Discosea

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Discosea
Parasite140120-fig3 Acanthamoeba keratitis.png
Acanthamoeba sp.
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Phylum: Amoebozoa
Subphylum: Lobosa
Class: Discosea
Cavalier-Smith et al. 2004 [1]
Subclasses and orders [2]

Discosea is a class of Amoebozoa, consisting of naked amoebae with a flattened, discoid body shape. [1] Members of the group do not produce tubular or subcylindrical pseudopodia, like amoebae of the class Tubulinea. When a discosean is in motion, a transparent layer called hyaloplasm forms at the leading edge of the cell (see lamellipodium). In some discoseans, short "subpseudopodia" may be extended from this hyaloplasm, but the granular contents of the cell do not flow into these, as in true pseudopodia. Discosean amoebae lack hard shells, but some, like Cochliopodium and Korotnevella secrete intricate organic scales which may cover the upper (dorsal) surface of the cell. No species have flagella or flagellated stages of life. [3] [4]

Contents

The composition of Discosea is similar to that of the class Flabellinea, proposed by Alexey Smirnov and his collaborators in 2005. [5] However, Discosea is a more comprehensive taxon, including several groups not included in Flabellinea. [6] In 2011, Smirnov et al. accepted Discosea as a class, and reduced Flabellinea to the rank of a subclass with the name Flabellinia. [3]

Taxonomy

Class Discosea Cavalier-Smith 2004 stat. nov. Adl et al. 2018 [7]

Related Research Articles

<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, variously named Unikonta, Amorphea or Opimoda.

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

Lobosa is a taxonomic group of amoebae in the phylum Amoebozoa. Most lobosans possess broad, bluntly rounded pseudopods, although one genus in the group, the recently discovered Sapocribrum, has slender and threadlike (filose) pseudopodia. In current classification schemes, Lobosa is a subphylum, composed mainly of amoebae that have lobose pseudopods but lack cilia or flagella.

<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">Amoebidae</span> Family of protozoans

The Amoebidae are a family of Amoebozoa, including naked amoebae that produce multiple pseudopodia of indeterminate length. These are roughly cylindrical with granular endoplasm and no subpseudopodia, as found in other members of the class Tubulinea. During locomotion one pseudopod typically becomes dominant and the others are retracted as the body flows into it. In some cases the cell moves by "walking", with relatively permanent pseudopodia serving as limbs.

The Vannellidae are a family of Amoebozoa, which are found in soil, fresh- and salt water. The most common genus is Vannella.

<span class="mw-page-title-main">Tubulinea</span> Class of protozoans

The Tubulinea are a major grouping of Amoebozoa, including most of the more familiar amoebae genera like Amoeba, Arcella, Difflugia and Hartmannella.

<span class="mw-page-title-main">Eumycetozoa</span> Taxonomic group of slime molds

Eumycetozoa, or true slime molds, is a diverse group of protists that behave as slime molds and develop fruiting bodies, either as sorocarps or as sporocarps. It is a monophyletic group or clade within the phylum Amoebozoa that contains the myxogastrids, dictyostelids and protosporangiids.

<span class="mw-page-title-main">Leptomyxida</span> Order of protozoans

Leptomyxida is an order of Amoebozoa.

Dactylopodida is an Amoebozoa grouping.

Hartmannella is a genus of Amoebozoa.

Leptomyxa is a free-living genus of lobose naked multinucleate amoebae in the order Leptomyxida that inhabits freshwater, soil and mosses. It is very closely related to the genus Rhizamoeba, and some species have been moved between the two genera due to molecular data.

<i>Rhizamoeba</i> Genus of marine lobose amoebae

Rhizamoeba is a small genus of free-living marine naked lobose amoebae in the monotypic family Rhizamoebidae in the order Leptomyxida. It is most closely related to Leptomyxa and Flabellula, and some species have been moved to Leptomyxa due to molecular data.

<span class="mw-page-title-main">Testate amoebae</span> Group of amoebae with shells

Testate amoebae are a polyphyletic group of unicellular amoeboid protists, which differ from naked amoebae in the presence of a test that partially encloses the cell, with an aperture from which the pseudopodia emerge, that provides the amoeba with shelter from predators and environmental conditions.

<i>Trichosphaerium</i> Genus of amoebae

Trichosphaerium is a genus of amoebozoan protists that present extraordinary morphological transformations, both in size and shape, during their life cycle. They can present a test that may or may not be covered in spicules. They are related to the family Microcoryciidae, which contains other amoebae with tests, within the clade Corycidia of the phylum Amoebozoa.

