Opisthokont

The opisthokonts (Greek: ὀπίσθιος (opísthios) = "rear, posterior" + κοντός (kontós) = "pole" i.e. "flagellum") are a broad group of eukaryotes, including both the animal and fungus kingdoms, together with the eukaryotic microorganisms that are sometimes grouped in the paraphyletic phylum Choanozoa (conventionally assigned to the protist 'kingdom'). The opisthokonts, sometimes referred to as the 'Fungi/Metazoa group', are generally recognized as a monophyletic clade.

Flagella

One common characteristic of opisthokonts is that flagellate cells, such as the sperm of most animals and the spores of the chytrid fungi, propel themselves with a single posterior flagellum. It is this feature that gives the group its name. In contrast, flagellate cells in other eukaryote groups propel themselves with one or more anterior flagella (see Zoospore morphological types). In some opisthokont groups, including most of the fungi, flagellate cells have been lost.

History

The close relationship between animals and fungi was suggested by Thomas Cavalier-Smith in 1987, who used the informal name opisthokonta (the formal name has been used for the chytrids by Copeland in 1956), and was supported by later genetic studies.