[4][5] They lack shared morphological characteristics at the microscopic level,[6] and are instead united by molecular phylogenies of rRNA and actin or polyubiquitin.

They are closely related to the phylum Retaria, comprising amoeboids that usually have complex shells, and together form a supergroup called Rhizaria.

They show a variety of forms[9] and have proven difficult to define in terms of structural characteristics, although their unity is strongly supported by phylogenetic studies.

Particularly sarcomonads, with their ability to cyst, feed and multiply within hours, are perfectly adapted to the fluctuating environmental factors in the phyllosphere.

Posterior multigene phylogenetic analyses consistently found Cercozoa to be paraphyletic, because Endomyxa clustered next to Retaria instead of Filosa.

[2] Imbricatea Sarcomonadea Thecofilosea Helkesea Metromonadea Chlorarachnea Granofilosea A more recent phylogenomic analysis recovered both Monadofilosa and Reticulofilosa as monophyletic within the clade Filosa.