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archamoebae

{{Short description|Phylum of protists}}

{{Automatic taxobox

| fossil_range =

| image = Entamoeba histolytica.jpg

| image_caption = Entamoeba histolytica trophozoite

| display_parents = 4

| taxon = Archamoebea

| parent_authority = Cavalier-Smith 1998

| authority = Cavalier-Smith 1993, sensu Cavalier-Smith 2004

| subdivision_ranks = Orders and families

| subdivision=

| synonyms_ref =

| synonyms =

  • Karyoblastea Margulis & Schwartz 1982
  • Peloflagellatea Goodkov & Seravin 1991
  • Caryoblastea
  • Entamoebea Cavalier-Smith 1991
  • Rhizoflagellata Saville Kent 1880
  • Mastigamoebomonada Starobogatov & Seravin 1980

}}

The Archamoebae are a group of protists originally thought to have evolved before the acquisition of mitochondria by eukaryotes.{{cite book|title=The Evolution of Parasitism - A Phylogenetic Perspective |isbn=9780080493749 |editor=Littlewood T |vauthors=Williams BP, Keeling PJ |url=https://books.google.com/books?id=_fAQGEJobT0C&q=Archamoebae&pg=PA30 |access-date=20 February 2018 |pages=30–31|date=2003-12-09 }} They include genera that are internal parasites or commensals of animals (Entamoeba and Endolimax). A few species are human pathogens, causing diseases such as amoebic dysentery. The other genera of archamoebae live in freshwater habitats and are unusual among amoebae in possessing flagella. Most have a single nucleus and flagellum, but the giant amoeba Pelomyxa has many of each.

Description

Archamoebae are a diverse group of amoebae. Many have flagella for motility, while others do not. They grow in the absence of oxygen, though some can tolerate small amounts. Most described species of Archamoebae either lack mitochondria or are described to have reduced mitosomes.{{cite journal|doi=10.1016/j.protis.2012.11.005|pmid=23312407|title=Evolution of Archamoebae: Morphological and Molecular Evidence for Pelobionts Including Rhizomastix, Entamoeba, Iodamoeba, and Endolimax|journal=Protist|volume=164|issue=3|pages=380–410|year=2013|last1=Ptáčková|first1=Eliška|last2=Kostygov|first2=Alexei Yu|last3=Chistyakova|first3=Lyudmila V|last4=Falteisek|first4=Lukáš|last5=Frolov|first5=Alexander O|last6=Patterson|first6=David J|last7=Walker|first7=Giselle|last8=Cepicka|first8=Ivan}}

Habitat

They thrive and live in soil, freshwater, and marine habitats.

History

The group Archamoebae was proposed by Thomas Cavalier-Smith in 1998 as part of the Archezoa, a newly-proposed group to include eukaryotes that had diverged before acquisition of mitochondria and other common eukaryotic cell features.{{cite journal |author=Cavalier-Smith T |title=A revised six-kingdom system of life |journal=Biol Rev Camb Philos Soc |volume=73 |issue=3 |pages=203–66 |date=August 1998 |pmid=9809012 |doi= 10.1111/j.1469-185X.1998.tb00030.x|s2cid=6557779 }}{{cite journal|url=http://www3.botany.ubc.ca/keeling/PDF/98King.pdf |access-date=20 February 2018 |title=A kingdom's progress: Archezoa and the origin of eukaryotes |author=Keeling PJ |journal=BioEssays |volume=20 |pages=87–95 |doi=10.1002/(sici)1521-1878(199801)20:1<87::aid-bies12>3.0.co;2-4|year=1998 }} Early molecular trees based on rRNA supported this position, placing several Archamoebae genera as separate groups that diverged from other eukaryotes very early on, suggesting that the absence of mitochondria was a primitive condition. However, soon thereafter genetic remnants of mitochondria were found in various Archamoebae, suggesting that these organisms had diverged after the evolution of mitochondria, but had lost their mitochondria over time, and are more closely related to various amoebae and slime molds.

Phylogeny

The following cladogram summarizes the known relationships between the different families of Archamoebae.

{{clade|label1=Archamoebae|1={{clade|label1=Entamoebida|1=Entamoebidae|label2=Pelobiontida|2={{clade|label1=Mastigamoebina|label2=Pelomyxina|1={{clade|1=Mastigamoebidae|2=Rhizomastixidae}}|2=Pelomyxidae}}}}}}

Taxonomy

Infraphylum Archamoebae Cavalier-Smith 1993 stat. nov. 1998{{cite journal | vauthors = Cavalier-Smith T, Chao EE, Lewis R | title = 187-gene phylogeny of protozoan phylum Amoebozoa reveals a new class (Cutosea) of deep-branching, ultrastructurally unique, enveloped marine Lobosa and clarifies amoeba evolution | journal = Molecular Phylogenetics and Evolution | volume = 99 | pages = 275–296 | date = June 2016 | pmid = 27001604 | doi = 10.1016/j.ympev.2016.03.023 | doi-access = free }}{{cite book | date=2016| last = Silar | first = Philippe | name-list-style = vanc | chapter = Protistes Eucaryotes: Origine, Evolution et Biologie des Microbes Eucaryotes| url=https://hal.archives-ouvertes.fr/hal-01263138|pages=1–462 | title = HAL archives-ouvertes | isbn = 978-2-9555841-0-1 | chapter-url = https://hal.archives-ouvertes.fr/hal-01263138/file/Protistes_Eucaryotes.pdf }}{{cite journal | vauthors = Kang S, Tice AK, Spiegel FW, Silberman JD, Pánek T, Cepicka I, Kostka M, Kosakyan A, Alcântara DM, Roger AJ, Shadwick LL, Smirnov A, Kudryavtsev A, Lahr DJ, Brown MW | display-authors = 6 | title = Between a Pod and a Hard Test: The Deep Evolution of Amoebae | journal = Molecular Biology and Evolution | volume = 34 | issue = 9 | pages = 2258–2270 | date = September 2017 | pmid = 28505375 | pmc = 5850466 | doi = 10.1093/molbev/msx162 }}{{cite journal | vauthors = Pánek T, Zadrobílková E, Walker G, Brown MW, Gentekaki E, Hroudová M, Kang S, Roger AJ, Tice AK, Vlček Č, Čepička I | display-authors = 6 | title = First multigene analysis of Archamoebae (Amoebozoa: Conosa) robustly reveals its phylogeny and shows that Entamoebidae represents a deep lineage of the group | journal = Molecular Phylogenetics and Evolution | volume = 98 | pages = 41–51 | date = May 2016 | pmid = 26826602 | doi = 10.1016/j.ympev.2016.01.011 | doi-access =free }}

Archamoebae incertae sedis

References

{{Reflist}}

{{Eukaryota}}

{{Amoebozoa}}

{{Amoebozoa diseases}}

{{Taxonbar|from=Q589993}}

Category:Conosa

Category:Infraphyla

Category:Taxa named by Thomas Cavalier-Smith

{{Amoebozoa-stub}}