INVERTEBRATE ZOOLOGY - H. I. Shcherbak - 2008

PROTISTS - PROTISTA

PROTOZOA

FLAGELLATES

PHYLUM CHOANOFLAGELLATES (CHOANOMONADA)

Very small (3-25 µm) free-living, solitary, or colonial flagellates widely distributed in fresh and marine waters worldwide. Both planktonic and sessile forms occur among them. Planktonic choanoflagellate colonies are spherical, whereas sessile ones form treelike branched colonies (Fig. 4). Many choanoflagellates possess loricae composed of Cellulose or rigid siliceous strips or fibers. Species lacking a lorica are surrounded by mucus or a thin organic pellicle.

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Fig. 4. Colonies of collar flagellates (after Zhukov, Karpov): a - spherical Sphaeroeca volvoxr, b - treelike Codonosiga botrytis

Choanoflagellates are characterized by the presence of a single flagellum surrounded by a collar of microvilli. A central filament is located in the transition zone of the flagellum; microtubular roots diverge radially from the flagellar kinetosome. Cell/35.html">Mitochondria contain lamellar cristae. The Nucleus is single. The phylum includes a single class.



Last update: 13/08/2026

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