(hex-a-mite-a), a free living diplomonad flagellate. Diplomonads are so-called because most members of the group have two nuclei, and have clusters of up to 4 flagella emerging from opposing sides of the cell. They arise in grooves, which are believed to correspond to the ventral grooves of the excavate flagellates. Normally associated with anoxic habitats. Diplomonads are probably best known because one their members, Giardia
, is significant as a parasite of the intestinal system, and because it is prominent in studies on the evolution of eukaryotic cells - "clinging resolutely" to the base of the eukaryotic tree as our best candidate for the most primitive eukaryote. The two nuclei are at the anterior (top) and the junction between them is seen as a dark line. The flagellar grooves and some of the flagella are evident. Phase contrast.