Nucleariida
Nucleariida is a group of amoebae with pseudopods, known mostly from soils and freshwater. They are distinguished from the superficially similar vampyrellids mainly by having mitochondria with discoid cristae.Classification
Nucleariids are opisthokonts, the group which includes animals, fungi and several smaller groups. Several studies place the nucleariids as a sister group to the fungi.
The genera Rabdiophrys, Pinaciophora, and Pompholyxophrys, freshwater forms with hollow siliceous scales or spines, were formerly included in Nucleariida, but are now placed in Rhizaria. In the past, nucleariids were included among the heliozoa as the Rotosphaerida.
According to a 2009 paper, Fonticula, a cellular slime mold, is an opisthokont and more closely related to Nuclearia than to fungi.Characteristics
Nucleariids are usually small, up to about 50 μm in size.
