Euglyphida

Euglyphida
"Euglypha" sp.
Euglypha sp.
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Phylum: Cercozoa
Class: Imbricatea
Order: Euglyphida
Copeland, 1956
Families[1]

The euglyphids are a prominent group of filose amoebae that produce shells or tests that in most described species is reinforced by siliceous scales, plates, and sometimes spines, but this reinforcement is absent in other species.[2]

These elements are created within the cell and then assembled on its surface in a more or less regular arrangement, giving the test a textured appearance. There is a single opening for the long slender pseudopods, which capture food and pull the cell across the substrate.

Euglyphids are common in soils, marshes, and other organic-rich environments, feeding on tiny organisms such as bacteria. The test is generally 30–100 μm in length, although the cell only occupies part of this space. During reproduction a second shell is formed opposite the opening, so both daughter cells remain protected. Different genera and species are distinguished primarily by the form of the test. Euglypha and Trinema are the most common.

The euglyphids are traditionally grouped with other amoebae. However, genetic studies instead place them with various amoeboid and flagellate groups, forming an assemblage called the Cercozoa. Their closest relatives are the thaumatomonads, flagellates that form similar siliceous tests.

Photosynthetic species are found in the genera Paulinella and Placocista. The photosynthetic abilities in Paulinella comes from an event when a cyanobacterium settled permanently within the cell. In Placocista, where a few species have colonies of symbiotic Chlorella living inside them, the relationship is less intimate. The photosynthetic Paulinella are phototrophic, and the photosynthetic Placocista are mixotrophic.[3][4][5]

Morphology

[edit]
Representation of a euglyphid
  1. Siliceous test plate
  2. Golgi apparatus; modifies proteins and sends them out of the cell
  3. Endoplasmic reticulum, the transport network for molecules going to specific parts of the cell
  4. Nucleus
  5. Nucleolus
  6. Spine
  7. Mitochondrion, creates ATP (energy) for the cell
  8. Matrix vesicle
  9. Matrix
  10. Reserve plate
  11. Pigment granule
  12. Bacterial endosymbiont
  13. Contractile vacuole, regulates the quantity of water inside a cell
  14. Lysosome, holds enzymes
  15. Phagocytic vacuoles with prey
  16. Digestive vacuole
  17. Large central vacuole
  18. Epipodium
  19. Apertural collar
  20. Retracting filopodium
  21. Extended filopodium

Phylogeny

[edit]

Phylogeny based on Chatelain et al. 2013[6]

Euglyphida

Paulinellidae de Saedeleer 1934 emend. Adl et al. 2012

Cyphoderiidae de Saedeleer 1934

Tracheleuglypha Deflandre 1928

Euglyphina

Assulinidae Lara et al. 2007

Euglyphidae Wallich 1864 emend Lara et al. 2007

Sphenoderiidae Chatelain et al. 2013

Trinematidae Hoogenraad & De Groot 1940 emend Adl et al. 2012

Taxonomy

[edit]

Order Euglyphida Copeland 1956 emend. Cavalier-Smith 1997[7]

References

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  1. ^ Euglyphida, WoRMS – World Register of Marine Species, retrieved 7 September 2018
  2. ^ Description of Phaeobola aeris gen. nov., sp. nov (Rhizaria, Cercozoa, Euglyphida) Sheds Light on Euglyphida’s Dark Matter - Digital CSIC
  3. ^ Grube, Martin; Seckbach, Joseph; Muggia, Lucia (29 December 2016). Algal and Cyanobacteria Symbioses. World Scientific. ISBN 978-1-78634-059-7.
  4. ^ Gomaa, F.; Kosakyan, A.; Heger, T. J.; Corsaro, D.; Mitchell, E. A.; Lara, E. (2014). "One Alga to Rule them All: Unrelated Mixotrophic Testate Amoebae (Amoebozoa, Rhizaria and Stramenopiles) Share the Same Symbiont (Trebouxiophyceae)". Protist. 165 (2): 161–176. doi:10.1016/j.protis.2014.01.002. PMID 24646792.
  5. ^ Gabr, A.; Grossman, A. R.; Bhattacharya, D. (2020). "Paulinella, A Model for Understanding Plastid Primary Endosymbiosis". Journal of Phycology. 56 (4): 837–843. Bibcode:2020JPcgy..56..837G. doi:10.1111/jpy.13003. PMC 7734844. PMID 32289879.
  6. ^ Chatelain, Auriel P.; Meisterfeld, Ralf; Roussel-Delif, Ludovic; Lara, Enrique (2013), "Sphenoderiidae (fam. nov.), a New Clade of Euglyphid Testate Amoebae Characterized by Small, Round Scales Surrounding the Aperture" (PDF), Protist, 164 (6): 782–792, doi:10.1016/j.protis.2013.08.001, PMID 24152919
  7. ^ Kosakyan, Anush; Gomaa, Fatma; Lara, Enrique; Lahr, Daniel J.G. (2016), "Current and future perspectives on the systematics, taxonomy and nomenclature of testate amoebae", European Journal of Protistology, 164 (6): 782–792, doi:10.1016/j.ejop.2016.02.001, hdl:11380/1302106, PMID 27004416