Polychaos | |
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Genus: | Polychaos Schaeffer 1926 [1] |
Type species | |
Polychaos dubium (Schaeffer 1916) Schaeffer 1926 |
Polychaos is an amoeboid genus in the Amoebozoa group. [2] Several characters unite the species in this genus. The pseudopods meld at their bases when the organism is moving, and have dorsal, longitudinal ridges. The nucleus is oval or ellipsoidal. [3]
Polychaos includes the following species: [3]
Phylogenetic analysis has shown this that genus belongs to the family Hartmannellidae. [4]
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.
The euglyphids are a prominent group of filose amoebae that produce shells or tests that in most described species is reinforced by siliceous scales, plates, and sometimes spines, but this reinforcement is absent in other species. These elements are created within the cell and then assembled on its surface in a more or less regular arrangement, giving the test a textured appearance. There is a single opening for the long slender pseudopods, which capture food and pull the cell across the substrate.
The Vannellidae are a family of Amoebozoa, which are found in soil, fresh- and salt water. The most common genus is Vannella.
The Tubulinea are a major grouping of Amoebozoa, including most of the more familiar amoebae genera like Amoeba, Arcella, Difflugia and Hartmannella.
Discosea is a class of Amoebozoa, consisting of naked amoebae with a flattened, discoid body shape. 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. 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.
Arcellinid testate amoebae or Arcellinida, Arcellacean or lobose testate amoebae are single-celled protists partially enclosed in a simple test (shell).
Polychaos dubium is a freshwater amoeboid and one of the larger species of single-celled eukaryote. Like other amoebozoans, P. dubium moves by means of temporary projections called pseudopods. P. dubium reportedly has one of the largest genome size of any organism known, though the authors of a 2004 study suggest treating that measurement with caution.
Leptomyxida is an order of Amoebozoa.
Cochliopodium is a Himatismenida genus.
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.
Vannella is a genus of Amoebozoa.
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.
Mayorella is a genus of small amoeboid protists in the phylum Amoebozoa. The genus consists of amoebae that exhibit pseudopodia and feed on a variety of organisms through phagocytosis, making them an important group in microbial ecology across most environments worldwide. Mayorella species have been found in soil, freshwater and marine environments.
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.
Thecamoebais a genus of Amoebozoa with a tough pellicle simulating a shell.
Alfred G. Mayer was an American marine biologist and zoologist, whose fascination with medusae (jellyfish) marked a turning point for biology. Despite Mayor's interest in the sea, his first voyage began during his twenty-fourth year of life. Because of his German 'heritage', "[...]he altered it to "Mayor" in order to dissociate himself from his Germanic roots". Mayor is also greatly known for his many publications and papers in which he wrote about topics ranging from physics to hunting and fishing.
Nebela is a diverse genus of testate amoebae of cosmopolitan distribution, belonging to the family Hyalospheniidae. They are "prey agglutinated" or "kleptosquamic" organisms, meaning they take the inorganic plates from their prey to construct their test.
Cryptodifflugiidae is a family of arcellinid testate amoebae.
Planocarina is a genus of arcellinid testate amoebae belonging to the family Hyalospheniidae. It was created in 2016 to agglutinate a clade of species that were previously assigned to the paraphyletic genus Nebela. All species of Planocarina have a compressed keel surrounding the posterior part of their shell. It is the sister group of Alabasta.
Alabasta is a genus of arcellinid testate amoebae belonging to the family Hyalospheniidae. It contains species with an elongated test and a strongly curved "pseudostome" with a flare and a notch in narrow view. These species previously belonged to the genus Nebela, but were later found to be a distinct monophyletic group different from Nebela. It is the sister group to Planocarina.