Centroplasthelida Febvre-Chevalier and Febvre, 1984
Diagnosis: Phagotrophic and non-photosynthetic protists with one large spherical or near spherical centrosome at the center of the cell and numerous radiating axopodia. Axopodia always with extrusomes that are either kinetocysts or tiny dense ellipsoids.
Two are clades are distinguished:
Panacanthocystida Shishkin et Zlatogursky, 2018
Diagnosis: Centrohelids usually covered with siliceous scales or with organic spicules: scale-bearing species with both inner plate scales and outer scales of other morphology or only plate scales with a hollow inrolled margin; outer scales may be of different types based on archetype of plate scale morphology or radially symmetrical, present in one of two forms: funnel-shaped, or needle-like with a radially symmetrical base.
Pterocystida Cavalier-Smith and Heyden, 2007 stat. n.
Phylogenetic diagnosis: The least inclusive clade, containing Pterocystis devonica, Raphidiophrys heterophryoidea and Choanocystis curvata, but not Acanthocystis nichollsi.