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Temporal range: 605.2 –0 Ma Ediacaran-Present
Animalia diversity.jpg
Diversity of parahoxozoans
Scientific classification e
Kingdom: Animalia
Subkingdom: Eumetazoa
Clade: ParaHoxozoa
Ryan et al., 2010

ParaHoxozoa (or Parahoxozoa) is a clade of animals that consists of Bilateria, Placozoa, and Cnidaria.[1] The relationship of this clade relative to the two other animal lineages Ctenophora and Porifera is debated. Some phylogenomic studies have presented evidence supporting Ctenophora as the sister to Parahoxozoa and Porifera as the sister group to the rest of animals (e.g. [2][3][4][5][6][7]).[excessive citations] Some studies have presented evidence supporting Porifera as the sister to Parahoxozoa and Ctenophora as the sister group to the rest of animals (e.g. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]).[excessive citations]


The tree below, which is congruent with the vast majority of these phylogenomic studies, conveys this uncertainty with a polytomy.




CtenophoraMertensia ovum.png

Porifera Reef3859 - Flickr - NOAA Photo Library.jpg


PlacozoaTrichoplax adhaerens photograph.png


CnidariaMedusae of world-vol03 fig360 Atolla chuni.jpg

BilateriaAcrodipsas brisbanensis.jpg

ParaHoxozoa or Parahoxozoa[edit]

Though "ParaHox" genes are usually referred to in CamelCase and the original paper that named the clade used "ParaHoxozoa", the single initial cap format "Parahoxozoa" has become more common in the literature as CamelCase is not standard in zoological nomenclature.


Parahoxozoa was defined by the presence of several gene (sub)classes (HNF, CUT, PROS, ZF, CERS, K50, S50-PRD), as well as Hox/ParaHox-ANTP from which the name of this clade originated. It was later proposed[24][25] and contested[26] that a gene of the same class (ANTP) as the Hox/ParaHox, the NK gene and the Cdx Parahox gene, is also present in Porifera, the sponges. Regardless of whether a ParaHox gene is ever definitively identified, Parahoxozoa, as originally defined, is monophyletic and therefore continues to be used as such.[27]

Planula-acoel, triploblasty, and bilaterian similarities[edit]

The original Bilateria are hypothesized to be a bottom dwelling worm with a single body opening.[28] A through-gut may already have developed with the Ctenophora however.[29] The through-gut may have developed from the corners of a single opening with lips fusing. E.g. Acoela resemble the planula larvae of some Cnidaria, which exhibit some bilaterian symmetry. They are vermiform, just as the cnidarian Buddenbrockia is.[30][31][32] Placozoa has been noted to resemble planula.[33] Usually, "Planulozoa" is to the exclusion of Placozoa, but not necessarily. In this case it appears synonymous with Parahoxozoa.[34] Triploblasty developed before the Cnidaria-Bilateria radiation as well.[35]


