Trichomonadida

Trichomonadida is an order of anaerobic protists, included with the parabasalids. Members of this order are referred to as trichomonads. Some organisms in this order include: Trichomonas vaginalis, an organism living inside the vagina of humans Dientamoeba fragilis, parasitic ameboid in humans Histomonas meleagridis, parasite that causes blackhead disease in poultry Mixotricha paradoxa, a symbiotic organism inside termites, host of endosymbionts Anatomy Species in this order typically have four to six flagella at the cell's apical pole, one of which is recurrent - that is, it runs along a surface wave, giving the aspect of an undulating membrane. Like other parabasalids, they typically have an axostyle, a pelta, a costa, and parabasal bodies. In Histomonas only one flagellum and a reduced axostyle are found, and in Dientamoeba, both are absent.