| Corycidia | |
|---|---|
 | |
| Trichosphaerium sieboldi | |
Scientific classification  | |
| Domain: | Eukaryota |
| Phylum: | Amoebozoa |
| Class: | Tubulinea |
| Clade: | Corycidia Kang et al., 2017 [1] |
| Clades [1] | |
Corycidia (alternatively spelt Corycida) 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 (an order of testate amoebae), and Trichosphaeriidae, which contains the sole genus Trichosphaerium .
Corycidia is defined as the least inclusive clade containing Amphizonella , Diplochlamys and Trichosphaerium . It was discovered in 2017 through a phylogenomic study by Senghuo Kang and coauthors, published in the journal Molecular Biology and Evolution . [1] It is supported by independent analyses. [2] As of 2019, it is accepted by the International Society of Protistologists as part of the modern cladistic classification of eukaryotes, although under the alternative spelling Corycida. [3] The name Corycidia is derived from Latin corium 'leathery', referring to the "leathery" test that members of the clade have. [1]
Corycidia is located in the eukaryotic supergroup Amoebozoa, specifically inside the clade Tubulinea which unites most lobose amoebae (i.e. amoebae with blunt, thick pseudopodia). It is the most basal tubulinean lineage. The following cladogram depicts the phylogenetic position of Corycidia among other amoebozoan clades. [1] [2]
| Amoebozoa |
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A total of 7 genera are included within Corycidia, traditionally organized into two families: Trichosphaeriidae (one genus Trichosphaerium ), under the monotypic order Trichosida, and Microcoryciidae (six genera), previously assigned to the order Arcellinida. Only three genera are firmly placed in Corycidia through phylogenetic analyses: Amphizonella , Diplochlamys and Trichosphaerium . [1] The position of the genera Penardochlamys , Microcorycia , Zonomyxa and Parmulina , listed as part of the family Microcoryciidae, [4] is not clear. They have been tentatively placed in Corycidia due to a morphological resemblance, but it has not been demonstrated with molecular data. [3]
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.
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.
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.
Difflugia is the largest genus of Arcellinida, one of several groups of Tubulinea within the eukaryote supergroup Amoebozoa. Arcellinida species produce shells or tests from mineral particles or biogeonic elements and are thus commonly referred to as testate amoebae or shelled amoebae. Difflugia are particularly common in marshes and other freshwater habitats.
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).
Endomyxa is a group of eukaryotic organisms in the supergroup Rhizaria. They were initially a subphylum of Cercozoa and later a subphylum of Retaria, but several analyses have proven they are a phylogenetically separate lineage, and Endomyxa is currently regarded as its own phylum.
Thecofilosea is a class of unicellular testate amoebae belonging to the phylum Cercozoa. They are amoeboflagellates, organisms with flagella and pseudopodia, distinguished from other cercozoa by their scale-lacking test composed of organic material. They are closely related to the Imbricatea, a group of testate amoebae with tests composed of inorganic silica scales.
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.
Trichosphaerium is a genus of amoebozoan protists.
Apodera is a genus of amoeboid protists belonging to the family Hyalospheniidae, a group of shelled amoebae. Their shells, or tests, are lageniform with a clear constriction that separates the neck from the body.
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. Three genera, Armaparvus, Sapocribrum and Squamamoeba, belong to this group, distributed in two families.
Hyalospheniidae is a family of arcellinid testate amoebae and the sole family of the infraorder Hyalospheniformes. Commonly referred to as "hyalospheniids", these lobose amoebae are characterized by their ability to generate a shell composed of either organic matter or siliceous particles that may be recycled from euglyphid amoebae. They inhabit soil or freshwater habitats, and are abundant on Sphagnum mosses.
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.
Certesella is a genus of testate amoebae belonging to the family Hyalospheniidae. It is characterized by a test that presents two symmetrical holes near the opening, and by the presence of internal teeth within the test. It contains four species previously assigned to Nebela, as well as one species discovered in 2021.
Porosia is a genus of arcellinid testate amoebae belonging to the family Hyalospheniidae. Described in 1942, it used to be a monotypic genus with the sole species P. bigibbosa. However a second species, P. paracarinata, was discovered in 2015.
Cryptodifflugiidae is a family of arcellinid testate amoebae.
Pseudocucurbitella is a genus of freshwater testate amoebae of the order Arcellinida. Its shell is agglutinated, ovoid, with a round crossection and a circular aperture surrounded by 3 to 5 separate lobes forming a short collar.
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.