  1. ^ Ryan, Joseph F.; Pang, Kevin; Mullikin, James C.; Martindale, Mark Q.; Baxevanis, Andreas D. (2010-10-04). "The homeodomain complement of the ctenophore Mnemiopsis leidyi suggests that Ctenophora and Porifera diverged prior to the Parahoxozoa". EvoDevo. 1 (1): 9. doi:10.1186/2041-9139-1-9. ISSN 2041-9139. PMC 2959044. PMID 20920347.
  2. ^ Pick, K. S.; Philippe, H.; Schreiber, F.; Erpenbeck, D.; Jackson, D. J.; Wrede, P.; Wiens, M.; Alie, A.; Morgenstern, B.; Manuel, M.; Worheide, G. (2010). "Improved Phylogenomic Taxon Sampling Noticeably Affects Nonbilaterian Relationships". Molecular Biology and Evolution. 27 (9): 1983–1987. doi:10.1093/molbev/msq089. ISSN 0737-4038. PMC 2922619. PMID 20378579.
  3. ^ Nosenko, Tetyana; Schreiber, Fabian; Adamska, Maja; Adamski, Marcin; Eitel, Michael; Hammel, Jörg; Maldonado, Manuel; Müller, Werner E.G.; Nickel, Michael; Schierwater, Bernd; Vacelet, Jean; Wiens, Matthias; Wörheide, Gert (2013). "Deep metazoan phylogeny: When different genes tell different stories". Molecular Phylogenetics and Evolution. 67 (1): 223–233. doi:10.1016/j.ympev.2013.01.010. ISSN 1055-7903. PMID 23353073.
  4. ^ 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. ISSN 0027-8424. PMC 4687580. PMID 26621703.
  5. ^ 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. 6 (24): 3864–3870.e4. doi:10.1016/j.cub.2017.11.008. PMID 29199080.
  6. ^ 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 (Submitted manuscript). 27 (7): 958–967. doi:10.1016/j.cub.2017.02.031. ISSN 0960-9822. PMID 28318975. S2CID 4560353.
  7. ^ Leclère, Lucas; Horin, Coralie; Chevalier, Sandra; Lapébie, Pascal; Dru, Philippe; Peron, Sophie; Jager, Muriel; Condamine, Thomas; Pottin, Karen; Romano, Séverine; Steger, Julia; Sinigaglia, Chiara; Barreau, Carine; Quiroga Artigas, Gonzalo; Ruggiero, Antonella; Fourrage, Cécile; Kraus, Johanna E. M.; Poulain, Julie; Aury, Jean-Marc; Wincker, Patrick; Quéinnec, Eric; Technau, Ulrich; Manuel, Michaël; Momose, Tsuyoshi; Houliston, Evelyn; Copley, Richard R. (2019). "The genome of the jellyfish Clytia hemisphaerica and the evolution of the cnidarian life-cycle". Nature Ecology & Evolution. 3 (5): 801–810. doi:10.1038/s41559-019-0833-2. ISSN 2397-334X. PMID 30858591.
  8. ^ Dunn, Casey W.; Hejnol, Andreas; Matus, David Q.; Pang, Kevin; Browne, William E.; Smith, Stephen A.; Seaver, Elaine; Rouse, Greg W.; Obst, Matthias; Edgecombe, Gregory D.; Sørensen, Martin V.; Haddock, Steven H. D.; Schmidt-Rhaesa, Andreas; Okusu, Akiko; Kristensen, Reinhardt Møbjerg; Wheeler, Ward C.; Martindale, Mark Q.; Giribet, Gonzalo (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. ISSN 0028-0836. PMID 18322464. S2CID 4397099.
  9. ^ Hejnol, Andreas; Obst, Matthias; Stamatakis, Alexandros; Ott, Michael; Rouse, Greg W.; Edgecombe, Gregory D.; Martinez, Pedro; Baguñà, Jaume; Bailly, Xavier; Jondelius, Ulf; Wiens, Matthias; Müller, Werner E. G.; Seaver, Elaine; Wheeler, Ward C.; Martindale, Mark Q.; Giribet, Gonzalo; Dunn, Casey W. (2009). "Assessing the root of bilaterian animals with scalable phylogenomic methods". Proceedings of the Royal Society B: Biological Sciences. 276 (1677): 4261–4270. doi:10.1098/rspb.2009.0896. ISSN 0962-8452. PMC 2817096. PMID 19759036.
