Arcellinida

Arcellinida
Scientific classification
Domain: Eukaryota
Kingdom: Amoebozoa
Phylum: Tubulinea
Order: Arcellinida

Arcellinid testate amoebae or Arcellinida,[1] Arcellacean[2] or lobose testate amoebae[3] are single-celled protists partially enclosed in a simple test (shell).

Arcellinid testate amoebae are commonly found in soils, leaf litter, peat bogs and near/in fresh water.[1] They use their pseudopodia (false feet), a temporary cell extension, for moving and taking in food. Like most amoebae, they are generally believed to reproduce asexually via binary fission. However a recent review suggests that sexual recombination may be the rule rather than the exception in amoeboid protists in general, including the Arcellinid testate amoebae.[4]

Test or shell

Simple tests (or shells) are made by either secretion (autogenous tests) or by the agglutination of foreign material (xenogenous tests), or sometimes a combination of both. Past environmental changes can be determined by analysing the composition of fossil tests, including the reconstruction of past climate change.[1]

Evolutionary history

Fossils of arcellinid testate amoebae date back to the Cryogenian period.[5]

Testate amoebae are theorized to be mostly polyphyletic (coming from more than one ancestral type), but testaceafilosea, one group of testate amoebae, are theorized to be made up of one ancestral type (monophyletic). Ancient tests of terrestrial fauna are commonly found in fossilized amber,[6] although an important new study has found mid-Cretaceous testate amoeba (i.e., Diffligia, Cucurbitella) in ancient lake sediments.[7] It is likely that the group has evolved minimally over the course of the Phanerozoic.

Classification

The group contains the following taxa (NB this list needs to be updated based on Adl et al. 2012),:[8][9]

incertae sedis:

References

  1. ↑ 1.0 1.1 1.2 http://www.microscopy-uk.org.uk/mag/artjun03/gsamoebae.html Testate amoebae, peat bogs and past climates. accessed 16 march 2007
  2. ↑ Identification key for holocene lacustrine arcellacean (thecamoebian) taxa
  3. ↑ Lara E, Heger TJ, Ekelund F, Lamentowicz M, Mitchell EA (April 2008). "Ribosomal RNA genes challenge the monophyly of the Hyalospheniidae (Amoebozoa: Arcellinida)". Protist 159 (2): 165–76. doi:10.1016/j.protis.2007.09.003. PMID 18023614.
  4. ↑ Lahr DJG, Parfrey LW, Mitchell EAD, Katz LA, Lara E (2011). "The chastity of amoebae: re-evaluating evidence for sex in amoeboid organisms". Proceedings of the Royal Society B-Biological Sciences 278: 2081–2090. doi:10.1098/rspb.2011.0289. PMC 3107637. PMID 21429931.
  5. ↑ Porter, S.A., and Knoll, A.H. (2000) Testate amoeba in the Neoproterozoic Era: evidence from vase-shaped microfossils in the Chuar Group, Grand Canyon: Paleobiology 26 (3): 360-385. Also see Cryogenian
  6. ↑ Schmidt, A.R.; Ragazzi, E.; Coppellotti, O.; Roghi, G. (2006). "A microworld in Triassic amber". Nature 444 (7121): 835. doi:10.1038/444835a. PMID 17167469.
  7. ↑ Hengstum, Van; Reinhardt, E.G.; Medioli, F.S.; Grocke, D.R. (2007). "Exceptionally preserved late albian (Cretaceous) Arcellaceans (Thecamoebians) from the Dakota Formation near Lincoln, Nebraska". Journal of Foraminiferal Research 37 (4): 300–308. doi:10.2113/gsjfr.37.4.300.
  8. ↑ Ralf Meisterfeld: Arcellinida, In: John J. Lee, Gordon F. Leedale, Phyllis Bradbury (Hrsg.): Illustrated Guide to the Protozoa, 2nd Edition. Vol. 2, Society of Protozoologists, Lawrence, Kansas 2000, ISBN 1-891276-23-9, pp. 827-860
  9. ↑ Adl SM, Simpson AGB, Lane CE, Lukeš J, Bass D, Bowser SS, Brown MW, Burki F, Dunthorn M, Hampl V, Heiss A, Hoppenrath M, Lara E, le Gall L, Lynn DH, McManus H, Mitchell EAD, Mozley-Stanridge SE, Parfrey LW, Pawlowski J, Rueckert S, Shadwick L, Schoch CL, Smirnov A, Spiegel FW (2012). "The Revised Classification of Eukaryotes". Journal of Eukaryotic Microbiology 59: 429–514. doi:10.1111/j.1550-7408.2012.00644.x. PMC 3483872. PMID 23020233.

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