Orthokaryotes

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Orthokaryotes
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Aulacantha , a Radiolarian
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Domain: Eukaryota
Clade: Orthokaryotes
Clades

The Orthokaryotes (Cavalier-Smith 2017) are a proposed Eukaryote clade consisting of the Jakobea and the Neokaryotes. [1] Together with its sister Discicristata it forms a basal Eukaryote clade. They are characterized by stacked Golgi, orthogonal centrioles, and two opposite posterior ciliary roots.

Taxonomy

A proposed cladogram is [2] [3] [4] [5] [6] [7] [8] [9] [1]

Eukaryota

Related Research Articles

<span class="mw-page-title-main">Chromista</span> Eukaryotic biological kingdom

Chromista is a proposed but polyphyletic biological kingdom, refined from the Chromalveolata, consisting of single-celled and multicellular eukaryotic species that share similar features in their photosynthetic organelles (plastids). It includes all eukaryotes whose plastids contain chlorophyll c and are surrounded by four membranes. If the ancestor already possessed chloroplasts derived by endosymbiosis from red algae, all non-photosynthetic Chromista have secondarily lost the ability to photosynthesise. Its members might have arisen independently as separate evolutionary groups from the last eukaryotic common ancestor.

<span class="mw-page-title-main">Thomas Cavalier-Smith</span> British evolutionary biologist (1942–2021)

Thomas (Tom) Cavalier-Smith, FRS, FRSC, NERC Professorial Fellow, was a professor of evolutionary biology in the Department of Zoology, at the University of Oxford.

<span class="mw-page-title-main">Amoebozoa</span> Phylum of protozoans

Amoebozoa is a major taxonomic group containing about 2,400 described species of amoeboid protists, often possessing blunt, fingerlike, lobose pseudopods and tubular mitochondrial cristae. In traditional classification schemes, Amoebozoa is usually ranked as a phylum within either the kingdom Protista or the kingdom Protozoa. In the classification favored by the International Society of Protistologists, it is retained as an unranked "supergroup" within Eukaryota. Molecular genetic analysis supports Amoebozoa as a monophyletic clade. Modern studies of eukaryotic phylogenetic trees identify it as the sister group to Opisthokonta, another major clade which contains both fungi and animals as well as several other clades comprising some 300 species of unicellular eukaryotes. Amoebozoa and Opisthokonta are sometimes grouped together in a high-level taxon, named Amorphea. Amoebozoa includes many of the best-known amoeboid organisms, such as Chaos, Entamoeba, Pelomyxa and the genus Amoeba itself. Species of Amoebozoa may be either shelled (testate) or naked, and cells may possess flagella. Free-living species are common in both salt and freshwater as well as soil, moss and leaf litter. Some live as parasites or symbionts of other organisms, and some are known to cause disease in humans and other organisms.

<span class="mw-page-title-main">Amorphea</span> Group including fungi, animals and various protozoa

Amorphea is a taxonomic supergroup that includes the basal Amoebozoa and Obazoa. That latter contains the Opisthokonta, which includes the Fungi, Animals and the Choanomonada, or Choanoflagellates. The taxonomic affinities of the members of this clade were originally described and proposed by Thomas Cavalier-Smith in 2002.

<span class="mw-page-title-main">Bikont</span> Group of eukaryotes

A bikont is any of the eukaryotic organisms classified in the group Bikonta. Many single-celled and multi-celled organisms are members of the group, and these, as well as the presumed ancestor, have two flagella.

<span class="mw-page-title-main">Cercomonad</span> Order of single-celled organisms

Cercomonads are small amoeboflagellates, widespread in aqueous habitats and common in soils.

<span class="mw-page-title-main">Apusozoa</span> Phylum of micro-organisms

The Apusozoa are a paraphyletic phylum 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.