  10. ^ Ryan, J. F.; Pang, K.; Schnitzler, C. E.; Nguyen, A.-D.; Moreland, R. T.; Simmons, D. K.; Koch, B. J.; Francis, W. R.; Havlak, P.; Smith, S. A.; Putnam, N. H.; Haddock, S. H. D.; Dunn, C. W.; Wolfsberg, T. G.; Mullikin, J. C.; Martindale, M. Q.; Baxevanis, A. D. (2013). "The Genome of the Ctenophore Mnemiopsis leidyi and Its Implications for Cell Type Evolution". Science. 342 (6164): 1242592. doi:10.1126/science.1242592. ISSN 0036-8075. PMC 3920664. PMID 24337300.
  11. ^ Moroz, Leonid L.; Kocot, Kevin M.; Citarella, Mathew R.; Dosung, Sohn; Norekian, Tigran P.; Povolotskaya, Inna S.; Grigorenko, Anastasia P.; Dailey, Christopher; Berezikov, Eugene; Buckley, Katherine M.; Ptitsyn, Andrey; Reshetov, Denis; Mukherjee, Krishanu; Moroz, Tatiana P.; Bobkova, Yelena; Yu, Fahong; Kapitonov, Vladimir V.; Jurka, Jerzy; Bobkov, Yuri V.; Swore, Joshua J.; Girardo, David O.; Fodor, Alexander; Gusev, Fedor; Sanford, Rachel; Bruders, Rebecca; Kittler, Ellen; Mills, Claudia E.; Rast, Jonathan P.; Derelle, Romain; Solovyev, Victor V.; Kondrashov, Fyodor A.; Swalla, Billie J.; Sweedler, Jonathan V.; Rogaev, Evgeny I.; Halanych, Kenneth M.; Kohn, Andrea B. (2014). "The ctenophore genome and the evolutionary origins of neural systems". Nature. 510 (7503): 109–114. Bibcode:2014Natur.510..109M. doi:10.1038/nature13400. ISSN 0028-0836. PMC 4337882. PMID 24847885.
  12. ^ Chang, E. Sally; Neuhof, Moran; Rubinstein, Nimrod D.; Diamant, Arik; Philippe, Hervé; Huchon, Dorothée; Cartwright, Paulyn (2015). "Genomic insights into the evolutionary origin of Myxozoa within Cnidaria". Proceedings of the National Academy of Sciences. 112 (48): 14912–14917. Bibcode:2015PNAS..11214912C. doi:10.1073/pnas.1511468112. ISSN 0027-8424. PMC 4672818. PMID 26627241.
  13. ^ Whelan, Nathan V.; Kocot, Kevin M.; Moroz, Leonid L.; Halanych, Kenneth M. (2015). "Error, signal, and the placement of Ctenophora sister to all other animals". Proceedings of the National Academy of Sciences. 112 (18): 5773–5778. Bibcode:2015PNAS..112.5773W. doi:10.1073/pnas.1503453112. ISSN 0027-8424. PMC 4426464. PMID 25902535.
  14. ^ Torruella, Guifré; de Mendoza, Alex; Grau-Bové, Xavier; Antó, Meritxell; Chaplin, Mark A.; del Campo, Javier; Eme, Laura; Pérez-Cordón, Gregorio; Whipps, Christopher M.; Nichols, Krista M.; Paley, Richard; Roger, Andrew J.; Sitjà-Bobadilla, Ariadna; Donachie, Stuart; Ruiz-Trillo, Iñaki (2015). "Phylogenomics Reveals Convergent Evolution of Lifestyles in Close Relatives of Animals and Fungi". Current Biology. 25 (18): 2404–2410. doi:10.1016/j.cub.2015.07.053. ISSN 0960-9822. PMID 26365255.
  15. ^ Borowiec, Marek L.; Lee, Ernest K.; Chiu, Joanna C.; Plachetzki, David C. (2015). "Extracting phylogenetic signal and accounting for bias in whole-genome data sets supports the Ctenophora as sister to remaining Metazoa". BMC Genomics. 16 (1): 987. doi:10.1186/s12864-015-2146-4. ISSN 1471-2164. PMC 4657218. PMID 26596625.
