Planulozoa Explained

Planulozoa is a clade of animals that includes the superphyla Cnidaria (jellyfish, hydrozoans, sea anemones, corals, etc.) and the Bilateria (all complex animals with bilateral symmetry, including arthropods, molluscs, vertebrates, etc.). The designation Planulozoa may be considered a synonym to ParaHoxozoa, which also contains Placozoa. Within Planulozoa, the Placozoa may be a sister of Cnidaria to the exclusion of Bilateria.[1] [2] [3] [4] The clade excludes basal animals such as the Ctenophora (comb jellies),[5] [6] [7] and Porifera (sponges).[8] [9] [10] Although this clade was sometimes used to specify a clade of Cnidaria and Bilateria to the exclusion of Placozoa (against the original intention of its proposal), this is no longer favoured due to recent data indicating a sister group relationship between Cnidaria and Placozoa,[11] another study still supports Placozoa as sister to Cnidaria+Bilateria.[12]

The phylogenetic tree indicates approximately how many millions of years ago the lineages split. Here, Planulozoa is shown sans Placozoa.[13] [14]

Planulozoa are associated with the emergence of the Zoc and ZF-NC gene domains.

Notes and References

  1. Aleshin . V. V. . Petrov . N. B. . 2002 . Molecular evidence of regression in evolution of metazoa . Zh Obshch Biol . 63 . 3 . 195–208. 12070939 .
  2. 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. en . 7 . 10.7554/elife.36278 . 30373720 . 6277202 . 2050-084X . free .
  3. Schuchert . Peter . 1993-03-01 . Trichoplax adhaerens (Phylum Placozoa) has Cells that React with Antibodies Against the Neuropeptide RFamide . Acta Zoologica . 74 . 2 . 115–117 . 10.1111/j.1463-6395.1993.tb01227.x.
  4. Syed . Tareq . Schierwater . Bernd . 2002-06-01. The evolution of the placozoa: A new morphological model . Senckenbergiana Lethaea . 82. 1 . 315–324 . 10.1007/bf03043791 . 16870420 . 0037-2110.
  5. Acoel development supports a simple planula-like urbilaterian . . Andreas Hejnol . Mark Q. Martindale . amp . 10.1098/rstb.2007.2239 . 363 . 1496 . 1493–1501 . 2008 . 18192185 . 2614228.
  6. Back in time: a new systematic proposal for the Bilateria . . Jaume Baguñà . Pere Martinez . Jordi Paps . Marta Riutort . 2008 . 10.1098/rstb.2007.2238 . 363 . 1496 . 1481–1491 . 18192186 . 2615819.
  7. Andreas Wallberg . Mikael Thollesson . James S. Farris . Ulf Jondelius . The phylogenetic position of the comb jellies (Ctenophora) and the importance of taxonomic sampling . . 20 . 6 . 2004 . 558–578 . 10.1111/j.1096-0031.2004.00041.x. 34892961 . 86185156 . free .
  8. Whelan. Nathan V.. Kocot. Kevin M. . Moroz. Tatiana P.. Mukherjee . Krishanu . Williams. Peter . Paulay. Gustav. Moroz . Leonid L. . Halanych . Kenneth M. . 2017-10-09 . Ctenophore relationships and their placement as the sister group to all other animals . Nature Ecology & Evolution . 1. 11. 1737–1746. 10.1038/s41559-017-0331-3 . 28993654. 5664179. 2017NatEE...1.1737W . 2397-334X.
  9. C. Borchiellini . M. Manuel . E. Alivon . N. Boury-Esnault . J. Vacelet . Y. Le Parco . Sponge paraphyly and the origin of Metazoa . . 14 . 1 . 171–179 . 2001 . 10.1046/j.1420-9101.2001.00244.x. 29280585 . free .
  10. Pisani . Davide . Pett . Walker . Dohrmann. Martin . Feuda. Roberto. Rota-Stabelli . Omar . Philippe . Hervé . Lartillot. Nicolas. Wörheide . Gert . 2015-12-01 . 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 . 10.1073/pnas.1518127112 . 4687580 . 26621703. 2015PNAS..11215402P . free .
  11. Book: Giribet, Gonzalo. The invertebrate tree of life. 2020. Gregory D. Edgecombe. 978-0-691-19706-7. Princeton, New Jersey. 46. 1129197548.
  12. Najle . Sebastián R. . Grau-Bové . Xavier . Elek . Anamaria . Navarrete . Cristina . Cianferoni . Damiano . Chiva . Cristina . Cañas-Armenteros . Didac . Mallabiabarrena . Arrate . Kamm . Kai . Sabidó . Eduard . Gruber-Vodicka . Harald . Schierwater . Bernd . Serrano . Luis . Sebé-Pedrós . Arnau . September 19, 2023 . Stepwise emergence of the neuronal gene expression program in early animal evolution . Cell . en . 186 . 21 . 4676–4693.e29 . 10.1016/j.cell.2023.08.027 . 10580291 . 37729907.
  13. 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 . 10.1098/rstb.2007.2233 . 18192191 . 2614224.
  14. Web site: Raising the Standard in Fossil Calibration. Fossil Calibration Database. 3 March 2018.

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