An interesting group of testate amoebae is the genus Difflugia. There have been described hundreds of species, but the question is: how many of them are true species? Most descriptions are inaccurate of just based on one single test. Probably this group consists of several genera. Only DNA sequencing can help here. One of my projects is to make a visual map of all known species. It’s one of the most difficult taxa to identify.
Argynnia dentistoma, 117 µm long – Tirol, Austria Genus Argynnia Vucetich, 1974 Diagnosis: Shell compressed, aperture surrounded by siliceous plates, giving it a rough outline.
Family Vexilliferidae Page, 1987 Diagnosis: Amoebae with long, slender subpseudopodia (usually more than one) frequently giving a spiny appearance to the cell. Subpseudopodia from hyaline
Tracheleuglypha dentata, Ecuador (l) and the Netherlands (r) Tracheleuglypha dentata (Vejdovsky, 1882) Diagnosis: test clear, elliptical, round in cross-section; with circular, overlapping scales; no spines
Sphenoderia sphaerica Sphenoderia sphaerica Playfair, 1917 Diagnosis: Test almost spherical, very slightly compressed, side-view ovate-subglobose, end broadly oval; in front-view circular, truncate anteriorly. Pseudostome a