Acantharia

Jean Febvre, Oceanological Observatory, Villefranche‐sur‐Mer, France
Colette Febvre‐Chevalier, Oceanological Observatory, Villefranche‐sur‐Mer, France

Published online: May 2001

DOI: 10.1038/npg.els.0002102

Acantharia are marine planktonic protozoa related to Radiolaria. Their main distinctive features are the mineral skeletons of strontium sulfate, the radial cytoplasmic extensions known as axopods, the extracellular fibrillar network or periplasmic cortex and the contractile filament bundles known as myonemes.

Keywords: eukaryota; protozoa; actinopoda; radiozoa; celestite-based skeleton

Figure 1. A living acantharian. Bar, 25 m.
Figure 2. Structure of an acantharian showing the central spherical endoplasm, limited by the capsular wall, and the ectoplasm covered by the periplasmic cortex. The spicules, surrounded by a perispicular vacuole, radiate from the cell centre. Myonemes are linked proximally to the periplasmic cortex at the periphery of the cell and distally to the apex of the spicules. Thin radiating axopods project for a distance of several microns into the surrounding water. The cell membrane limits the endoplasm and the islets of ectoplasm; it surrounds the distal part of the spicules and the myonemes.
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 References
    Febvre-Chevalier C and Febvre J (1993) Structural and physiological basis of axopodial dynamics. Acta Protozoologica 32: 211–227.
    book Schewiakoff W (1926) "Die Acantharien des Golfes von Neapel. Fauna und Flora". In: Fauna und Flora des Golfes von Neapel. Rome: Friedlander.
 Further Reading
    book Cachon J and Cachon M (1985) "Superclass Actinopodea Calkins 1902. I. Class Acantharea Haeckel 1881". In: Lee JJ, Hutner SH and Bovee EC (eds) Illustrated Guide to the Protozoa, pp. 274–282. Lawrence, KS: Allen Press
    Corliss JO (1994) An interim utilitarian (‘user-friendly’) hierarchical classification and characterization of the protists. Acta Protozoologica 33: 1–51.
    Febvre J and Febvre-Chevalier C (1989a) Motility processes in the Acantharia. II. A  Ca2+-dependent system of contractile 2–4 nm filaments isolated from demembranated myonemes. Biology of the Cell 67: 243–249.
    Febvre J and Febvre-Chevalier C (1989b) Motility processes in the Acantharia (Protozoa). III. Calcium regulation of the contraction–relaxation cycles of in vivo myonemes. Biology of the Cell 67: 251–261.
    book Febvre J (1990) "Phylum Actinopoda, Class Acantharia". In: Margulis L, Corliss JO, Melkonian M and Chapman D (eds) Handbook of Protoctista, pp. 363–379. Boston: Jones and Bartlett
    Febvre-Chevalier C and Febvre J (1993) Structural and physiological basis of axopodial dynamics. Acta Protozoologica 32: 211–227.
    book Febvre J and Febvre-Chevalier C (1995) "Acantharien". Röttger R Biologie der Protozoen. Ein Praktikum zur Vielfalt der Formen und Lebensräume der Einzeller, pp. 120–125. Stuttgart: G. Fischer Verlag.
    Michaels AF (1988) Vertical distribution and abundance of Acantharia and their symbionts. Marine Biology 97: 559–569.
    Michaels AF (1991) Acantharian abundance and symbiont productivity at the VERTEX seasonal station. Journal of Plankton Research 13: 399–418.
    book Schewiakoff W (1926) "Die Acantharien des Golfes von Neapel. Fauna und Flora". In: Fauna und Flora des Golfes von Neapel. Rome: Friedlander.
    Zettler LA, Sogin ML and Caron DA (1997) Phylogenetic relationships between the Acantharea and the Polycystinea: a molecular perspective on Haeckel's Radiolaria. Proceedings of the National Academy of Sciences of the United States of America 94: 11411–11416.

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Article Title: Acantharia
 
How to Cite close
Febvre, Jean, and Febvre‐Chevalier, Colette(May 2001) Acantharia. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0002102]