Jump to content

Ecdysozoa

From Wikipedia, the free encyclopedia

Ecdysozoa
Temporal range:Cambrian - RecentPossible traces age 556 Ma[1]
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Subkingdom: Eumetazoa
Clade: ParaHoxozoa
Clade: Bilateria
Clade: Nephrozoa
(unranked): Protostomia
Superphylum: Ecdysozoa
Aguinaldoet al., 1997
Phyla

Ecdysozoa(/ˌɛkdɪsoʊˈzoʊə/) is a group ofprotostomeanimals,[4]includingArthropoda(insects,chelicerata(includingarachnids),crustaceans,andmyriapods),Nematoda,and several smallerphyla.The grouping of theseanimalphyla into a singlecladewas first proposed by Eernisseet al.(1992) based on aphylogenetic analysisof 141 morphological characters of ultrastructural andembryologicalphenotypes.[5]This clade, that is, a group consisting of acommon ancestorand all its descendants, was formally named by Aguinaldoet al.in 1997, based mainly onphylogenetic treesconstructed using18S ribosomal RNAgenes.[6]

A large study in 2008 by Dunnet al.strongly supported themonophylyof Ecdysozoa.[7]

The group Ecdysozoa is supported by manymorphologicalcharacters, including growth byecdysis,with moulting of thecuticle– withoutmitosisin theepidermis– under control of theprohormoneecdysone,andinternal fertilization.[8]

The group was initially contested by a significant minority ofbiologists.Some argued for groupings based on more traditional taxonomic techniques,[9]while others contested the interpretation of themolecular data.[10][11]

Etymology

[edit]

The nameEcdysozoaisscientific Greek,derived fromἔκδυσις(ékdusis)"shedding"+ζῷον(zôion)"animal".

Characteristics

[edit]
See also:List of bilaterial animal orders

The most notable characteristic shared by ecdysozoans is a three-layeredcuticle(four inTardigrada[12]) composed of organic material, which is periodically molted as the animal grows. This process of molting is calledecdysis,and gives the group its name. The ecdysozoans lack locomotoryciliaand produce mostlyamoeboidsperm, and theirembryosdo not undergospiral cleavageas in most other protostomes. Ancestrally, the group exhibited sclerotized teeth within the foregut, and a ring of spines around the mouth opening, though these features have been secondarily lost in certain groups.[13][14]A respiratory and circulatory system is only present inonychophoransand arthropods (often absent in smaller arthropods like mites); in the rest of the groups, both systems are missing.

Phylogeny

[edit]

The Ecdysozoa include the following phyla:Arthropoda,Onychophora,Tardigrada,Kinorhyncha,Priapulida,Loricifera,Nematoda,andNematomorpha.A few other groups, such as thegastrotrichs,have been considered possible members but lack the main characters of the group, and are now placed elsewhere. The Arthropoda, Onychophora, and Tardigrada have been grouped together as thePanarthropodabecause they are distinguished by segmented body plans.[15]Dunnet al.in 2008 suggested that the tardigrada could be grouped along with the nematodes, leaving Onychophora as the sister group to the arthropods.[7]The non-panarthropod members of Ecdysozoa have been grouped asCycloneuraliabut they are more usually consideredparaphyleticin representing the primitive condition from which the Panarthropoda evolved.[16]

A modern consensusphylogenetic treefor the protostomes is shown below.[17][18][19][20][21][22]It is indicated when approximately clades radiated into newer clades in millions of years ago (Mya); dashed lines show especially uncertain placements.[23]

The phylogenetic tree is based on Nielsenet al.[24]and Howardet al.[25]

Bilateria

Older alternative groupings

[edit]

Articulata hypothesis

[edit]

The grouping proposed by Aguinaldoet al.is almost universally accepted, replacing an older hypothesis thatPanarthropodashould be classified withAnnelidain a group called theArticulata,and that Ecdysozoa arepolyphyletic.Nielsen has suggested that a possible solution is to regard Ecdysozoa as a sister-group ofAnnelida,[26]though later considered them unrelated.[27] Inclusion of theroundwormswithin the Ecdysozoa was initially contested[10][28][29]but since 2003, a broad consensus has formed supporting the Ecdysozoa[30]and in 2011 theDarwin–Wallace Medalwas awarded toJames Lakefor the discovery of the New Animal Phylogeny consisting of the Ecdysozoa, theLophotrochozoa,and the Deuterostomia.[31]