  16. ^ Shen, Xing-Xing; Hittinger, Chris Todd; Rokas, Antonis (2017). "Contentious relationships in phylogenomic studies can be driven by a handful of genes". Nature Ecology & Evolution. 1 (5): 126. doi:10.1038/s41559-017-0126. ISSN 2397-334X. PMC 5560076. PMID 28812701.
  17. ^ Arcila, Dahiana; Ortí, Guillermo; Vari, Richard; Armbruster, Jonathan W.; Stiassny, Melanie L. J.; Ko, Kyung D.; Sabaj, Mark H.; Lundberg, John; Revell, Liam J.; Betancur-R., Ricardo (2017). "Genome-wide interrogation advances resolution of recalcitrant groups in the tree of life". Nature Ecology & Evolution. 1 (2): 20. doi:10.1038/s41559-016-0020. ISSN 2397-334X. PMID 28812610. S2CID 16535732.
  18. ^ Whelan, Nathan V.; Kocot, Kevin M.; Moroz, Tatiana P.; Mukherjee, Krishanu; Williams, Peter; Paulay, Gustav; Moroz, Leonid L.; Halanych, Kenneth M. (2017). "Ctenophore relationships and their placement as the sister group to all other animals". Nature Ecology & Evolution. 1 (11): 1737–1746. doi:10.1038/s41559-017-0331-3. ISSN 2397-334X. PMC 5664179. PMID 28993654.
  19. ^ Pandey, Akanksha; Braun, Edward L. (2021). "The Roles of Protein Structure, Taxon Sampling, and Model Complexity in Phylogenomics: A Case Study Focused on Early Animal Divergences". Biophysica. 1 (2): 87–105. doi:10.3390/biophysica1020008. ISSN 2673-4125.
  20. ^ Laumer, Christopher E.; Fernández, Rosa; Lemer, Sarah; Combosch, David; Kocot, Kevin M.; Riesgo, Ana; Andrade, Sónia C. S.; Sterrer, Wolfgang; Sørensen, Martin V.; Giribet, Gonzalo (2019). "Revisiting metazoan phylogeny with genomic sampling of all phyla". Proceedings of the Royal Society B: Biological Sciences. 286 (1906): 20190831. doi:10.1098/rspb.2019.0831. ISSN 0962-8452. PMC 6650721. PMID 31288696.
  21. ^ Jeon, Yeonsu; Park, Seung Gu; Lee, Nayun; Weber, Jessica A; Kim, Hui-Su; Hwang, Sung-Jin; Woo, Seonock; Kim, Hak-Min; Bhak, Youngjune; Jeon, Sungwon; Lee, Nayoung; Jo, Yejin; Blazyte, Asta; Ryu, Taewoo; Cho, Yun Sung; Kim, Hyunho; Lee, Jung-Hyun; Yim, Hyung-Soon; Bhak, Jong; Yum, Seungshic; Ochman, Howard (2019). "The Draft Genome of an Octocoral, Dendronephthya gigantea". Genome Biology and Evolution. 11 (3): 949–953. doi:10.1093/gbe/evz043. ISSN 1759-6653. PMC 6447388. PMID 30825304.
  22. ^ Kim, Hak-Min; Weber, Jessica A.; Lee, Nayoung; Park, Seung Gu; Cho, Yun Sung; Bhak, Youngjune; Lee, Nayun; Jeon, Yeonsu; Jeon, Sungwon; Luria, Victor; Karger, Amir; Kirschner, Marc W.; Jo, Ye Jin; Woo, Seonock; Shin, Kyoungsoon; Chung, Oksung; Ryu, Jae-Chun; Yim, Hyung-Soon; Lee, Jung-Hyun; Edwards, Jeremy S.; Manica, Andrea; Bhak, Jong; Yum, Seungshic (2019). "The genome of the giant Nomura's jellyfish sheds light on the early evolution of active predation". BMC Biology. 17 (1): 28. doi:10.1186/s12915-019-0643-7. ISSN 1741-7007. PMC 6441219. PMID 30925871.
  23. ^ Erives, Albert; Fritzsch, Bernd (2020). "A Screen for Gene Paralogies Delineating Evolutionary Branching Order of Early Metazoa". G3: Genes, Genomes, Genetics. 10 (2): 811–826. doi:10.1534/g3.119.400951. ISSN 2160-1836. PMC 7003098. PMID 31879283.
