Family Sphenoderiidae Chatelain et al, 2013

Diagnosis: Testate amoeboid organisms with a test covered with self-secreted circular to elliptical silica scales that can be of different sizes and shapes, but without indentations. The pseudostome is surrounded with small round or oval scales. Because usually one side (“ventral”) of the aperture is shorter, the opening lies sub-terminal.

Two genera: Sphenoderia and Trachelocorythion
Type genus: Sphenoderia