Breviatea
{{Short description|Group of protists}}
{{Automatic taxobox
| taxon = Breviatidae
| authority = Cavalier-Smith, 2013
| grandparent_authority = Cavalier-Smith, 2004
| parent_authority = Cavalier-Smith, 2004
| image = Mastigamoeba_invertens.jpg
| image_caption = Breviata anathema
| display_parents = 5
| subdivision_ranks = Genera
| subdivision =
| diversity = 4 species
}}
Breviatea, commonly known as breviate amoebae, are a group of free-living, amitochondriate protists with uncertain phylogenetic position. They are biflagellate, and can live in anaerobic (oxygen-free) environments. They are currently placed in the Obazoa clade. They likely do not possess vinculin proteins. Their metabolism relies on fermentative production of ATP as an adaptation to their low-oxygen environment.
The lineage emerged roughly one billion years ago, at a time when the oxygen content of the Earth's oceans was low, and they thus developed anaerobic lifestyles. Together with Apusomonads, they are the closest relatives of the Opisthokonts, a group that includes animals and fungi.
Characteristics
Evolution
Breviatea is a clade of basal eukaryotes. They are closely related to the apusomonads and the Opisthokonta supergroup, and together they compose the larger clade Obazoa, which is the sister group to Amoebozoa. Within Breviatea, the four known species are distributed into smaller clades of two species each: one uniting Breviata with Subulatomonas, and one uniting Lenisia with Pygsuia.
{{clade|style=font-size:90%;|label1=Podiata|1={{clade|1=CRuMs|label2=Amorphea|2={{clade|1=Amoebozoa|label2=Obazoa|2={{clade|1={{clade|label1=Breviatea|1={{clade|1={{Clade
}}
|2={{Clade
}}}}
}}|2={{clade|1=Apusomonadida|label2=Opisthokonta|2={{clade|1=Holozoa|2=Holomycota}}}}}}}}}}}}
Taxonomy
= History =
The class Breviatea was created in 2004 by British protozoologist Thomas Cavalier-Smith to group a problematic taxon previously known as ‘Mastigamoeba invertens’. This organism, initially classified in the Archamoebae within phylum Amoebozoa, appeared to strongly diverge in phylogenetic trees based on ribosomal RNA and had a structure very different from other Archamoebae. Because of these results, ‘M. invertens’ was separated into the order Breviatida, contained in the monotypic class Breviatea. The organism was eventually renamed Breviata anathema. A family-level rank for these amoebae, Breviatidae, was formally described by the same author in 2013.
= Classification =
There are currently four accepted genera, each containing only one species.
- Breviata {{au|Walker, Dacks & Embley, 2006}}
- Breviata anathema {{au|Walker, Dacks & Embley, 2006}}
- Lenisia {{au|Hamann et al., 2016}}
- Lenisia limosa {{au|Hamann et al., 2016}}
- Pygsuia {{au|Brown et al., 2013}}
- Pygsuia biforma {{au|Brown et al., 2013}}
- Subulatomonas {{au|Katz et al., 2011}}
- Subulatomonas tetraspora {{au|Katz et al., 2011}}
References
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{{Life on Earth}}
{{Eukaryota}}
{{Taxonbar|from=Q21446474}}