Coelomata hypothesis

[edit]

Before Aguinaldo's Ecdysozoa proposal, one of the prevailing theories for the evolution of thebilateral animalswas based on the morphology of theirbody cavities.There were three types, orgradesof organization: theAcoelomata(nocoelom), thePseudocoelomata(partial coelom), and theEucoelomata(truecoelom). Adoutte and coworkers were among the first to strongly support the Ecdysozoa.[32]With the introduction of molecular phylogenetics, the coelomate hypothesis was abandoned, although some molecular, phylogenetic support for the Coelomata continued until as late as 2005.[33]

References

[edit]
  1. ^abHoward RJ, Giacomelli M, Lozano-Fernandez J, Edgecombe GD, Fleming JF, Kristensen RM, et al. (2022)."The Ediacaran origin of ecdysozoa: Integrating fossil and phylogenomic data".Journal of the Geological Society.179(4).Bibcode:2022JGSoc.179..107H.doi:10.1144/jgs2021-107.hdl:2445/186596.S2CID246494357.Retrieved2023-07-30.
  2. ^Liu, Yunhuan; Carlisle, Emily; Zhang, Huaqiao; Yang, Ben; Steiner, Michael; Shao, Tiequan; et al. (17 August 2022)."Saccorhytus is an early ecdysozoan, and not the earliest deuterostome".Nature.609(7927): 541–546.Bibcode:2022Natur.609..541L.doi:10.1038/s41586-022-05107-z.hdl:1983/454e7bec-4cd4-4121-933e-abeab69e96c1.ISSN1476-4687.PMID35978194.S2CID251646316.
  3. ^Howard, Richard J.; Edgecombe, Gregory D.; Shi, Xiaomei; Hou, Xianguang; Ma, Xiaoya (23 November 2020)."Ancestral morphology of Ecdysozoa constrained by an early Cambrian stem group ecdysozoan".BMC Evolutionary Biology.20(1): 156.Bibcode:2020BMCEE..20..156H.doi:10.1186/s12862-020-01720-6.ISSN1471-2148.PMC7684930.PMID33228518.
  4. ^Telford, Maximilian J.; Bourlat, Sarah J.; Economou, Andrew; Papillon, Daniel; Rota-Stabelli, Omar (2008)."The evolution of the Ecdysozoa".Philosophical Transactions of the Royal Society B: Biological Sciences.363(1496): 1529–1537.doi:10.1098/rstb.2007.2243.ISSN0962-8436.PMC2614232.PMID18192181.
  5. ^Eernisse, D.J.; Albert, J.S.; Anderson, F.E. (1992). "Annelida and Arthropoda are not sister taxa: A phylogenetic analysis of spiralian metazoan morphology".Systematic Biology.41(3): 305–330.doi:10.1093/sysbio/41.3.305.
  6. ^Aguinaldo, A.M.A.; Turbeville, J.M.; Linford, L.S.; Rivera, M.C.; Garey, J.R.; Raff, R.A.; Lake, J.A. (29 May 1997). "Evidence for a clade of nematodes, arthropods, and other moulting animals".Nature.387(6632): 489–493.Bibcode:1997Natur.387R.489A.doi:10.1038/387489a0.PMID9168109.S2CID4334033.
  7. ^abDunn, C.W.; Hejnol, A.; Matus, D.Q.; Pang, K.; Browne, W.E.; Smith, S.A.; et al. (10 April 2008). "Broad phylogenomic sampling improves resolution of the animal tree of life".Nature.452(7188): 745–749.Bibcode:2008Natur.452..745D.doi:10.1038/nature06614.PMID18322464.S2CID4397099.
  8. ^Ax, P. (1985). "The position of the Gnathostomulida and Platyhelminthes in the phylogenetic system of the Bilateria". In Conway Morris, S.; George, J.D.; Gibson, R.; Platt, H.M. (eds.).The Origins and Relationships of Lower Invertebrates.Systematics Association Special Volume. Vol. 28. New York, NY: Clarendon / Oxford University Press. pp. 168–180.ISBN019857181X.OCLC59186778– via Internet Archive (archive.org).proceedings of an international symposium held in London, September 1983ISBN9780198571810
