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.[1][2][3] 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.[4] They may be found in both freshwater and marine environments.
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 protists.
Several nucleariids were once considered heliozoa, but they do not have microtubule-supported axopods and so are now considered filose amoeboids instead.
Phylogenyedit
The heliozoa are a polyphyletic grouping of various protists that have independently evolved axopodial arms. Some of the heliozoan groups are intermingled in the supergroup Rhizaria with radiolarians, their mostly marine counterpart.[5]
^D.J. Patterson (1996). Free-living freshwater Protozoa. ASM Press. p. 168.
^Cavalier-Smith, Thomas (December 1993). "Kingdom Protozoa and its 18 phyla". Microbiological Reviews. 57 (4): 953–994. doi:10.1128/mmbr.57.4.953-994.1993. PMC372943. PMID 8302218.
^ abNikolaev SI, Berney C, Fahrni JF, et al. (May 2004). "The twilight of Heliozoa and rise of Rhizaria, an emerging supergroup of amoeboid eukaryotes". Proc. Natl. Acad. Sci. U.S.A. 101 (21): 8066–71. doi:10.1073/pnas.0308602101. PMC419558. PMID 15148395.
^Cavalier-Smith, Thomas; Chao, Ema E. (2012). "Oxnerella micra sp. n. (Oxnerellidae fam. n.), a Tiny Naked Centrohelid, and the Diversity and Evolution of Heliozoa". Protist. 163 (4): 574–601. doi:10.1016/j.protis.2011.12.005. PMID 22317961.
heliozoa, commonly, known, animalcules, microbial, eukaryotes, protists, with, stiff, arms, axopodia, radiating, from, their, spherical, bodies, which, responsible, their, common, name, axopodia, microtubule, supported, projections, from, amoeboid, cell, body,. 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 1 2 3 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 4 They may be found in both freshwater and marine environments Sun animalculesHeliozoan depicted by Louis Joblot 1718Scientific classification obsolete Domain EukaryotaPhylum SarcodinaClass Actinopoda fr Order HeliozoaHaeckel 1866 Contents 1 Classification 1 1 Phylogeny 2 References 3 External linksClassification editOriginally 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 protists The primary groups include 5 Actinophryida Pedinellida and Ciliophryida currently in Stramenopiles Centrohelida some support for Hacrobia Desmothoracida Heliomonadida Dimorphida and Gymnosphaerida currently in Rhizaria gt Cercozoa Taxopodida Sticholonche currently in Rhizaria gt Radiolaria Rotosphaerida currently in Opisthokonta gt Nucleariida and in Rhizaria 6 Several nucleariids were once considered heliozoa but they do not have microtubule supported axopods and so are now considered filose amoeboids instead Phylogeny edit The heliozoa are a polyphyletic grouping of various protists that have independently evolved axopodial arms Some of the heliozoan groups are intermingled in the supergroup Rhizaria with radiolarians their mostly marine counterpart 5 Eukaryotes Diaphoretickes SAR Stramenopiles Raphidomonadea Actinophryida nbsp Dictyochophyceae Pedinellales nbsp Rhizaria Cercozoa Thecofilosea Phaeodaria nbsp classical radiolarians Granofilosea Desmothoracida nbsp GymnosphaeridaRadiolaria Acantharea nbsp classical radiolarians TaxopodidaPolycystinea nbsp classical radiolarians Haptista Centroplasthelida nbsp Cryptista EndoheleaPlantsOpisthokonta Nucleariida nbsp References edit Cavalier Smith T von der Heyden S September 2007 Molecular phylogeny scale evolution and taxonomy of centrohelid heliozoa Mol Phylogenet Evol 44 3 1186 203 doi 10 1016 j ympev 2007 04 019 PMID 17588778 Sarcodia Retrieved 28 August 2014 D J Patterson 1996 Free living freshwater Protozoa ASM Press p 168 Cavalier Smith Thomas December 1993 Kingdom Protozoa and its 18 phyla Microbiological Reviews 57 4 953 994 doi 10 1128 mmbr 57 4 953 994 1993 PMC 372943 PMID 8302218 a b Nikolaev SI Berney C Fahrni JF et al May 2004 The twilight of Heliozoa and rise of Rhizaria an emerging supergroup of amoeboid eukaryotes Proc Natl Acad Sci U S A 101 21 8066 71 doi 10 1073 pnas 0308602101 PMC 419558 PMID 15148395 Cavalier Smith Thomas Chao Ema E 2012 Oxnerella micra sp n Oxnerellidae fam n a Tiny Naked Centrohelid and the Diversity and Evolution of Heliozoa Protist 163 4 574 601 doi 10 1016 j protis 2011 12 005 PMID 22317961 External links edit nbsp Wikispecies has information related to Heliozoa Actinosphaerium single celled is an example of a heliozoa For an image see http www microscopy uk org uk index html http www microscopy uk org uk ponddip Heliozoa Encyclopaedia Britannica 11th ed 1911 nbsp This Eukaryote related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Heliozoa amp oldid 1184773521, wikipedia, wiki, book, books, library,
