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Centrohelid
The centrohelids or centroheliozoa are a large group of heliozoan protists. They include both mobile and sessile forms, found in freshwater and marine environments, especially at some depth. Characteristics Individuals are unicellular and spherical, usually around 30–80 μm in diameter, and covered with long radial axopods, narrow cellular projections that capture food and allow mobile forms to move about. A few genera have no cell covering, but most have a gelatinous coat holding scales and spines, produced in special deposition vesicles. These may be organic or siliceous and come in various shapes and sizes. For instance, in '' Raphidiophrys'' the coat extends along the bases of the axopods, covering them with curved spicules that give them a pine-treeish look, and in ''Raphidiocystis'' there are both short cup-shaped spicules and long tubular spicules that are only a little shorter than the axopods. Some other common genera include '' Heterophrys'', ''Actinocystis'', and ...
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Heterophrys
The centrohelids or centroheliozoa are a large group of heliozoan protists. They include both mobile and sessile forms, found in freshwater and marine environments, especially at some depth. Characteristics Individuals are unicellular and spherical, usually around 30–80 μm in diameter, and covered with long radial axopods, narrow cellular projections that capture food and allow mobile forms to move about. A few genera have no cell covering, but most have a gelatinous coat holding scales and spines, produced in special deposition vesicles. These may be organic or siliceous and come in various shapes and sizes. For instance, in '' Raphidiophrys'' the coat extends along the bases of the axopods, covering them with curved spicules that give them a pine-treeish look, and in ''Raphidiocystis'' there are both short cup-shaped spicules and long tubular spicules that are only a little shorter than the axopods. Some other common genera include '' Heterophrys'', ''Actinocystis'', and ...
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Raphidiophrys
Raphidiophrys is a genus of centrohelid with radiating axopodia.Zlatogursky, V. V. (2012). ''Raphidiophrys heterophryoidea'' sp. nov. (Centrohelida: Raphidiophryidae), the first heliozoan species with a combination of siliceous and organic skeletal elements. ''European Journal of Protistology, 48''(1), 9-16. doi:10.1016/j.ejop.2011.09.004 ''R. intermedia'' is found in the bottom sludge of freshwater bodies in Canada, Chile, Argentina, Australia, New Zealand, Malaysia, Russia, and central Europe. ''Raphidiophrys'' have bipartite scales are a defining characteristic among species. Differences in type and size of scales are used to differentiate amongst the members of this genus. The genus ''Raphidiophrys'' was discovered in 1867 by W. Archer. ''Raphidiophrys'' is one of very few centrohelids in which dimorphism has been shown. Habitat and Ecology ''Raphidiophrys'' can be found in freshwater habitats. Species can be found solitarily and/or colonially;Dürrschmidt, M., & Nicholls, ...
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Hacrobia
The cryptomonads-haptophytes assemblage is a proposed monophyletic grouping of unicellular eukaryotes that are not included in the SAR supergroup. Several alternative names have been used for the group, including Hacrobia (derived from "ha-" referring to Haptophyta, "-cr-" referring to cryptomonads, and "-bia" as a general suffix referring to life); CCTH (standing for Cryptophyta, Centrohelida, Telonemia and Haptophyta); and "Eukaryomonadae". , it is unclear whether this group is monophyletic or not; results of phylogenetic studies are "often dependent on the selection of taxa and gene data set". Two 2012 studies produced opposite results. Members In the past, heterokonts, haptophytes, and cryptomonads have sometimes been grouped together in a group known as chromists. Though the heterokonts are now split out, Cryptophyta and Haptophyta are considered in some studies to be closely related (and are sometimes simply referred to as the "Cryptophyta+Haptophyta" group). A 2009 pape ...
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Cryptomonads-haptophytes Assemblage
The cryptomonads-haptophytes assemblage is a proposed monophyletic grouping of unicellular eukaryotes that are not included in the SAR supergroup. Several alternative names have been used for the group, including Hacrobia (derived from "ha-" referring to Haptophyta, "-cr-" referring to cryptomonads, and "-bia" as a general suffix referring to life); CCTH (standing for Cryptophyta, Centrohelida, Telonemia and Haptophyta); and "Eukaryomonadae". , it is unclear whether this group is monophyletic or not; results of phylogenetic studies are "often dependent on the selection of taxa and gene data set". Two 2012 studies produced opposite results. Members In the past, heterokonts, haptophytes, and cryptomonads have sometimes been grouped together in a group known as chromists. Though the heterokonts are now split out, Cryptophyta and Haptophyta are considered in some studies to be closely related (and are sometimes simply referred to as the "Cryptophyta+Haptophyta" group). A 2009 pape ...
