Arcellinid testate amoebae are commonly found in soils, leaf litter, peat bogs and near/in fresh water.
However a recent review suggests that sexual recombination may be the rule rather than the exception in amoeboid protists in general, including the Arcellinid testate amoebae.
The tests lie outside the cell membrane and consist of organic or mineral materials that are either secreted or incorporate external particles.
[6] Fossils of arcellinid testate amoebae date back to the Tonian stage of the Proterozoic, around 789-759 million years ago.
Phryganellina Organoconcha Volnustoma Hyalospheniformes Excentrostoma Sphaerothecina Longithecina Phryganellina Organoconcha Volnustoma Hyalospheniformes Excentrosoma Cylindrothecina Longithecina Sphaerothecina The classification of Arcellinida, as of 2019:[12][5][10] Arcellinida incertae sedis: