The retortamonads are a small group of

flagellate A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and thei ...

s, most commonly found in the intestines of animals as

commensals Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit fro ...

, although a free-living species called the ''Chilomastix cuspidata'' exists. They are grouped under the taxon, Archezoa. They are usually around 5-20 μm in length, and all of their small subunit ribosomal RNA gene sequences are very similar to each other. There are two genera: ''

Retortamonas ''Retortamonas'' is a genus of flagellated excavates.Geiman, Q. M. 1932: Retortamonas caudacus (n. sp.), an Intestinal Flagellate from a Beetle Larva, Gyrinidae sp. Transactions of the American Microscopical Society 51(4), 219-224. Doi: DOI: 10 ...

'' with two flagella, and ''

Chilomastix ''Chilomastix'' is a genus of pyriform excavates within the family Retortamonadidae All species within this genus are flagellated, structured with three flagella pointing anteriorly and a fourth contained within the feeding groove. ''Chilomasti ...

'' with four. In both cases there are four

basal bodies A basal body (synonymous with basal granule, kinetosome, and in older cytological literature with blepharoplast) is a protein structure found at the base of a eukaryotic undulipodium ( cilium or flagellum). The basal body was named by Theodor ...

anterior to a prominent feeding groove, and one flagellum is directed back through the cell, emerging from the groove. The retortamonads lack mitochondria, golgi apparatus, dictyosomes, and peroxisomes. They are close relatives of the diplomonads, and are placed among 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 as ...

s along with them. Due to the abundant phylogenetic similarities between the two flagellates, since diplomonads do not ancestrally lack mitochondrion, this suggests that retortamonads are also secondarily amitochondriate.

References

Further reading