Apusozoa

{{Short description|Phylum of micro-organisms}}

{{For|the monophyletic counterpart|Obazoa}}

{{Paraphyletic group

| auto = yes

| display_parents = 3

| image = Apusomonas.png

| image_alt = Apusomonas sp.

| image_caption = Apusomonas sp.

| taxon = Apusozoa

| authority = Cavalier-Smith 1997 emend. 2013

| includes =

• Thecomonadea
• Breviatea

| excludes =

• Opisthokonta

| color_as = Eukaryota

| classification_status = obsolete

}}

The Apusozoa are a paraphyletic phylum{{cite journal |vauthors=Cavalier-Smith T, Chao EE, Stechmann A, Oates B, Nikolaev S |title=Planomonadida ord. nov. (Apusozoa): ultrastructural affinity with Micronuclearia podoventralis and deep divergences within Planomonas gen. nov |journal=Protist |volume=159 |issue=4 |pages=535–62 |date=October 2008 |pmid=18723395 |doi=10.1016/j.protis.2008.06.002 }} of flagellate eukaryotes. They are usually around 5–20 μm in size, and occur in soils and aquatic habitats, where they feed on bacteria. They are grouped together based on the presence of an organic shell or theca under the dorsal surface of the cell.

The name derives from the Ancient Greek words for footless ({{Lang|el|ἄπους}}) and animal ({{Lang|el|ζῷον}}).{{LSJ|apous|ἄπους|cite}}{{LSJ|zwon|ζῷον|cite}}

This phylum was defined as containing the Breviata and the Apusomonadida.{{Cite journal|last1=Eme|first1=Laura|last2=Sharpe|first2=Susan C.|last3=Brown|first3=Matthew W.|last4=Roger|first4=Andrew J.|date=2014-08-01|title=On the Age of Eukaryotes: Evaluating Evidence from Fossils and Molecular Clocks|journal=Cold Spring Harbor Perspectives in Biology|language=en|volume=6|issue=8|pages=a016139|doi=10.1101/cshperspect.a016139|issn=1943-0264|pmid=25085908|pmc=4107988}}{{Cite journal|last1=Ruggiero|first1=Michael A.|last2=Gordon|first2=Dennis P.|last3=Orrell|first3=Thomas M.|last4=Bailly|first4=Nicolas|last5=Bourgoin|first5=Thierry|last6=Brusca|first6=Richard C.|last7=Cavalier-Smith|first7=Thomas|last8=Guiry|first8=Michael D.|last9=Kirk|first9=Paul M.|date=2015-06-11|title=Correction: A Higher Level Classification of All Living Organisms|journal=PLOS ONE|volume=10|issue=6|pages=e0130114|doi=10.1371/journal.pone.0130114|pmid=26068874|pmc=5159126|bibcode=2015PLoSO..1030114R|issn=1932-6203|doi-access=free}} However, it is viewed as paraphyletic, with the Breviata as more basal. The opisthokonts appear to have emerged as sister of the Apusomonadida. It has been suggested that the Mantamonadida be classified in Apusozoa.{{cite journal|date=September 2010|title=The Novel Marine Gliding Zooflagellate Genus Mantamonas (Mantamonadida ord. n.: Apusozoa)|journal=Protist|volume=162|issue=2|pages=207–221|doi=10.1016/j.protis.2010.06.004|pmid=20884290|vauthors=Glücksman E, Snell EA, Berney C, Chao EE, Bass D, Cavalier-Smith T}}{{cite bioRxiv|last1=Orr|first1=Russell J. S.|last2=Zhao|first2=Sen|last3=Klaveness|first3=Dag|last4=Yabuki|first4=Akinori|last5=Ikeda|first5=Keiji|last6=Makoto|first6=Watanabe M.|last7=Shalchian-Tabrizi|first7=Kamran|date=2017-10-08|title=Enigmatic Diphyllatea eukaryotes: Culturing and targeted PacBio RS amplicon sequencing reveals a higher order taxonomic diversity and global distribution|biorxiv=10.1101/199125}}

The Ancyromonadida appear to be Varisulca, Planomonadida, shifting them possibly more basal than the Amoebozoa,{{Cite journal|last1=Speijer|first1=Dave|last2=Lukeš|first2=Julius|last3=Eliáš|first3=Marek|date=2015-07-21|title=Sex is a ubiquitous, ancient, and inherent attribute of eukaryotic life|journal=Proceedings of the National Academy of Sciences|language=en|volume=112|issue=29|pages=8827–8834|doi=10.1073/pnas.1501725112|issn=0027-8424|pmid=26195746|pmc=4517231|bibcode=2015PNAS..112.8827S|doi-access=free}}{{Cite journal|last1=Torruella|first1=Guifré|last2=Mendoza|first2=Alex de|last3=Grau-Bové|first3=Xavier|last4=Antó|first4=Meritxell|last5=Chaplin|first5=Mark A.|last6=Campo|first6=Javier del|last7=Eme|first7=Laura|last8=Pérez-Cordón|first8=Gregorio|last9=Whipps|first9=Christopher M.|title=Phylogenomics Reveals Convergent Evolution of Lifestyles in Close Relatives of Animals and Fungi|journal=Current Biology|volume=25|issue=18|pages=2404–2410|doi=10.1016/j.cub.2015.07.053|pmid=26365255|year=2015|doi-access=free}}{{Cite journal|last1=Cavalier-Smith|first1=Thomas|last2=Chao|first2=Ema E.|last3=Snell|first3=Elizabeth A.|last4=Berney|first4=Cédric|last5=Fiore-Donno|first5=Anna Maria|last6=Lewis|first6=Rhodri|title=Multigene eukaryote phylogeny reveals the likely protozoan ancestors of opisthokonts (animals, fungi, choanozoans) and Amoebozoa|journal=Molecular Phylogenetics and Evolution|volume=81|pages=71–85|doi=10.1016/j.ympev.2014.08.012|pmid=25152275|year=2014|doi-access=free}} or less basal.{{Cite journal|last1=Paps|first1=Jordi|last2=Medina-Chacón|first2=Luis A.|last3=Marshall|first3=Wyth|last4=Suga|first4=Hiroshi|last5=Ruiz-Trillo|first5=Iñaki|title=Molecular Phylogeny of Unikonts: New Insights into the Position of Apusomonads and Ancyromonads and the Internal Relationships of Opisthokonts|journal=Protist|volume=164|issue=1|pages=2–12|doi=10.1016/j.protis.2012.09.002|pmid=23083534|pmc=4342546|year=2013}} While some classification systems have placed Hemimastigida in Apusozoa,{{Cite journal|date=2003-01-01|title=Protist phylogeny and the high-level classification of Protozoa|journal=European Journal of Protistology|language=en|volume=39|issue=4|pages=338–348|doi=10.1078/0932-4739-00002|issn=0932-4739|last1=Cavalier-Smith|first1=Thomas}} 2018 research indicated that hemimastigotes ({{ill|Hemimastix kukwesjijk|de}}/Hemimastix/Spironematellidae) are their own supra-kingdom.{{cite news |last1=Chung |first1=Emily |title=Rare microbes lead scientists to discover new branch on the tree of life |url=https://www.cbc.ca/news/technology/hemimastigotes-supra-kingdom-1.4715823 |access-date=16 November 2018 |agency=CBC news |date=November 16, 2018}}