The Oxymonads (or Oxymonadida) are a group of flagellated protozoa found exclusively in the intestines of

termite Termites are small insects that live in colonies and have distinct castes (eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blatto ...

s and other wood-eating insects. Along with the similar parabasalid flagellates, they harbor the symbiotic

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

that are responsible for breaking down

cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell w ...

. It includes ''

Dinenympha ''Dinenympha'' is a genus of Excavata Excavata is a major supergroup of unicellular organisms belonging to the domain Eukaryota. It was first suggested by Simpson and Patterson in 1999 and introduced by Thomas Cavalier-Smith in 2002 as a for ...

'', '' Pyrsonympha'', and '' Oxymonas''.

Characteristics

Most Oxymonads are around 50 μm in size and have a single nucleus, associated with four flagella. Their basal bodies give rise to several long sheets of microtubules, which form an organelle called an

axostyle An axostyle is a sheet of microtubules found in certain protists. It arises from the bases of the flagella, sometimes projecting beyond the end of the cell, and is often flexible or contractile, and so may be involved in movement and provides suppo ...

, but different in structure from the axostyles of parabasalids. The cell may use the axostyle to swim, as the sheets slide past one another and cause it to undulate. An associated fiber called the preaxostyle separates the flagella into two pairs. A few oxymonads have multiple nuclei, flagella, and axostyles.

Relationship to Trimastix

The free-living flagellate ''

Trimastix ''Trimastix'' is a genus of excavates, the sole occupant of the order Trimastigida. ''Trimastix'' are bacterivorous, free living and anaerobic. When first observed in 1881 by William Kent, the morphology of Trimastix was not well describedKent, ...

'' is closely related to the oxymonads. It lacks mitochondria and has four flagella separated by a preaxostyle, but unlike the oxymonads has a feeding groove. This character places the Oxymonads and ''Trimastix'' among the

Excavata Excavata is a major supergroup of unicellular organisms belonging to the domain Eukaryota. It was first suggested by Simpson and Patterson in 1999 and introduced by Thomas Cavalier-Smith in 2002 as a formal taxon. It contains a variety of free- ...

, and in particular they may belong to the

metamonad The metamonads are microscopic eukaryotic organisms, a large group of flagellate amitochondriate Loukozoa. Their composition is not entirely settled, but they include the retortamonads, diplomonads, and possibly the parabasalids and oxymonads a ...

Taxonomy

* Order Oxymonadida Grassé 1952 emend. Cavalier-Smith 2003 ** Family Oxymonadidae Kirby 1928 xymonadaceae*** Genus ?'' Barroella'' Zeliff 1944 'Kirbyella''_Zeliff_1930_non_Kirkaldy_1906_non_Bolivar_1909.html" ;"title="Kirbyella.html" ;"title="'Kirbyella">'Kirbyella'' Zeliff 1930 non Kirkaldy 1906 non Bolivar 1909">Kirbyella.html" ;"title="'Kirbyella">'Kirbyella'' Zeliff 1930 non Kirkaldy 1906 non Bolivar 1909*** Genus ?''Metasaccinobaculus'' Freitas 1945 *** Genus ?''Tubulimonoides'' Krishnamurthy & Sultana 1976 *** Genus ''Microrhopalodina'' Grassé & Foa 1911 [''Proboscidiella'' Kofoid & Swezy 1926; '' Opisthomitus'' Grassé 1952 non Duboscq & Grassé 1934] *** Genus '' Oxymonas'' Janicki 1915 *** Genus '' Sauromonas'' Grassé & Hollande 1952 ** Family Polymastigidae Bütschli 1884 olymastigaceae*** Genus ?'' Brachymonas'' Grassé 1952 non Hiraishi et al. 1995 *** Genus ?'' Paranotila'' Cleveland 1966 *** Genus '' Monocercomonoides'' Travis 1932 *** Genus '' Polymastix'' Bütschli 1884 non Gruber 1884 ** Family Pyrsonymphidae Grassé 1892 yrsonymphaceae; Dinenymphaceae*** Genus ''

'' Leidy 1877 *** Genus '' Pyrsonympha'' Leidy 1877 'Pyrsonema''_Kent_1881;_''Lophophora.html" ;"title="Pyrsonema.html" ;"title="'Pyrsonema">'Pyrsonema'' Kent 1881; ''Lophophora">Pyrsonema.html" ;"title="'Pyrsonema">'Pyrsonema'' Kent 1881; ''Lophophora'' Comes 1910 non Coulter 1894 non Kraatz 1895 non Moeschler 1890] ** Family Saccinobaculidae Brugerolle & Lee 2002 ex Cavalier-Smith 2012 *** Genus ''Notila'' Cleveland 1950 *** Genus ''Saccinobaculus'' Cleveland-Hall & Sanders & Collier 1934 ** Family Streblomastigidae Kofoid & Swezy 1919 treblomastigaceae*** Genus '' Streblomastix'' Kofoid & Swezy 1920

References

{{Taxonbar, from=Q618894 Flagellates Metamonads