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

1Spicules lie mainly in tangential direction

Sphaerastrum fockei

Spicules lie mainly in radial directionHeterophrys > 2
2Cell at the top of a mucous stalkH. febvre-chevalierae
Mucous stalk is absent3
3Radial spicules with rough surfaceH. simplex
Radial spicules with smooth surface4
4Spicules c. half of the cell diameter in length, tapering from bases to sharp apicesH. myriopoda
Spicules are ca. the cell diameter in length and of uniform widthH. marina
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