Description of Argynnia
provided by BioPedia
Shell compressed, aperture surrounded by siliceous plates, giving it a rough outline. Shell greyish, composed of various euglyphid plates, mixed with diatom fragments and mineral particles, porous cement. The structure of the test is intermediate between Nebela and Difflugia. Nucleus: ovular. This genus was proposed by Jung (1942) without type designation and validated by Vucetich (1974) including only three species from the southern hemisphere. Type species: Argynnia schwabei. Here Argynnia is used in a less restricted sense to allow for common and better known species with similar test structure, such as Argynnia dentistoma (Penard, 1890) (Synonym: N. dentistoma). Habitat: A. dentistoma is common in sphagnum or in acid humus other species live in freshwater sediments. Used in this broader sense Argynnia has about fifteen species.
