Entamoeba
The entamoebae are a group of parasitic and commensal amoebae which lack mitochondria. They include several species that are pathenogenic in humans, most notably Entamoeba histolytica, which causes amoebic dysentery. Cells are uninucleate and small, typically 10-100 μm across, and usually have a single lobose pseudopod taking the form of a clear anterior bulge. Cysts are common.The absence of mitochondria is considered a secondary loss, possibly associated with their parasitic life-cycle. Studies show the entamoebae are close relatives of the pelobionts, another group of amitochondriate amoebae, but unlike them retain dictyosomess. Both groups may belong among the Amoebozoa.