<span class="mw-page-title-main">Corticata</span> Type of plant

Corticata, in the classification of eukaryotes, is a group suggested by Thomas Cavalier-Smith to encompass the eukaryote supergroups of the following two groups:

<span class="mw-page-title-main">Loukozoa</span> Proposed taxon

Loukozoa is a proposed taxon used in some classifications of eukaryotes, consisting of the Metamonada and Malawimonadea. Ancyromonads are closely related to this group, as sister of the entire group, or as sister of the Metamonada. Amorphea may have emerged in this grouping, specifically as sister of the Malawimonads.

<span class="mw-page-title-main">Diaphoretickes</span> Taxon of eukaryotes

Diaphoretickes is a major group of eukaryotic organisms, with over 400,000 species. The majority of the earth's biomass that carries out photosynthesis belongs to Diaphoretickes.

<span class="mw-page-title-main">Halvaria</span> Infrakingdom of protists

Halvaria is a taxonomic grouping of protists that includes Alveolata and Stramenopiles (Heterokonta).

<span class="mw-page-title-main">Podiata</span> Clade of shelled animals

Podiates are a proposed clade containing the Amorphea and the organisms now assigned to the clade CRuMs. Ancyromonadida does not appear to have emerged in this grouping. Sarcomastigota is a proposed subkingdom that includes all the podiates that are not animals or fungi. Sulcozoa is a proposed phylum within Sarcomastigota that does not include the phyla Amoebozoa (clade) and Choanozoa (paraphyletic), i.e. it includes the proposed subphyla Apusozoa and Varisulca

The initial version of a classification system of life by British zoologist Thomas Cavalier-Smith appeared in 1978. This initial system continued to be modified in subsequent versions that were published until he died in 2021. As with classifications of others, such as Carl Linnaeus, Ernst Haeckel, Robert Whittaker, and Carl Woese, Cavalier-Smith's classification attempts to incorporate the latest developments in taxonomy., Cavalier-Smith used his classifications to convey his opinions about the evolutionary relationships among various organisms, principally microbial. His classifications complemented his ideas communicated in scientific publications, talks, and diagrams. Different iterations might have a wider or narrow scope, include different groupings, provide greater or lesser detail, and place groups in different arrangements as his thinking changed. His classifications has been a major influence in the modern taxonomy, particularly of protists.

<span class="mw-page-title-main">Varisulca</span> Proposed phylum of protists

Varisulca was a proposed basal Podiate taxon. It encompassed several lineages of heterotrophic protists, most notably the ancyromonads (planomonads), collodictyonids (diphylleids), rigifilids and mantamonadids. Recent evidence suggests that the latter three are closely related to each other, forming a clade called CRuMs, but that this is unlikely to be specifically related to ancyromonads.

<span class="mw-page-title-main">Obazoa</span> Proposed group of single-celled organisms

Obazoa is a proposed sister clade of Amoebozoa. The term Obazoa is based on the OBA acronym for Opisthokonta, Breviatea, and Apusomonadidae, the group's three constituent clades.

<span class="mw-page-title-main">Neokaryotes</span> Eukaryote clade consisting of most protists

The neokaryotes are a proposed eukaryote clade consisting of the unikonts and the bikonts as sister of for instance the Jakobea. It arises because the Euglenozoa, Percolozoa, Tsukubea, and Jakobea are seen in this view as more basal eukaryotes. These four groups, are traditionally grouped together in the Discoba. However, the Discoba may well be paraphyletic as the neokaryotes may have emerged in them.

The Scotokaryotes (Cavalier-Smith) is a proposed basal Neokaryote clade as sister of the Diaphoretickes. Basal Scotokaryote groupings are the Metamonads, the Malawimonas and the Podiata. In this phylogeny the Discoba are sometimes seen as paraphyletic and basal Eukaryotes.

Mantamonads are a group of free-living heterotrophic flagellates that move primarily by gliding on surfaces. They are classified as one genus Mantamonas in the monotypic family Mantamonadidae, order Mantamonadida and class Glissodiscea. Previously, they were classified in Apusozoa as sister of the Apusomonadida on the basis of rRNA analyses. However, mantamonads are currently placed in CRuMs on the basis of phylogenomic analyses that identify their closest relatives as the Diphylleida and Rigifilida.

