Oxymonad

The Oxymonads (or Oxymonadida) are a group of flagellated protozoa found exclusively in the intestines of termites and other wood-eating insects. Along with the similar parabasalid flagellates, they harbor the symbiotic bacteria that are responsible for breaking down cellulose.

Oxymonads
Monocercomonoides melolanthae
Scientific classification
Domain:
Eukaryota
(unranked):
Excavata
Phylum:
Metamonada
Subphylum:
Preaxostyla
Class:
Anaeromonadea
Order:
Oxymonadida

Grassé 1952 emend. Cavalier-Smith 2003
Family
  • Oxymonadidae
  • Polymastigidae
  • Pyrsonymphidae
  • Saccinobaculidae
  • Streblomastigidae
Synonyms
  • Oxymonadales
  • Polymastigales
  • Pyrsonymphales

It includes Dinenympha, Pyrsonympha, and Oxymonas.[1]

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, 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 is closely related to the oxymonads.[2] 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, and in particular they may belong to the metamonads.

Taxonomy
  • Order Oxymonadida Grassé 1952 emend. Cavalier-Smith 2003[3]
    • Family Oxymonadidae Kirby 1928 [Oxymonadaceae]
      • Genus ?Barroella Zeliff 1944 [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 [Polymastigaceae]
      • 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 [Pyrsonymphaceae; Dinenymphaceae]
    • 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 [Streblomastigaceae]

References
  1. Moriya S, Dacks JB, Takagi A, et al. (2003). "Molecular phylogeny of three oxymonad genera: Pyrsonympha, Dinenympha and Oxymonas". J. Eukaryot. Microbiol. 50 (3): 190–7. doi:10.1111/j.1550-7408.2003.tb00115.x. PMID 12836875. S2CID 26831383.
  2. Dacks JB, Silberman JD, Simpson AG, et al. (June 2001). "Oxymonads are closely related to the excavate taxon Trimastix". Mol. Biol. Evol. 18 (6): 1034–44. doi:10.1093/oxfordjournals.molbev.a003875. PMID 11371592.
  3. "Part 1- Virae, Prokarya, Protists, Fungi". Collection of genus-group names in a systematic arrangement. Archived from the original on 14 August 2016. Retrieved 30 June 2016.
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