Genus Sphenoderia Schlumberger, 1845
Diagnosis: test clear, circular or ovoid, covered with overlapping elliptical or nearly circular scales. Pseudostome circular or a narrow, oval slit at the end of a broad, clear collar covered with numerous small plates. Nucleus spherical, with few small nucleoli.
Scales of one or more types on the core of the shell, pseudostome slit-like, mostly surrounded by a collar that comprises small scales that can be sometimes invaginated (S.sphaerica). Round or oval cross section (e.g.S. compressa, S. labiata). Occurs from aquatic (S. compressa, S. lenta var. longicollis) to litter and moss environments.
Type species: Sphenoderia lenta.