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Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladi: Bilateria – Cnidaria (phylum)
Phyla (Cladus incertae sedis): Ctenophora – Monoblastozoa – †Trilobozoa
Genera incertae sedis: †Anulitubus
Overview of phyla (38 + 1†)

Acanthocephala – Acoela – Annelida – Arthropoda – Brachiopoda – Bryozoa – Chaetognatha – Chordata – Cnidaria – Ctenophora – Cycliophora – Dicyemida – Echinodermata – Echiura – Entoprocta – Gastrotricha – Gnathostomulida – Hemichordata – Kinorhyncha – Loricifera – Micrognathozoa – Mollusca – Monoblastozoa – Myxozoa – Myzostomida – Nematoda – Nematomorpha – Nemertea – Nemertodermatida – Onychophora – Orthonectida – Phoronida – Platyhelminthes – Priapulida – Rotifera – Sipuncula – Tardigrada – Xenoturbellida – †Trilobozoa

Eumetazoa Bütschli, 1910

Peterson, K.J. & Butterfield, N.J. 2005. Origin of the Eumetazoa: Testing ecological predictions of molecular clocks against the Proterozoic fossil record. PNAS 102: 9547–9552. DOI: 10.1073/pnas.0503660102 JSTOR
Sperling, E.A., Peterson, K.J. & Pisani, D. 2009. Phylogenetic-Signal Dissection of Nuclear Housekeeping Genes Supports the Paraphyly of Sponges and the Monophyly of Eumetazoa. Molecular biology and evolution 26: 2261–2274. DOI: 10.1093/molbev/msp148

Vernacular names
Alemannisch: Gwäbtierer
العربية: بعديات حقيقية
Boarisch: Geweeweviecher
беларуская: Эўметазоі
català: Eumetazous
čeština: Eumetazoa
Deutsch: Gewebetiere
Ελληνικά: Ευμετάζωα
English: Eumetazoans
español: Eumetazoos
eesti: Pärishulkraksed
suomi: Monisoluiset eläimet
Nordfriisk: Eumetazoa
français: Eumétazoaires
galego: Eumetazoos
עברית: רב תאיים אמיתיים
magyar: Valódi szövetes állatok
italiano: Eumetazoa
日本語: 真正後生動物亜界
한국어: 진정후생동물아계
lietuvių: Tikrieji daugialąsčiai
latviešu: Daudzšūnu dzīvnieki
македонски: Ткивни животни
Nederlands: Orgaandieren
norsk: Flercellede dyr
polski: Tkankowce właściwe
português: Eumetazoários
русский: Эуметазои
slovenščina: Prave živali
српски / srpski: Prave životinje
svenska: Flercelliga djur
Türkçe: Gerçek dokusu olan hayvanlar
українська: Справжні багатоклітинні
中文: 真後生動物亞界

Eumetazoa (from Ancient Greek εὖ (eû) 'well', μετά (metá) 'after', and ζῷον (zôion) 'animal'), also known as diploblasts, Epitheliozoa, or Histozoa, are a proposed basal animal clade as a sister group of the Porifera (sponges).[5][6][7][8][9] The basal eumetazoan clades are the Ctenophora and the ParaHoxozoa. Placozoa is now also seen as a eumetazoan in the ParaHoxozoa.

Several other extinct or obscure life forms, such as Iotuba and Thectardis, appear to have emerged in the group.[10] Characteristics of eumetazoans include true tissues organized into germ layers, the presence of neurons and muscles, and an embryo that goes through a gastrula stage.

Some phylogenists once speculated the sponges and eumetazoans evolved separately from different single-celled organisms, which would have meant that the animal kingdom does not form a clade (a complete grouping of all organisms descended from a common ancestor). However, genetic studies and some morphological characteristics, like the common presence of choanocytes, now unanimously support a common origin.[11]

Traditionally, eumetazoans are a major group of animals in the Five Kingdoms classification of Lynn Margulis and K. V. Schwartz, comprising the Radiata and Bilateria – all animals except the sponges.[12] When treated as a formal taxon Eumetazoa is typically ranked as a subkingdom. The name Metazoa has also been used to refer to this group, but more often refers to the Animalia as a whole. Many classification schemes do not include a subkingdom Eumetazoa.

A widely accepted hypothesis, based on molecular data (mostly 18S rRNA sequences), divides Bilateria into four superphyla: Deuterostomia, Ecdysozoa, Lophotrochozoa, and Platyzoa (sometimes included in Lophotrochozoa). The last three groups are also collectively known as Protostomia.[citation needed]

However, some skeptics[who?] emphasize inconsistencies in the new data. The zoologist Claus Nielsen argues in his 2001 book Animal Evolution: Interrelationships of the Living Phyla for the traditional divisions of Protostomia and Deuterostomia.[citation needed]
Evolutionary origins

It has been suggested that one type of molecular clock and one approach to interpretation of the fossil record both place the evolutionary origins of eumetazoa in the Ediacaran.[13] However, the earliest eumetazoans may not have left a clear impact on the fossil record and other interpretations of molecular clocks suggest the possibility of an earlier origin.[14] The discoverers of Vernanimalcula describe it as the fossil of a bilateral triploblastic animal that appeared at the end of the Marinoan glaciation prior to the Ediacaran Period, implying an even earlier origin for eumetazoans.[15]

