 discoid, biconvex nuclei of granular type, 15-23 mkm in diameter (average 18.5 mkm).

  • Surface coat consists of crinkled filaments, about 200 mkm in length, radiating from amorphous basal layer. Overall thickness of the cell coat 176-240 nm. Honeycomb-like nuclear lamina (Page, 1986).

  • This species resembles Chaos glabrum very much. The major LM difference is the floating form. Chaos nobile has a very specific floating form with branching and re-branching pseudopodia, bearing a characteristic thickenings at the proximal ends (see Page, 1988). In Chaos glabrum the floating form is radial, like in Amoeba proteus. Another difference is the ultrastructure of the cell coat. TEM of the cell coat is obligate for identification, keep in mind that filaments in proteus-like amoebae may coagulate under the EM fixation.

  • The culture is available from the from the Culture Collection of Algae and Protozoa, CEH Windermere, UK)

  • Freshwater, Europe, North America.
    Cultivation: MP + Colpidium colpoda. May be maintained for some time in PJ + wheat (rise) grain, in presence of small ciliates and flagellates.

  • Basic references for identification

  • Page F.C. 1986. The genera and possible relationships of the family Amoebidae, with special attention to comparative ultrastructure. Protistologica. 22: 301-316.
  • Page F.C. 1988. A new key to freshwater and soil gymnamoebae. FBA, Ambleside. 122p.
  • Page F.C. 1991. Nackte Rhizopoda. in: Protozoenfauna, b.2. Gustav Fisher, Stuttgart. 3-172.
  • Smirnov A.V. and Goodkov A.V. 1997. Description of a large, multinucleate lobose amoeba Chaos glabrum n.sp. (Lobosea, Amoebidae), with notes on the diagnosis of the genus Chaos. Acta Protozool. 36: 227-233.

    Note that the keys by Page from 1988 and 1991 harbour slightly different sets of illustrations for this species.

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