  9. ^Nielsen, Claus (1995).Animal Evolution: Interrelationships of the living phyla.Oxford University Press.ISBN978-0-19-850682-9.
  10. ^abBlair, J.E.; Ikeo, Kazuho; Gojobori, Takashi; Hedges, S. Blair (8 April 2002)."The evolutionary position of nematodes".BMC Evolutionary Biology.2:7.doi:10.1186/1471-2148-2-7.PMC102755.PMID11985779.
  11. ^Wägele, J.W.; Erikson, T.; Lockhart, P.; Misof, B. (December 1999)."The Ecdysozoa: Artifact or monophylum?".Journal of Zoological Systematics and Evolutionary Research.37(4): 211–223.doi:10.1111/j.1439-0469.1999.tb00985.x.
  12. ^Barnes, Robert D. (1982).Invertebrate Zoology.Philadelphia, PA: Holt-Saunders International. pp. 877–880.ISBN0-03-056747-5.
  13. ^Smith, Martin R.; Caron, Jean-Bernard (2 July 2015)."Hallucigenia's head and the pharyngeal armature of early ecdysozoans"(PDF).Nature.523(7558): 75–78.Bibcode:2015Natur.523...75S.doi:10.1038/nature14573.PMID26106857.S2CID205244325.
  14. ^Vinther, Jakob; Porras, Luis; Young, Fletcher J.; Budd, Graham E.; Edgecombe, Gregory D. (2016)."The mouth apparatus of the Cambrian gilled lobopodianPambdelurion whittingtoni".Palaeontology.59(6): 841–849.Bibcode:2016Palgy..59..841V.doi:10.1111/pala.12256.hdl:1983/16da11f1-5231-4d6c-9968-69ddc5633a8a.
  15. ^"Panarthropoda".Paleos (palaeos.com).Invertebrates. Archived fromthe originalon 2007-02-07.Retrieved17 February2007.
  16. ^Webster, Bonnie L.; Copley, Richard R.; Jenner, Ronald A.; Mackenzie-Dodds, Jacqueline A.; Bourlat, Sarah J.; Rota-Stabelli, Omar; et al. (November 2006). "Mitogenomics and phylogenomics reveal priapulid worms as extant models of the ancestral Ecdysozoan".Evolution & Development.8(6): 502–510.doi:10.1111/j.1525-142X.2006.00123.x.PMID17073934.S2CID22823313.
  17. ^Edgecombe, Gregory D.; Giribet, Gonzalo; Dunn, Casey W.; Hejnol, Andreas; Kristensen, Reinhardt M.; Neves, Ricardo C.; et al. (June 2011)."Higher-level metazoan relationships: Recent progress and remaining questions".Organisms, Diversity & Evolution.11(2): 151–172.doi:10.1007/s13127-011-0044-4.S2CID32169826.
  18. ^Fröbius, Andreas C.; Funch, Peter (4 April 2017)."Rotiferan Hox genes give new insights into the evolution of metazoan bodyplans".Nature Communications.8(1): 9.Bibcode:2017NatCo...8....9F.doi:10.1038/s41467-017-00020-w.PMC5431905.PMID28377584.
  19. ^Smith, Martin R.; Ortega-Hernández, Javier (2014)."Hallucigenia's onychophoran-like claws and the case for Tactopoda"(PDF).Nature.514(7522): 363–366.Bibcode:2014Natur.514..363S.doi:10.1038/nature13576.PMID25132546.S2CID205239797.
  20. ^"Palaeos Metazoa: Ecdysozoa".palaeos.com.Retrieved2017-09-02.
  21. ^Yamasaki, Hiroshi; Fujimoto, Shinta; Miyazaki, Katsumi (June 2015)."Phylogenetic position of Loricifera inferred from nearly complete 18S and 28S rRNA gene sequences".Zoological Letters.1:18.doi:10.1186/s40851-015-0017-0.PMC4657359.PMID26605063.
  22. ^Nielsen, C. (2002).Animal Evolution: Interrelationships of the Living Phyla(2nd ed.). Oxford University Press.ISBN0-19-850682-1.
