Oxymonad

The oxymonads (or Oxymonadida) are a group of flagellatedprotists found exclusively in the intestines of animals, mostly in termites and other wood-eatinginsects. Along with the similar parabasalid flagellates, they harbor the symbioticbacteria that are responsible for breaking down cellulose. There is no evidence for presence of mitochondria (not even anaerobic mitochondrion-like organelles like hydrogenosomes or mitosomes) in oxymonads and three species have been shown to completely lack any molecular markers of mitochondria.

It includes e.g. Dinenympha, Pyrsonympha, Oxymonas, Streblomastix, Monocercomonoides, and .