<span class="mw-page-title-main">Flabellinia</span> Subclass of protozoans

The Flabellinia are a subclass of Amoebozoa. During locomotion the cells are flattened and have a clear layer called hyaloplasm along the front margin. Some form slender subpseudopodia projecting outward from the hyaloplasm, but the cell mass does not flow into these as in true pseudopodia, and advances without a definite central axis as in the Tubulinea. They also lack distinctive features like shells and flagella, and are united mainly by evidence from molecular trees.

<span class="mw-page-title-main">Cryptista</span> Clade of algae

Cryptista is a clade of alga-like eukaryotes. It is most likely related to Archaeplastida which includes plants and many algae, within the larger group Diaphoretickes.

Cutosea is a small group of marine amoeboid protists proposed in 2016. It is a monotypic class of Amoebozoa containing the order Squamocutida. Cutosean organisms are characterized by a cell coat of microscales separated from the cell membrane. Four genera, Armaparvus, Idionectes, Sapocribrum and Squamamoeba, belong to this group, distributed in three families.

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

Granofilosea is a class of cercozoan protists in the subphylum Reticulofilosa. Out of the three groups that were traditionally considered heliozoans: the heliomonads, gymnosphaerids and desmothoracids, the latter were recently grouped into this new class.

<span class="mw-page-title-main">Evosea</span> Group of amoebae

Evosea is a diverse clade of amoeboid protists discovered through molecular analyses. Along with Tubulinea and Discosea, Evosea is one of the three major groups within Amoebozoa, an important clade of eukaryotic organisms. It contains unicellular organisms that display a wide variety of life cycles and cell shapes, including amoebae, flagellates and different kinds of slime molds.

<span class="mw-page-title-main">Corycidia</span> Group of amoebae

Corycidia is a clade of amoeboid protists within the eukaryotic supergroup Amoebozoa. It contains all amoebae of the families Microcoryciidae, which was previously regarded as Arcellinida, and Trichosphaeriidae, which contains the sole genus Trichosphaerium.

References

  1. 1 2 Cavalier-Smith, Thomas; Chao, Ema E. -Y.; Oates, Brian (2004-05-18). "Molecular phylogeny of Amoebozoa and the evolutionary significance of the unikont Phalansterium". European Journal of Protistology. 40 (1): 21–48. doi:10.1016/j.ejop.2003.10.001.
  2. Kang S, Tice AK, Spiegel FW, Silberman JD, Pánek T, Cepicka I, et al. (September 2017). "Between a Pod and a Hard Test: The Deep Evolution of Amoebae". Molecular Biology and Evolution. 34 (9): 2258–2270. doi:10.1093/molbev/msx162. PMC   5850466 . PMID   28505375.
  3. 1 2 Smirnov, Alexey V.; Chao, Ema; Nassonova, Elena S.; Cavalier-Smith, Thomas (2011-10-01). "A revised classification of naked lobose amoebae (Amoebozoa: lobosa)". Protist. 162 (4): 545–570. doi:10.1016/j.protis.2011.04.004. ISSN   1618-0941. PMID   21798804.
  4. Adl, Sina M.; Simpson, Alastair G. B.; Lane, Christopher E.; Lukeš, Julius; Bass, David; Bowser, Samuel S.; Brown, Matthew W.; Burki, Fabien; Dunthorn, Micah (2012-09-01). "The revised classification of eukaryotes". The Journal of Eukaryotic Microbiology. 59 (5): 429–493. doi:10.1111/j.1550-7408.2012.00644.x. ISSN   1550-7408. PMC   3483872 . PMID   23020233.
  5. Smirnov, Alexey; Nassonova, Elena; Berney, Cédric; Fahrni, José; Bolivar, Ignacio; Pawlowski, Jan (2005-08-01). "Molecular phylogeny and classification of the lobose amoebae". Protist. 156 (2): 129–142. doi:10.1016/j.protis.2005.06.002. ISSN   1434-4610. PMID   16171181.
  6. "Catalogue of Organisms: Discosea: Keeping a Low Profile". coo.fieldofscience.com. Retrieved 2016-05-03.
  7. Adl, Sina M.; Bass, David; Lane, Christopher E.; Lukeš, Julius; Schoch, Conrad L.; Smirnov, Alexey; Agatha, Sabine; Berney, Cedric; Brown, Matthew W. (2018-09-26). "Revisions to the Classification, Nomenclature, and Diversity of Eukaryotes". Journal of Eukaryotic Microbiology. 66 (1): 4–119. doi:10.1111/jeu.12691. PMC   6492006 . PMID   30257078.

Discosea at Ferry Siemensma's Microworld Archived 2018-03-31 at the Wayback Machine

The order Hismatismenida at Penard.com