  23. ^Peterson, Kevin J.; Cotton, James A.; Gehling, James G.; Pisani, Davide (27 April 2008)."The Ediacaran emergence of bilaterians: Congruence between the genetic and the geological fossil records".Philosophical Transactions of the Royal Society of London B: Biological Sciences.363(1496): 1435–1443.doi:10.1098/rstb.2007.2233.PMC2614224.PMID18192191.
  24. ^Nielsen, Claus; Brunet, Thibaut; Arendt, Detlev (2018-08-22). "Evolution of the bilaterian mouth and anus".Nature Ecology & Evolution.2(9): 1358–1376.Bibcode:2018NatEE...2.1358N.doi:10.1038/s41559-018-0641-0.ISSN2397-334X.PMID30135501.S2CID52067372.
  25. ^Howard, Richard J.; Giacomelli, Mattia; Lozano-Fernandez, Jesus; Edgecombe, Gregory D.; Fleming, James F.; Kristensen, Reinhardt M.; et al. (10 March 2022). "The Ediacaran origin of Ecdysozoa: Integrating fossil and phylogenomic data".Journal of the Geological Society.179(4).Bibcode:2022JGSoc.179..107H.doi:10.1144/jgs2021-107.hdl:2445/186596.ISSN0016-7649.S2CID246494357.
  26. ^Nielsen, C. (September 2003). "Proposing a solution to the Articulata–Ecdysozoa controversy".Zoologica Scripta.32(5): 475–482.doi:10.1046/j.1463-6409.2003.00122.x.S2CID1416582.
  27. ^Nielsen, Claus (2012).Animal Evolution: Interrelationships of the living phyla(3rd ed.). Oxford University Press.ISBN978-0-19-960603-0.
  28. ^Zrzavý, J. (12 January 2002)."Ecdysozoa versus Articulata: Clades, artifacts, prejudices".Journal of Zoological Systematics and Evolutionary Research.39(3): 159–163.doi:10.1046/j.1439-0469.2001.00168.x.— in support of clade Ecdysozoa
  29. ^Wägele, J.W.; Misof, B. (September 2001)."On quality of evidence in phylogeny reconstruction: A reply to Zrzavý's defence of the 'Ecdysozoa' hypothesis".Journal of Zoological Systematics and Evolutionary Research.39(3): 165–176.doi:10.1046/j.1439-0469.2001.00177.x.
  30. ^Telford, Maximilian J.; Littlewood, D. Timothy J. (27 April 2008)."The evolution of the animals: Introduction to a Linnean tercentenary celebration".Philosophical Transactions of the Royal Society B: Biological Sciences.363(1496): 1421–1424.doi:10.1098/rstb.2007.2231.PMC2394567.PMID18192193.
  31. ^"The Darwin-Wallace Medal"(Press release). The Linnean Society of London.Retrieved28 February2018.
  32. ^Adoutte, A.; Balavoine, G.; Lartillot, N.; Lespinet, O.; Prud'homme, B.; de Rosa, R. (25 April 2000)."The new animal phylogeny: Reliability and implications".Special feature.Proceedings of the National Academy of Sciences of the USA.97(9): 4453–4456.Bibcode:2000PNAS...97.4453A.doi:10.1073/pnas.97.9.4453.PMC34321.PMID10781043.
  33. ^Philip, G.K.; Creevey, C.J.; McInerney, J.O. (9 February 2005)."The Opisthokonta and the Ecdysozoa may not be clades: Stronger support for the grouping of plant and animal than for animal and fungi, and stronger support for the Coelomata than Ecdysozoa".Molecular Biology and Evolution.22(5): 1175–1184.doi:10.1093/molbev/msi102.PMID15703245.
[edit]
Wikispecieshas information related toEcdysozoa.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Ecdysozoa&oldid=1241771403"