Capsaspora is a monotypic genus containing the single species Capsaspora owczarzaki. C. owczarzaki is a single-celled eukaryote that occupies a key phylogenetic position in our understanding of the origin of animal multicellularity, as one of the closest unicellular relatives to animals. It is, together with Ministeria vibrans, a member of the Filasterea clade (see “Taxonomy” below). This amoeboid protist has been pivotal to unraveling the nature of the unicellular ancestor of animals, which has been proved to be much more complex than previously thought.[3][4][5]
^Hertel L. A.; Bayne C. J.; Loker, E. S. (August 2002), "The symbiont Capsaspora owczarzaki, nov. gen. nov. sp., isolated from three strains of the pulmonate snail Biomphalaria glabrata is related to members of the Mesomycetozoea", International Journal for Parasitology, 32 (9): 1183–91, doi:10.1016/S0020-7519(02)00066-8, PMID12117501
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