Desmothoracid
Desmothoracids
Scientific classification
Domain: Eukaryota
Kingdom: Rhizaria
Phylum: Cercozoa[1]
Class: Proteomyxidea?
Order: Desmothoracida
Hertwig & Lesser, 1874
Family: Clathrulinidae
Claus, 1874
Genera

Clathrulina
Hedriocystis
Cienkowskya
Penardiophrys
Actinosphaeridium

The desmothoracids are a group of heliozoan protists, usually sessile and found in freshwater environments. Each adult is a spherical cell around 10-20 μm in diameter surrounded by a perforated organic lorica or shell, with many radial pseudopods projecting through the holes to capture food. These are supported by small bundles of microtubules that arise near a point on the nuclear membrane. Unlike other heliozoans, the microtubules are not in any regular geometric array, there does not appear to be a microtubule organizing center, and there is no distinction between the outer and inner cytoplasm.

Reproduction takes place by the budding off of small motile cells, usually with two flagella. Later these are lost, and pseudopods and a lorica are formed. Typically a single lengthened pseudopod will secrete a hollow stalk that attached the adult to the substrate. The form of the flagella, the tubular cristae within the mitochondria, and other characters led to the suggestion that the desmothoracids belong among what is now the Cercozoa, which has now been confirmed by genetic studies.

References

  1. ^ 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. http://www.pnas.org/cgi/pmidlookup?view=long&pmid=15148395. 
  • K.A. Mikrjukov (2000). "Taxonomy and Phylogeny of Heliozoa. I. Desmothoracids". Acta Protozoologica 39: 81–97. 
  • Nikolaev, S.I. et al. (2003). "Genetic Relationships between Desmothoracid Heliozoa and Gymnophryid Amoebas as Evidenced by Comparison of 18S rRNA Genes". Doklady Biological Sciences 393: 553–556. doi:10.1023/B:DOBS.0000010322.33294.9f. PMID 14994549. 

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  • Gymnosphaerid — Taxobox color = khaki name = Gymnosphaerids domain = Eukaryota unranked phylum = Rhizaria phylum = Cercozoa? classis = Proteomyxidea? ordo = Gymnosphaerida ordo authority = Poche, 1913 subdivision ranks = Species subdivision = Gymnosphaera elbida …   Wikipedia

  • Heliozoa — Heliozoa, or sun animalcules, are roughly spherical amoeboids with many stiff, microtubule supported projections called axopods radiating outward from the cell surface. These give them the characteristic sun like appearance for which they are… …   Wikipedia

  • Clathrulinidae — Systematik Klassifikation: Lebewesen Domäne: Eukaryoten (Eucaryota) ohne Rang: Rhizaria ohne Rang: Cercozoa …   Deutsch Wikipedia

  • Desmothoracida — Clathrulinidae Systematik Klassifikation: Lebewesen Domäne: Eukaryoten (Eucaryota) ohne Rang: Rhizaria ohne Rang: Ce …   Deutsch Wikipedia

  • Desmothoracida — Saltar a navegación, búsqueda ? Desmothoracida Clasificación científica Reino: Protista (sin clasif.) …   Wikipedia Español

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