The term/group Myzozoa was not considered in a resolution of protist groups by Adl et al. 2012.[7] Strict taxonomy only considers common traits possessed by all organisms of the group. Some organisms within each of the component groups of Myzozoa have lost the ability for Myzocytosis. Further, as taxonomy pays no account of molecular phylogeny, one current classification has all alveolate taxa other than apicomplexans, ciliates and dinoflagellates, named under the grab bag term "Protalveolata".[7] The difficulty of placing very early dinozoans either within or outside the group "dinoflagellates" continues to favour classifications such as Protalveolata,[7] as does the potential polyphyly between the two genera of "colpodellids" Voromonas and Colpodella.[6]
Evolution
The most closely related large clade to the myzozoans are the ciliates.[1]
Both of these groups of organisms – unlike the majority of eukaryotes studied to date – seem to have a linear mitochondrial genome. Most other eukaryotes that have had their mitochondrial genomes examined have circular genomes. However, the taxonomic term Myzozoa specifically excludes ciliates[1] which are rather under the higher taxonomic rank Alveolata. Thus, Alveoata includes two large groups: Myzozoa and Ciliophora [8] plus the smaller groups discussed above.
All Myzozoa appears to have evolved from an ancestor that possessed plastids, required through endosymbiosis.[9]
The branching order within both Myzozoa and Protalveolata, is only partly understood. Three groups – the Colpodellids, Chromerida and the Apicomplexa – appear to be sister clades.[10] Three other groups – the Perkinsids, Syndiniales and Oxyrrhis are distantly related to the dinoflagellates.[11][12]
^ abCavalier-Smith T, Chao EE (September 2004). "Protalveolate phylogeny and systematics and the origins of Sporozoa and dinoflagellates (phylum Myzozoa nom. nov.)". Eur J Protistol. 40 (3): 185–212. doi:10.1016/j.ejop.2004.01.002.
^ abcAdl SM, Simpson AG, Lane CE, Lukeš J, Bass D, Bowser SS, Brown MW, Burki F, Dunthorn M, Hampl V, Heiss A, Hoppenrath M, Lara E, Le Gall L, Lynn DH, McManus H, Mitchell EA, Mozley-Stanridge SE, Parfrey LW, Pawlowski J, Rueckert S, Shadwick RS, Shadwick L, Schoch CL, Smirnov A, Spiegel FW (2012). "The revised classification of eukaryotes". J. Eukaryot. Microbiol. 59 (5): 429–93. doi:10.1111/j.1550-7408.2012.00644.x. PMC3483872. PMID23020233.
^Muñoz-Gómez, Sergio A.; Slamovits, Claudio H. (2018). "Plastid Genomes in the Myzozoa". Plastid Genome Evolution. Advances in Botanical Research. Vol. 85. pp. 55–94. doi:10.1016/bs.abr.2017.11.015. ISBN9780128134573.
^Leander BS, Kuvardina ON, Aleshin VV, Mylnikov AP, Keeling PJ (2003). "Molecular phylogeny and surface morphology of Colpodella edax (Alveolata): insights into the phagotrophic ancestry of apicomplexans". J. Eukaryot. Microbiol. 50 (5): 334–40. doi:10.1111/j.1550-7408.2003.tb00145.x. PMID14563171.