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.
Apolimia
A. rotundistoma, from Korganova, 1987 Genus Apolimia Korganova, 1987 Diagnosis: Shell ovoid, quite large, opaque, round in cross section, densely covered with round or oval