Archezoa

Archezoa was a kingdom proposed by Cavalier-Smith for eukaryotes that diverged before the origin of mitochondria. At various times, the pelobionts and entamoebids (now archamoebae), the metamonads, and the microsporidia were included here. These groups appear near the base of eukaryotic evolution on rRNA trees. However, all these groups are now known to have developed from mitochondrial ancestors, and trees based on other genes do not support their basal placement. The kingdom Archezoa has therefore been abandoned.

The Parasitic Protozoa, Archaezoa has several distinguishing features. They most commonly have two nuclei, eight flagella and do not go through the encysting stage. They can cause Giardial enteritis, Urethritis and Vaginitis if there is fecal contamination of drinking water or contact with vaginal-urethral discharge.