Heterophryidae Poche 1913, emend.  Cavalier-Smith and Von der Heyden, 2007


Diagnosis: Centrohelids lacking silica scales, but with numerous thin pointed organic scales tapering towards acute apices. 18S rRNA long and with seven expansion segments not found in Heterophryidae.
Type and sole genus Heterophrys Archer.
Type species H. myriopoda Archer 1868.


Remarks: Sequence data are needed for the other two nominate species (H. minuta, H. simplex) to see if they also belong here. As Heterophryidae are polyphyletic, Chlamydaster, Oxnerella (a completely naked genus with no scales or mucous coat, formerly also included in the family), and H. marina are now excluded.


Key for genera and species of the family Heterophryidae



Spicules lie mainly in tangential direction

Sphaerastrum fockei


Spicules lie mainly in radial direction

Heterophrys > 2


Cell at the top of a mucous stalk H. febvre-chevalierae


Mucous stalk is absent



Radial spicules with rough surface

H. simplex


Radial spicules with smooth surface



Spicules c. half of the cell diameter in length, tapering from bases to sharp apices

H. myriopoda


Spicules are ca. the cell diameter in length and of uniform width

H. marina