  24. ^ Fortunato, Sofia A. V.; Adamski, Marcin; Ramos, Olivia Mendivil; Leininger, Sven; Liu, Jing; Ferrier, David E. K.; Adamska, Maja (2014-10-30). "Calcisponges have a ParaHox gene and dynamic expression of dispersed NK homeobox genes". Nature. 514 (7524): 620–623. Bibcode:2014Natur.514..620F. doi:10.1038/nature13881. hdl:10023/6597. ISSN 0028-0836. PMID 25355364. S2CID 205241127.
  25. ^ Larroux, Claire; Fahey, Bryony; Degnan, Sandie M.; Adamski, Marcin; Rokhsar, Daniel S.; Degnan, Bernard M. (1996). "The NK Homeobox Gene Cluster Predates the Origin of Hox Genes". Current Biology. 17 (8): 706–710. doi:10.1016/j.cub.2007.03.008. PMID 17379523. S2CID 18994676.
  26. ^ Pastrana, Claudia C.; DeBiasse, Melissa B.; Ryan, Joseph F. (2019). "Sponges lack ParaHox genes". Genome Biology and Evolution. 11 (4): 1250–1257. doi:10.1093/gbe/evz052. PMC 6486804. PMID 30859199.
  27. ^ 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. ISSN 1463-6409.
  28. ^ Cannon, Johanna Taylor; Vellutini, Bruno Cossermelli; Smith, Julian; Ronquist, Fredrik; Jondelius, Ulf; Hejnol, Andreas (2016). "Xenacoelomorpha is the sister group to Nephrozoa". Nature (Submitted manuscript). 530 (7588): 89–93. Bibcode:2016Natur.530...89C. doi:10.1038/nature16520. PMID 26842059. S2CID 205247296.
  29. ^ Browne, William E.; Amemiya, Chris T.; Swalla, Billie J.; Warren, Kaitlyn J.; Vandepas, Lauren E.; Presnell, Jason S. (2016-10-24). "The Presence of a Functionally Tripartite Through-Gut in Ctenophora Has Implications for Metazoan Character Trait Evolution". Current Biology. 26 (20): 2814–2820. doi:10.1016/j.cub.2016.08.019. ISSN 0960-9822. PMID 27568594.
  30. ^ Jiménez-Guri, Eva; Philippe, Hervé; Okamura, Beth; Holland, Peter W. H. (2007-07-06). "Buddenbrockia Is a Cnidarian Worm". Science. 317 (5834): 116–118. Bibcode:2007Sci...317..116J. doi:10.1126/science.1142024. ISSN 0036-8075. PMID 17615357. S2CID 5170702.
  31. ^ Baguñà, Jaume; Martinez, Pere; Paps, Jordi; Riutort, Marta (2008-04-27). "Back in time: a new systematic proposal for the Bilateria". Philosophical Transactions of the Royal Society B: Biological Sciences. 363 (1496): 1481–1491. doi:10.1098/rstb.2007.2238. ISSN 0962-8436. PMC 2615819. PMID 18192186.
  32. ^ Genikhovich, Grigory; Technau, Ulrich (2017-10-01). "On the evolution of bilaterality". Development. 144 (19): 3392–3404. doi:10.1242/dev.141507. ISSN 0950-1991. PMID 28974637.
  33. ^ Syed, Tareq; Schierwater, Bernd (2002). "The evolution of the placozoa: A new morphological model". Senckenbergiana Lethaea. 82 (1): 315–324. doi:10.1007/bf03043791. ISSN 0037-2110. S2CID 16870420.
  34. ^ Wallberg, Andreas; Thollesson, Mikael; Farris, James S.; Jondelius, Ulf (2004). "The phylogenetic position of the comb jellies (Ctenophora) and the importance of taxonomic sampling". Cladistics. 20 (6): 558–578. doi:10.1111/j.1096-0031.2004.00041.x. ISSN 0748-3007. PMID 34892961. S2CID 86185156.
  35. ^ Boero, F.; Schierwater, B.; Piraino, S. (2007-06-01). "Cnidarian milestones in metazoan evolution". Integrative and Comparative Biology. 47 (5): 693–700. doi:10.1093/icb/icm041. ISSN 1540-7063. PMID 21669750.