Note

Flagellates: Heterotrophic Protists With Flagella

David J. Patterson

The flagellates are a grade of organisation. Traditionally, they are those protozoa which spend most of their existence moving or feeding with a small number of flagella. This type of organization is the most widespread among protists. Of the 60 lineages of protists identified among the eukaryotes, 27 satisfy the condition of being a protozoan flagellate. In addition, alveolates and stramenopiles include heterotrophic flagellates, as do several groups often thought of as algae (dinoflagellates, euglenids, and cryptomonads). Some of the amoebae revert to flagellated forms for part of their life history or have non-functional flagella attached to their bodies.

Many parasites which affect human health or economy are flagellates. They include the relatively benign Giardia and the more damaging trypanosomes and leishmaniases. Flagellates are the major consumers of primary and secondary production in aquatic ecosystems - consuming bacteria and other protists and ensuring the recycling of limiting nutrients.

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marine flagellates

A variety of marine flagellates from the genera (left to right) Cryptaulax, Abollifer, Bodo, Rhynchomonas, Kittoksia, Allas, and Metromonas.
Drawings by Naja Voers.

Flagella arose early in eukaryote evolution, and we are not able to identify any groups of protists which are primitively without flagella.

Eukaryotic flagella are not the same as flagella of bacteria. They have an internal structure comprised of nine doublets of microtubules forming a cylinder around a central pair of microtubules. The peripheral doublets are linked to each other by proteins. These proteins include dynein, a molecular motor which can cause flagella to bend and propel the cell relative to its environment, or propel water or mucus relative to the cell. Many protists have embellishments within or on the outer surface of the flagellum (see electron-micrographs below ). There may be one, two or many flagella. Flagella in rows are said to occur in kineties. Cilia of ciliates and metazoa are a special type of flagellum, organized such that many flagella in kineties (= cilia) may work in synchrony.

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Ploeotia

Ploeotia (Euglenozoa, Euglenida, a heterotrophic euglenid common in marine sediments, showing anterior (to the left) and posterior flagella. Flagella in euglenids are thicker than in many other eukaryotes because of the presence of an additional rod within the flagellum (the crystalline structure within the flagellum to the right below), and because there is a thick coating of fine hairs on the outside.

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Electron micrographs of Chilomastix cuspidata (excavates, retortamonads) and of Entosiphon sulcatum (Euglenozoa, Euglenida). The "9+2" axoneme and the enclosing membrane can be seen in both micrographs, the flagellum of Chilomastix has two vanes, and that of Entosiphon has a crystalline structure lying alongside the axoneme.

The flagellated body form is the most widely exploited among the eukaryotes. The tables below summarise the diversity of HETEROTROPHIC flagellates, and further flagellated taxa are encountered in some of the algal groups

Groups of Flagellates

GROUP CIRCUMSCRIPTION - EXAMPLES HABITAT OF FREE-LIVING SPECIES FOOD OF FREE-LIVING SPECIES PARASITE?
Ancyromonas genus of heterotrophic flagellates marine, freshwater and terrestrial bacteria free-living
Apusomonads several genera of heterotrophic flagellates, Apusomonas, Amastigomonas marine, freshwater and terrestrial bacteria free-living
Cercomonads several genera of heterotrophic flagellates, Cercomonas, Heteromita, Massisteria marine, freshwater and terrestrial bacteria free-living
Collodictyon genus of heterotrophic flagellates free-living protists free-living
Cryothecomonas genus of heterotrophic flagellates marine bacteria? free-living
Dimorphids several genera of heliozoon-like flagellates, Dimorpha, Tetradimorpha marine, freshwater bacteria free-living
Diphylleia genus of heterotrophic flagellates freshwater protists free-living
Discocelis genus of heterotrophic flagellates marine osmotrophic, bacteria free-living
Ebriids several genera of heterotrophic flagellates, ebria, Hermesinum marine protists free-living
Excavates flagellates, diplomonads, jakobids, retortamonads, Trimastix, Carpedediemonas, heterolobosea, etc. marine, freshwater, terrestrial bacteria free-living and parasites
Euglenozoa flagellates, euglenids and kinetoplastids, Peranema, Bodo marine, freshwater, terrestrial bacteria, protists, detritus free-living, a few parasites
Hamates Caecitellus and psedodendromonads (Pseudodendromonas, Cyathomonas), related to stramenopiles marine, freshwater bacteria free-living
Kathablepharids several genera of heterotrophic flagellates marine, freshwater bacteria, protists free-living
Ministeria genus of heterotrophic flagellates marine osmotrophic, bacteria free-living
Multicilia genus of heterotrophic flagellates marine and freshwater bacteria, protists free-living
Oxymonads several genera of heterotrophic flagellates, Oxymonas endobionts
Parabasalids several genera of parasitic heterotrophic flagellate, Trichomonas free-living taxa in marine, soils and freshwater habitats mostly endobionts, but a few free-living
Pelobionts several genera of amitochondriate flagellates marine, freshwater, soils osmotrophic, bacteria, detritus free-living, a few parasites
Phalansterium genus of heterotrophic flagellates freshwater bacteria free-living
Plasmodiophorids parasitic flagellates freshwater, soils pathogenic
Spironemids several genera of heterotrophic flagellates, Spironema, Hemimastix, Stereonema freshwater, soils bacteria free-living
Spongomonads several genera of heterotrophic flagellates, Spongomonas, Rhipidodendron freshwater, soils bacteria free-living
Stephanopogon genus of heterotrophic flagellates marine bacteria, detritus, protists free-living
Telonema genus of heterotrophic flagellates marine protists predatory
Thaumatomonads several genera of heterotrophic flagellates, Thaumatomastix, Protaspis freshwater, marine, soils bacteria, detritus, protists free-living
Heterotrophic flagellates are also found in the following taxa:
Alveolates heterotrophic dinoflagellates
Colpodella
freshwater and marine bacteria, other protists free-living, parasitic and syymbiotic
Cryptomonads Goniomonas and Chilomonas freshwater, soils and marine bacteria, osmotrophs free-living only
Opisthokonts Choanoflagellates freshwater, soils, marine bacteria free-living only
Stramenopiles bicosoecids, proteromonads, opalines, heterotrophic chrysophytes, pedinellids freshwater and marine bacteria, osmotrophs free-living and parasitic
Viridaeplantae Polytoma, Polytomella and a few other genera freshwater osmotrophs free-living

