Authors include Josef Anton Maximilian Perty,[1] Ernst Haeckel[2] and in the 20th century by Thomas Cavalier-Smith in his classification system.
Like Margulis and others before (see Pelomyxa), Cavalier-Smith argued that the initial ancestor of eukaryotes emerged prior to the endosymbiotic acquisition (see endosymbiosis) of mitochondria.
[10] An argument for the Archezoa group was that amitochondriate protists appeared to branch off early on from the eukaryotic lineage in phylogenetic analyses.
This corroborated the supposition that Archezoa were more closely linked to primitive eukaryotes that evolved prior to the endosymbiotic process that generated the mitochondria.
[3] However, this early divergence later turned out to be a class of systematic errors in phylogenetic analysis called "long branch attraction".