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:
(unranked):
Phylum:
Class:
Order:
Oxymonadida

Grassé 1952 emend. Cavalier-Smith 2003
Families
Synonyms
  • Oxymonadales
  • Polymastigales Engler 1898
  • Polymastigida Calkins 1902
  • Polymastigina Blochmann 1895
  • Polymastigoda Seligo 1886
  • Pyrsonymphales
  • Pyrsonymphida Grassé 1952

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

Characteristics edit

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 edit

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 edit

Cladogram of Oxymonadida[3]

Polymastigidae

Saccinobaculidae

Oxymonadidae

Opisthomitus

Pyrsonymphidae

  • Order Oxymonadida Grassé 1952 emend. Cavalier-Smith 2003[4]
    • Family Oxymonadidae Kirby 1928 [Oxymonadaceae; Oxymonadinae Cleveland 1934]
    • Family Polymastigidae Bütschli 1884 [Polymastiginae Kirby 1931; Polymastigaceae; Streblomastigaceae; Streblomastigidae Kofoid & Swezy 1919]
    • Family Pyrsonymphidae Grassé 1892 [Pyrsonymphaceae; Pyrsonymphinae Kirby 1937 nom. nud.; Dinenymphidae Grassé 1911; Dinenymphinae Cleveland et al. 1934; Dinenymphaceae]
      • Genus Dinenympha Leidy 1877 [Pyrsonympha (Dinenympha) (Leidy 1877) Koidzumi 1921]
      • Genus Pyrsonympha Leidy 1877 [Pyrsonema Kent 1881; Lophophora Comes 1910 non Coulter 1894 non Kraatz 1895 non Moeschler 1890]
    • Family Saccinobaculidae Brugerolle & Lee 2002 ex Cavalier-Smith 2012 [Saccinobaculinae Cleveland et al. 1934]

References edit

  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. ^ Treitlia, Sebastian C.; Kotykb, Michael; Yubukia, Naoji; Jirounkováa, Eliska; Vlasáková, Jitka; Smejkalováa, Pavla; Sípek, Petr; Cepicka, Ivan; Hampl, Vladimír (2018). "Molecular and Morphological Diversity of the Oxymonad Genera Monocercomonoides and Blattamonas gen. nov". Protist. 169 (5): 744–783. doi:10.1016/j.protis.2018.06.005.
  4. ^ "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.