Class Granofilosea Cavalier-Smith and Bass, 2009
Diagnosis: Cercozoa typically with very fine branching or unbranched filopodia bearing obvious granules (extrusomes) at frequent rather regular intervals or with radiating axopodia (sometimes branched) with similar granules; filopodia with internal microtubules, typically appressed to the substratum during feeding, in a semi-immobile state; in most species they do not anastomose but in a few they may, especially between separate cells to form a meroplasmodium (notably in Leucodictyidae; possibly also in Massisteria); characterised species bacterivorous, marine or freshwater. Many have paired centrioles and either two ciliary stubs or two short cilia in the feeding phase or even a distinct flagellate phase (Massisteria marina, probably Limnofila borokensis, Mesofila limnetica, desmothoracids) with one or two long cilia. Golgi dictyosomes paranuclear; ciliary transition region with an axosome at the base of the central pair.
Order 1. Limnofilida Cavalier-Smith and Bass, 2009
Diagnosis: Small freshwater heterotrophic protozoa with extremely slender, branching granular filopodia, appressed to the substratum during feeding. Phylogenetically defined as the largest clade that includes Limnofila but excludes Massisteria. It excludes the phylogenetically distant marine Nanofila which is morphologically similar but with unbranched filopodia.
Family 1. Limnofilidae Cavalier-Smith and Bass, 2009
Diagnosis: trophic phase a small, often globular cell; cilia if present generally not visible in the light microscope; with branched regularly granular and very slender filopodia. Bacterivorous.
Type genus Limnofila Cavalier-Smith and Bass, 2009
Order 2. Leucodictyida Cavalier-Smith, 1993.
Diagnosis: Biciliate marine protists with very slender branching granular filopodia that can fuse temporarily to form meroplasmodia; granules are concentric extrusomes; tubular mitochondrial cristae; large granules in the distal centriolar matrix (a synapomorphy not remarked on before); with (Massisteria) or without (Leucodictyidae: Leucodictyon, Reticulamoeba) obvious paranuclear microbody.
Order 3. Cryptofilida Cavalier-Smith and Bass, 2009
Diagnosis: non-ciliate heterotrophic protists with branching or unbranched granular filopodia appressed to the substratum during feeding. If filopodia branch, cells are larger than Limnofilida.
Family 1. Nanofilidae Cavalier-Smith and Bass fam. n. Diagnosis: tiny non-ciliate marine heterotrophic protists with unbranched granular filopodia appressed to the substratum during feeding. Type genus Nanofila Cavalier-Smith and Bass gen. nov. Diagnosis: tiny non-ciliate marine heterotrophic protists with unbranched granular filopodia appressed to substratum during feeding. Type species Nanofila marina Cavalier-Smith and Bass, 2009
Family 2. Mesofilidae Cavalier-Smith and Bass, 2009
Diagnosis: Biciliate amoeboflagellates with numerous extremely long branching filopodia that in contrast to Heliomorphidae (Tetradimorpha and Heliomorpha — usually known by the invalid names Dimorpha or Dimorphiella) do not radiate in three dimensions from a centrosome but are appressed to the substratum during feeding. Filopodia and long cilia can be present simultaneously or each on their own, depending on the growth phase. Type genus Mesofila Cavalier-Smith and Bass gen. n. Diagnosis as for family Mesofilidae.
Type species Mesofila limnetica Cavalier-Smith and Bass, 2009
Order 4. Clathrulinidae Claus, 1874
Diagnosis: Extracellular capsule or lorica attached to substrate, with axopodia emerging from perforations; kinetocyst extrusomes along axopodia; tubular mitochondrial cristae; biciliated and
amoeboid stages; can be colonial. Cienkowskia, Clathrulina, Hedriocystis.
Order 5. Heliomonadida Cavalier-Smith 1993 ( = Dimorphida Siemensma 1991)
Family Heliomorphidae Cavalier-Smith and Bass, 2009
Diagnosis: Biciliate freshwater heterotrophic Cercozoa with axopodia radiating three dimensionally from a centrosome and supported by microtubules cross-linked in a quincunx pattern; centrioles exceptionally long; axopodia have fairly regularly spaced complex extrusomes with a concentric core. Anterior cilium bears fine hairs in at least one genus; ciliary transition region more complex than in other Granofilosea, with a second distal transverse plate well distal to the centriolar distal partition, a peripheral dense cylinder and axosome. The centrosome is embedded in a deep depression at the anterior end of the nucleus and some axopodial axonemes penetrate the nuclear cup via cytoplasmic channels.
Type genus Heliomorpha Cavalier-Smith and Bass, 2009
Class Proteomyxidea Lankester, 1885 emend. Cavalier-Smith and Bass, 2009
Diagnosis: Naked cercozoan rhizopods with non-granular filopodia or (more usually) reticulopodia; plastids absent; cilia usually absent. Feeding stage uninucleate or multinucleate, sometimes numerous cells form a macroscopic plasmodium. Phagotrophic; feed on bacteria, fungi, algae or small animals. Marine or freshwater or in soil or among mosses or lichens.