<span class="mw-page-title-main">Cortical alveolum</span> Cellular organelle found in protists

The cortical alveolum is a cellular organelle consisting of a vesicle located under the cytoplasmic membrane, to which they give support. The term "corticate" comes from an evolutionary hypothesis about the common origin of kingdoms Plantae and Chromista, because both kingdoms have cortical alveoli in at least one phylum. At least three protist lineages exhibit these structures: Telonemia, Alveolata and Glaucophyta.

Eolouka is a paraphyletic phylum of protists localized in the clade Discoba. It contains two lineages: Jakobea and Tsukubea, the last containing only one genus, Tsukubamonas.

References

  1. 1 2 Cavalier-Smith, Thomas (5 September 2017). "Kingdom Chromista and its eight phyla: a new synthesis emphasising periplastid protein targeting, cytoskeletal and periplastid evolution, and ancient divergences". Protoplasma. 255 (1): 297–357. doi:10.1007/s00709-017-1147-3. ISSN   0033-183X. PMC   5756292 . PMID   28875267.
  2. Zaremba-Niedzwiedzka, Katarzyna; Caceres, Eva F.; Saw, Jimmy H.; Bäckström, Disa; Juzokaite, Lina; Vancaester, Emmelien; Seitz, Kiley W.; Anantharaman, Karthik; Starnawski, Piotr (11 January 2017). "Asgard archaea illuminate the origin of eukaryotic cellular complexity" (PDF). Nature. advance online publication (7637): 353–358. Bibcode:2017Natur.541..353Z. doi:10.1038/nature21031. ISSN   1476-4687. OSTI   1580084. PMID   28077874. S2CID   4458094.
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  5. Cavalier-Smith, Thomas (23 June 2010). "Kingdoms Protozoa and Chromista and the eozoan root of the eukaryotic tree". Biology Letters. 6 (3): 342–345. doi:10.1098/rsbl.2009.0948. ISSN   1744-9561. PMC   2880060 . PMID   20031978.
  6. He, Ding; Fiz-Palacios, Omar; Fu, Cheng-Jie; Fehling, Johanna; Tsai, Chun-Chieh; Baldauf, Sandra L. (2014). "An Alternative Root for the Eukaryote Tree of Life". Current Biology. 24 (4): 465–470. Bibcode:2014CBio...24..465H. doi: 10.1016/j.cub.2014.01.036 . PMID   24508168.
  7. Cavelier Smith (2013). "Early evolution of eukaryote feeding modes, cell structural diversity, and classification of the protozoan phyla Loukozoa, Sulcozoa, and Choanozoa". European Journal of Protistology. 49 (2): 115–178. doi:10.1016/j.ejop.2012.06.001. PMID   23085100.
  8. Hug, Laura A.; Baker, Brett J.; Anantharaman, Karthik; Brown, Christopher T.; Probst, Alexander J.; Castelle, Cindy J.; Butterfield, Cristina N.; Hernsdorf, Alex W.; Amano, Yuki (11 April 2016). "A new view of the tree of life". Nature Microbiology. 1 (5): 16048. doi: 10.1038/nmicrobiol.2016.48 . ISSN   2058-5276. PMID   27572647.
  9. Cavalier-Smith, Thomas; Chao, Ema E.; Lewis, Rhodri (1 June 2016). "187-gene phylogeny of protozoan phylum Amoebozoa reveals a new class (Cutosea) of deep-branching, ultrastructurally unique, enveloped marine Lobosa and clarifies amoeba evolution". Molecular Phylogenetics and Evolution. 99: 275–296. Bibcode:2016MolPE..99..275C. doi: 10.1016/j.ympev.2016.03.023 . PMID   27001604.