Genera of flagellates for which ultrastructural studies have yet to be carried out, and whose ultrastructural identity is therefore still unknown (after Patterson, 1999)

  • Acinetactis
  • Allantion
  • Allas
  • Alphamonas
  • Amphimonas
  • Artodiscus
  • Aulomonas
  • Bodomorpha
  • Bodopsis
  • Bordnamonas
  • Campanoeca
  • Cladomonas
  • Clautriavia
  • Codonoeca
  • Cruzella
  • Cyathomonas
  • Cyclomonas
  • Dallingeria
  • Dimastigamoeba
  • Dingensia
  • Dinoasteromonas
  • Dinomonas
  • Diplocalium
  • Diplomita
  • Diploselmis
  • Errera
  • Fromentella
  • Heliobodo
  • Kamera
  • Kiitoksia
  • Macappella
  • Metopion
  • Metromonas
  • Microcometes
  • Micromonas
  • Monochrysis
  • Parabodo
  • Paramastix
  • Paramonas
  • Peltomonas
  • Phanerobia
  • Phloxamoeba
  • Phyllomitus
  • Phyllomonas
  • Platytheca
  • Pleurostomum
  • Quadricilia
  • Proleptomonas
  • Rhizomonas
  • Rigidomastix
  • Sainouron
  • Salpingorhiza
  • Schewiakoffia
  • Stenocodon
  • Stephanomonas
  • Toshiba
  • Trichonema

References

Azam, F., Fenchel, T. Field, J.G., Gray, J.S., Meyer-Reil, L.A. & Thingstad, F. 1983. The ecological role of water-column microbes in the sea. Marine Ecol. Progr. Ser, 10: 257-263.

Cavalier-Smith, T. (1981). Eukaryotic kingdoms: seven or nine? Biosystems, 14: 461-481.

Cavalier-Smith, T. 1991. Cell diversification in heterotrophic flagellates. In: Patterson, D.J. & Larsen, J. (eds), The Biology of Free-Living Heterotrophic Flagellates. Oxford University Press, Oxford. pp 113-131.

Cavalier-Smith, T. 1995. Zooflagellate phylogeny and classification, Cytology, 37: 1010-1029

Copeland, H. F. 1956. Classification of the Lower Organisms. Pacific Books, Palo Alto, California.

Corliss, J.O. 1984. The Kingdom Protista and its 45 phyla. BioSystems 17: 87-126

Cox, E.R. 1980. Phytoflagellates. Elsevier North Holland, New York.

Dodge, J.D. 1973. The Fine Structure of Algal Cells, Academic Press, London.

Fenchel, T. 1986b. The Ecology of Protozoa. Madison/Springer-Verlag, Berlin.

Fenchel, T. 1991. Flagellates design and function. In: Patterson, D.J. & Larsen, J. (eds), The Biology of Free-Living Heterotrophic Flagellates. Clarendon Press, Oxford, 7-19.

Larsen, J. & Patterson, D. J. 1990. Some flagellates (Protista) from tropical marine sediments. J. Nat. Hist., 24: 801-937.

Margulis L., Corliss J.O., Melkonian, M. and Chapman D.J. 1990. Handbook of Protoctista. Jones and Bartlett Publishers, Boston.

Moestrup, O. 1982. Flagellar structure in algae: a review, with new observations particularly on the Chrysophyceae, Phaeophyceae (Fucophyceae), Euglenophyceae, and Reckertia. Phycologia, 21: 427-528.

Patterson, D. J. & Larsen, J. (eds) 1991. The Biology of Free-Living Heterotrophic Flagellates, Clarendon Press, Oxford.

Taylor, F.J.R. 1976. Flagellate phylogeny: A study in conflicts. J. Protozool., 23: 28-40.

About This Page

David J. Patterson
Marine Biological Laboratory, Woods Hole, Massachusetts, USA

Page: Tree of Life Flagellates: Heterotrophic Protists With Flagella Authored by David J. Patterson. The TEXT of this page is licensed under the Creative Commons Attribution License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

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