Family Trigonopyxidae Loeblich & Tappan, 1964
Diagnosis: Lobose testate amoebae with circular organic shell covered with fragments of mineral grains, diatoms and organic debris; aperture terminal, circular, oval, crescent-shaped or three or four lobed.
|1||Test in oral view circular||2|
|2||Aperture triangular, three-lobed, or irregular; always with thickened organic rim||Trigonopyxis|
|–||Aperture circular, irregular, crescent-shaped, or with > 5 lobes; never with thickened organic rim||3|
|–||Aperture not crescent-shaped||4|
|–||Aperture not invaginated||Geopyxella|