Family Lamtopyxidae Bonnet, 1974
Diagnosis: Test with flat sole, bilaterally symmetrical due to its elliptical internal opening at the end of a deeply invaginated tube; the external aperture is bordered by large teeth.
This family is believed to be intermediate between Cyclopyxis and Distomatopyxis (Bonnet, 1979a).
Genus Lamtopyxis Bonnet, 1974
Diagnosis: In dorsal and lateral view like Cyclopyxis puteus but external opening with 3 to 5 teeth. At its base the apertural tube is reinforced by a more or less quadratic organic frame; the internal opening is bordered by a collar. The test is composed of flat mineral particles which are held together by an unstructured organic cement giving the shell a smooth surface as in Cyclopyxis,
All 5 species were described from tropical forest soils. Ref. Bonnet (1974c).
Type species: Lamtopyxis callistoma Bonnet, 1974.