Taxonomy
* Order Trimastigida Cavalier-Smith 2003 ** Family Trimastigidae Saville Kent 1880 *** Genus ''Trimastix'' Saville Kent 1880 **** Species '' T. elaverinus'' Dumas 1930 **** Species '' T. inaequalis'' Bernard, Simpson & Patterson 2000 **** Species '' T. marina'' Kent 1880History of Knowledge
''Trimastix'' were first described by William Kent in 1881 when he observed a ''Trimastix'' cell in a sample sourced from decaying fuci seaweed. He described the genera at the time as free-swimming naked animalcules that are oval, or pear shaped, with a membranous border and three flagella inserted on the anterior end. Kent observed one flagellum facing forwards and two facing backwards. It was also noted in this account that ''Trimastix'' had a visually apparent nucleus and contractile vacuole but no visual oral aperture. Kent determined that ''Trimastix'' was a distinct genus, despite similarities to ''Dallingeria'', because of the lateral border he observed which was not present in ''Dallingeria''. It was later determined that the lateral border Kent was referring to was in fact the oral aperture of ''Trimastix'', which also contained a fourth flagella. Today, the morphology of ''Trimastix'' is better understood, including details not initially observed by Kent, such as Trimastix lacking a conventional mitochondrion.Zubáčová, Z., Novák, L., Bublíková, J., Vacek, V., Fousek, J., Rídl, J., Tachezy J, Doležal P, Vlček C, & Hampl, V. (2013). The mitochondrion-like organelle of ''Trimastix pyriformis'' contains the complete glycine cleavage system. ''PLoS One'', 8(3). Current research indicates that despite there being no strong evidence that the organelle can produce ATP, there are many mitochondrial functions that it appears to have maintained.Habitat and Ecology
''Trimastix'' can only survive in anaerobic habitats, but unlike many amitochondriate anaerobes, ''Trimastix'' are not generally parasitic. ''Trimastix'' instead consume bacteria through their ventral groove. In order to maintain an anoxic environment without parasitism or endosymbiosis, ''Trimastix'' are most often found inside the tissues of dead and decaying marine vegetation.Morphology
''Trimastix'' cells are oblong broad anteriorly and taper posteriorly. ''Trimastix'' is 20 µm long and 8 µm wide. A kinetid of four flagella is located on the anterior end of the cell with one flagella anteriorly oriented, two flagella posteriorly oriented, and the fourth flagella sitting within an oral groove on the ventral side.O’Kelly, C. J., Farmer, M. A., & Nerad, T. A. (1999). Ultrastructure of Trimastix pyriformis (Klebs) Bernard et al.: similarities of Trimastix species with retortamonad and jakobid flagellates. Protist, 150(2), 149-162. ''Trimastix'' species do not have mitochondria, but they do have remnants of an ancestral mitochondria, in the form of aReferences
{{Taxonbar, from=Q622727 Metamonads Excavata genera