Nucleariid

The nucleariids are a small group of amoeboid protists with filose pseudopods, known mostly from soils and freshwater. They are distinguished from the similar vampyrellids mainly by having mitochondria with discoid cristae. The cells are usually small, up to about 50 μm in size. Nuclearia and Vampyrellidium, which are parasitic on and in algae respectively, are naked. The other genera, Rabdiophrys, Pinaciophora, and Pompholyxophrys, are freshwater forms with hollow siliceous scales or spines. These were formerly included among the heliozoa as the Rotosphaerida.