The oxymonads (or Oxymonadida) are a group of found exclusively in the intestines of animals, mostly and other Xylophagy . Along with the similar parabasalid flagellates, they harbor the Symbiosis bacterium that are responsible for breaking down cellulose. There is no evidence for presence of Mitochondrion (not even anaerobic mitochondrion-like organelles like or ) in oxymonads
It includes e.g. Dinenympha, Pyrsonympha, Oxymonas,
Characteristics
Most Oxymonads are around 50 μm in size and have a single
cell nucleus, associated with four
Flagellum. Their
Basal body give rise to several long sheets of
, which form an organelle called an
axostyle, but different in structure from the axostyles of
. 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 and Paratrimastix
The free-living flagellates
Trimastix and
Paratrimastix are closely related to the oxymonads.
They lack aerobic
Mitochondrion and have four flagella separated by a preaxostyle, but unlike the oxymonads have a feeding groove. This character places the Oxymonads,
Trimastix, and
Paratrimastix among the
Excavata, and in particular they may belong to the
. Molecular phylogenetic studies indeed place
Anaeromonadea (oxymonads,
Trimastix, and
Paratrimastix) in
.
Taxonomy
-
Order Oxymonadida Grassé 1952 emend. Cavalier-Smith 2003
