Nucleariida is a group of amoebae[1] with filosepseudopods, known mostly from soils and freshwater. They are distinguished from the superficially similar vampyrellids mainly by having mitochondria with discoidcristae, in the absence of superficial granules, and in the way they consume food.
Classification
Molecular studies indicate that nucleariids are closely related to fungi.[2][3] and more distantly to the lineage that gave rise to choanoflagellates and metazoa opisthokonts,[4] the group which includes animals, fungi. Some use a broad definition of Opisthokonta to include all of these organisms with flattened mitochondrial cristae.
The genera Rabdiophrys, Pinaciophora, and Pompholyxophrys, freshwater forms with hollow siliceous scales or spines, were included in Nucleariida by some.[5][6] This was disputed by Smith and Chao who placed them in the Rhizaria.[7] Their affinity with the nucleariids has been confirmed.[8] Historically, nucleariids were included among the heliozoa as the Rotosphaerida because both they and heliozoa had rounded bodies and radiating pseudopodia.
According to a 2009 paper, Fonticula, a cellular slime mold, is an opisthokont and more closely related to Nuclearia than to fungi.[9]
Characteristics
Nucleariids (Nuclearia[4]) are usually small, up to about 50 μm in size.
References
^Zettler; Nerad, T.; O'Kelly, C.; Sogin, M. (May 2001). "The nucleariid amoebae: more protists at the animal-fungal boundary". The Journal of Eukaryotic Microbiology. 48 (3): 293–297. doi:10.1111/j.1550-7408.2001.tb00317.x. PMID11411837. S2CID44548329.
^ abYoshida M, Nakayama T, Inouye I (January 2009). "Nuclearia thermophila sp. nov. (Nucleariidae), a new nucleariid species isolated from Yunoko Lake in Nikko (Japan)". European Journal of Protistology. 45 (2): 147–155. doi:10.1016/j.ejop.2008.09.004. PMID19157810.
^Patterson DJ (May 1985). "On the Organization and Affinities of the Amoeba, Pompholyxophrys punicea Archer, Based on Ultrastructural Examination of Individual Cells from Wild Material 1". J. Protozool. 32 (2): 241–6. doi:10.1111/j.1550-7408.1985.tb03044.x.
^Patterson, D.J.; Simpson, A.G.B.; Rogerson, A. (2002). "Amoebae of uncertain affinities". In Lee, J.J.; Leedale, G.F.; Bradbury, P. (eds.). An Illustrated Guide to the Protozoa (2nd ed.). Lawrence KA: Society of Protozoologists. pp. 804–827. ISBN1-891276-22-0. OCLC49191284.
^Cavalier-Smith, Thomas; Chao, Ema E. (July 2012). "Oxnerella micra sp. n. (Oxnerellidae fam. n.), a Tiny Naked Centrohelid, and the Diversity and Evolution of Heliozoa". Protist. 163 (4): 574–601. doi:10.1016/j.protis.2011.12.005. PMID22317961.