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Rhizaria
The Rhizaria are an ill-defined but species-rich supergroup of mostly unicellular eukaryotes. Except for the Chlorarachniophytes and three species in the genus Paulinella in the phylum Cercozoa, they are all non-photosynthethic, but many foraminifera and radiolaria have a symbiotic relationship with unicellular algae. A multicellular form, ''Guttulinopsis vulgaris'', a cellular slime mold, has also been described. This group was used by Cavalier-Smith in 2002, although the term "Rhizaria" had been long used for clades within the currently recognized taxon. Being described mainly from rDNA sequences, they vary considerably in form, having no clear morphological distinctive characters (synapomorphies), but for the most part they are amoeboids with filose, reticulose, or microtubule-supported pseudopods. In the absence of an apomorphy, the group is ill-defined, and its composition has been very fluid. Some Rhizaria possess mineral exoskeleton (thecae or loricas), which is in ...
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Haptista
Haptista is a proposed group of protists made up of centrohelids and haptophytes. Phylogenomic studies indicate that Haptista, together with ''Ancoracysta twista'', forms a sister clade to the SAR+Telonemia supergroup, but it may also be sister to the Cryptista (+Archaeplastida). It is thus one of the earliest diverging Diaphoretickes. Taxonomy Based on studies done by Cavalier-Smith, Chao & Lewis 2015 and Ruggiero et al. 2015. * Subphylum Centroheliozoa Cushman & Jarvis 1929 sensu Durrschmidt & Patterson 1987 eliozoa Haeckel 1862 stat. n. Margulis 1974 em. Cavalier-Smith 2003** Class Centrohelea Kuhn 1926 stat. n. Cavalier-Smith 1993 entroplastiales; Centrohelina Hartmann 1913; Centroplasthelida Febvre-Chevalier 1984* Subphylum Haptophytina Cavalier-Smith 2015 (Haptophyta The haptophytes, classified either as the Haptophyta, Haptophytina or Prymnesiophyta (named for '' Prymnesium''), are a clade of algae. The names Haptophyceae or Prymnesiophyceae are sometimes used i ...
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Oxnerella
''Oxnerella'' is a genus of centrohelid The centrohelids or centroheliozoa are a large group of heliozoan protists. They include both mobile and sessile forms, found in freshwater and marine environments, especially at some depth. Characteristics Individuals are unicellular and spher .... It includes the species ''Oxnerella maritima''. References {{Taxonbar, from=Q2912108 Hacrobia genera ...
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Heliozoa
Heliozoa, commonly known as sun-animalcules, are microbial eukaryotes ( protists) with stiff arms ( axopodia) radiating from their spherical bodies, which are responsible for their common name. The axopodia are microtubule-supported projections from the amoeboid cell body, and are variously used for capturing food, sensation, movement, and attachment. They are similar to Radiolaria, but they are distinguished from them by lacking central capsules and other complex skeletal elements, although some produce simple scales and spines. They may be found in both freshwater and marine environments. Classification Originally the heliozoa were treated together as a formal taxon Heliozoa or Heliozoea, with the rank of class or phylum, but it has been realised that they are polyphyletic, as the various orders show notable differences and are no longer believed to be descended from a single common ancestor. Instead, "heliozoa" is regarded as a descriptive term applying to various lines of pr ...
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Gymnosphaerid
The gymnosphaerids (or Gymnosphaerida) are a small group of heliozoan protists found in marine environments. They tend to be roughly spherical with radially directed axopods, supported by microtubules in a triangular-hexagonal array arising from an amorphous central granule. Genera There are only three genera, each with a single species: ''Gymnosphaera albida'', ''Hedraiophrys hovassei'', and ''Actinocoryne contractilis''. *''Gymnosphaera albida'' is free-living, usually benthic in shallow water. The cells are round and naked, around 70-100 μm in diameter, and resemble the unrelated '' Actinosphaerium''. The outer cytoplasm, or ectoplasm, forms a distinct layer containing large vesicles. *''Hedraiophrys hovassei'' is larger and lives attached to algae and other objects. The cells have a conical base, and are covered with long siliceous spicules. The ectoplasm is distinct and frothy, and typically contains bacterial and algal endosymbionts. *''Actinocoryne contractilis'' i ...
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Raphidiophryidae
Raphidiophryidae is a family of mostly freshwater centrohelids. It is the sister family of Acanthocystidae, sharing the trait of presenting silica scales and comprising the clade Chalarothoracina. Two genera, ''Raphidiophrys Raphidiophrys is a genus of centrohelid with radiating axopodia.Zlatogursky, V. V. (2012). ''Raphidiophrys heterophryoidea'' sp. nov. (Centrohelida: Raphidiophryidae), the first heliozoan species with a combination of siliceous and organic skelet ...'' and '' Polyplacocystis'', have been discovered so far. References {{Taxonbar, from=Q16989009 Haptista Eukaryote families ...
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Plants+HC Clade
Plants+HC clade is a group of eukaryotes proposed by Burki ''et al.'' (2008). It includes: * Plants * Hacrobia (the "HC" refers to Cryptophyta and Haptophyta, the two major members of this group) See also * photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in ... References Bikont unranked clades Diaphoretickes {{Bikont-stub ...
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