Lankester, Ray (1877). "Notes on the Embryology and classification of the Animal kingdom: comprising a revision of speculations relative to the origin and significance of the germ-layers". Quarterly Journal of Microscopical Science (N.S.), No. 68: 399–454.
Beklemishev, V. L. The basis of the comparative anatomy of the invertebrates [Основы сравнительной анатомии беспозвоночных]. 1st ed., 1944; 2nd ed., 1950; 3rd ed. (2 vols.), 1964. English translation, 1969, [1]. Akademia Nauk, Moscow, Leningrad.
Ax, Peter (2012-12-06). Multicellular Animals: A new Approach to the Phylogenetic Order in Nature. Springer Science & Business Media. ISBN 9783642801143.
Ulrich, W. (1950). "Begriff und Einteilung der Protozoen". In Grüneberg, H. (ed.). Moderne Biologie. Festschrift zum 60. Geburtstag von Hans Nachtsheim (in German). Berlin: Peters. pp. 241–250.
Feuda, Roberto; Dohrmann, Martin; Pett, Walker; Philippe, Hervé; Rota-Stabelli, Omar; Lartillot, Nicolas; Wörheide, Gert; Pisani, Davide (2017). "Improved Modeling of Compositional Heterogeneity Supports Sponges as Sister to All Other Animals". Current Biology. 27 (24): 3864–3870.e4. doi:10.1016/j.cub.2017.11.008. PMID 29199080.
Pisani, Davide; Pett, Walker; Dohrmann, Martin; Feuda, Roberto; Rota-Stabelli, Omar; Philippe, Hervé; Lartillot, Nicolas; Wörheide, Gert (15 December 2015). "Genomic data do not support comb jellies as the sister group to all other animals". Proceedings of the National Academy of Sciences. 112 (50): 15402–15407. Bibcode:2015PNAS..11215402P. doi:10.1073/pnas.1518127112. PMC 4687580. PMID 26621703.
Simion, Paul; Philippe, Hervé; Baurain, Denis; Jager, Muriel; Richter, Daniel J.; Franco, Arnaud Di; Roure, Béatrice; Satoh, Nori; Quéinnec, Éric (3 April 2017). "A Large and Consistent Phylogenomic Dataset Supports Sponges as the Sister Group to All Other Animals" (PDF). Current Biology. 27 (7): 958–967. doi:10.1016/j.cub.2017.02.031. PMID 28318975. S2CID 4560353.
Giribet, Gonzalo (1 October 2016). "Genomics and the animal tree of life: conflicts and future prospects". Zoologica Scripta. 45: 14–21. doi:10.1111/zsc.12215.
Laumer, Christopher E; Gruber-Vodicka, Harald; Hadfield, Michael G; Pearse, Vicki B; Riesgo, Ana; Marioni, John C; Giribet, Gonzalo (2018-10-30). "Support for a clade of Placozoa and Cnidaria in genes with minimal compositional bias". eLife. 7. doi:10.7554/elife.36278. ISSN 2050-084X. PMC 6277202. PMID 30373720.
Martindale, Mark Q.; Kourakis, Matthew J. (1999). "Hox clusters: Size doesn't matter". Nature. 399 (6738): 730–731. Bibcode:1999Natur.399..730M. doi:10.1038/21530. PMID 10391234. S2CID 43414178.
H., Philippe; Derelle, R.; Lopez, P.; et al. (April 2009). "Phylogenomics revives traditional views on deep animal relationships". Current Biology. 19 (8): 706–712. doi:10.1016/j.cub.2009.02.052. PMID 19345102. S2CID 15282843.
"Systema Naturae 2000 Taxon: Subkingdom Eumetazoa". Archived 2009-03-22 at the Wayback Machine. Retrieved February 2, 2006
Peterson KJ, Butterfield NJ (July 2005). "Origin of the Eumetazoa: testing ecological predictions of molecular clocks against the Proterozoic fossil record". Proc. Natl. Acad. Sci. U.S.A. 102 (27): 9547–52. Bibcode:2005PNAS..102.9547P. doi:10.1073/pnas.0503660102. PMC 1172262. PMID 15983372.
Blair, J. E.; Hedges, S. B. (March 2005). "Molecular clocks do not support the Cambrian explosion". Molecular Biology and Evolution. 22 (3): 387–390. doi:10.1093/molbev/msi039. PMID 15537810.

Chen, J.-Y.; Bottjer, D.J.; Oliveri, P.; Dornbos, S.Q.; Gao, F.; Ruffins, S.; Chi, H.; Li, C.-W.; Davidson, E.H.; et al. (9 July 2004). "Small bilaterian fossils from 40 to 55 million years before the Cambrian". Science. 305 (5681): 218–222. Bibcode:2004Sci...305..218C. doi:10.1126/science.1099213. PMID 15178752. S2CID 115443209.

External links

Bilateria. Tree of Life web project, US National Science Foundation. 2002. 6 January 2006.
Invertebrates and the Origin of Animal Diversity
Evers, Christine A., Lisa Starr. Biology:Concepts and Applications. 6th ed. United States:Thomson, 2006. ISBN 0-534-46224-3.
Metazoa: the Animals
Nielsen, C. 2001. Animal Evolution: Interrelationships of the Living Phyla, 2nd edition, 563 pp. Oxford Univ. Press, Oxford. ISBN 0-19-850681-3
Borchiellini, C. Manuel; Alivon, E.; Boury-Esnault, N.; Vacelet, J.; Le-Parco, Y. (2001). "Sponge paraphyly and the origin of Metazoa". Journal of Evolutionary Biology. 14 (1): 171–179. doi:10.1046/j.1420-9101.2001.00244.x. PMID 29280585. S2CID 25119754.
Peterson, Kevin J.; McPeek, Mark A.; Evans, David A.D. (2005). "Tempo & mode of early animal evolution: inferences from rocks, Hox, & molecular clocks". Paleobiology. 31 (Supp 2): 36–55. doi:10.1666/0094-8373(2005)031[0036:TAMOEA]2.0.CO;2. S2CID 30787918.

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