ParaHoxozoa
ParaHoxozoa is a proposed group within taxonomy. It would be a clade, above phylum but below a kingdom.
| ParaHoxozoa | |
|---|---|
Scientific classification 
| |
| Kingdom: | Animalia |
| Subkingdom: | Eumetazoa |
| Clade: | ParaHoxozoa Ryan et al., 2010 |
| Clades | |
It would include the Bilateria, the Placozoa and the Cnidarians.[1][2][3][4][5][6][7]
Characteristics
Parahoxozoa is named after the groups of genes that scientists found in the organisms in it: (sub)classes (HNF, CUT, PROS, ZF, CERS, K50, S50-PRD) and Hox/ParaHox-ANTP. Some scientists said they thought a similar gene, ANTP, the NK gene, and the Cdx Parahox gene were also in sponges in the phylum Porifera, but for now, Parahoxozoa does not have sponges in it.[8][9][10][4]
| Choanozoa |
| ||||||||||||||||||||||||||||||||||||||||||||||||
Scientists are not sure where to put Placozoa. They think it could be a sister clade to the other Parahoxozoa (the Planulozoa hypothesis) or sister of Cnidaria.
Planula-acoel, triploblasty, and bilaterian similarities
The first bilateral organisms (the first living things that were symmetrical from side to side) were worms which lived on the bottom of bodies of water. This type of worm probably had only one opening in its body instead of both a mouth and an anus, as bilateral organisms do today.[11] A through-gut may already have developed with the ctenophora.[12] The through-gut, the tubelike digestive system with two ends, may have evolved when the organism's one hole closed in the middle. For example, Acoela look like the planula larvae of some cnidarians.[13][14][15]
ParaHoxozoa Media
Reef3859 - Flickr - NOAA Photo Library
Trichoplax adhaerens photograph
References
- ↑ Feuda, Roberto. Improved Modeling of Compositional Heterogeneity Supports Sponges as Sister to All Other Animals (in en). Current Biology 6 (24) (2017). p. 3864–3870.e4. doi:10.1016/j.cub.2017.11.008.
- ↑ Pisani, Davide. Genomic data do not support comb jellies as the sister group to all other animals (in en). Proceedings of the National Academy of Sciences 112 (50) (15 December 2015). p. 15402–15407. doi:10.1073/pnas.1518127112.
- ↑ Simion, Paul. A Large and Consistent Phylogenomic Dataset Supports Sponges as the Sister Group to All Other Animals (in English). Current Biology 27 (7) (3 April 2017). p. 958–967. doi:10.1016/j.cub.2017.02.031.
- ↑ 4.0 4.1 Giribet, Gonzalo. Genomics and the animal tree of life: conflicts and future prospects (in en). Zoologica Scripta 45 (1 October 2016). p. 14–21. doi:10.1111/zsc.12215.
- ↑ Laumer, Christopher E. Support for a clade of Placozoa and Cnidaria in genes with minimal compositional bias (in en). eLife 7 (2018-10-30). doi:10.7554/elife.36278.
- ↑ Ryan, Joseph F.. The homeodomain complement of the ctenophore Mnemiopsis leidyi suggests that Ctenophora and Porifera diverged prior to the ParaHoxozoa. EvoDevo 1 (1) (2010-10-04). p. 9. doi:10.1186/2041-9139-1-9.
- ↑ Eitel, Michael. A taxogenomics approach uncovers a new genus in the phylum Placozoa (in en). bioRxiv (2017-10-13). p. 202119. doi:10.1101/202119.
- ↑ Fortunato, Sofia A. V.. Calcisponges have a ParaHox gene and dynamic expression of dispersed NK homeobox genes (in en). Nature 514 (7524) (2014-10-30). p. 620–623. doi:10.1038/nature13881.
- ↑ Larroux, Claire. The NK Homeobox Gene Cluster Predates the Origin of Hox Genes. Current Biology 17 (8) (1996). p. 706–710. doi:10.1016/j.cub.2007.03.008.
- ↑ Ryan, Joseph F.. Sponges lack ParaHox genes (in en). Genome Biology and Evolution 11 (4) (2019). p. 1250–1257. doi:10.1093/gbe/evz052.
- ↑ Cannon, Johanna Taylor. Xenacoelomorpha is the sister group to Nephrozoa. Nature 530 (7588) (2016). p. 89–93. doi:10.1038/nature16520.
- ↑ Browne, William E.. The presence of a functionally tripartite through-gut in Ctenophora has implications for metazoan character trait evolution (in English). Current Biology 26 (20) (2016-10-24). p. 2814–2820. doi:10.1016/j.cub.2016.08.019.
- ↑ Jiménez-Guri, Eva. Buddenbrockia Is a Cnidarian Worm (in en). Science 317 (5834) (2007-07-06). p. 116–118. doi:10.1126/science.1142024.
- ↑ Baguñà, Jaume. Back in time: a new systematic proposal for the Bilateria (in en). Philosophical Transactions of the Royal Society B: Biological Sciences 363 (1496) (2008-04-27). p. 1481–1491. doi:10.1098/rstb.2007.2238.
- ↑ Genikhovich, Grigory. On the evolution of bilaterality (in en). Development 144 (19) (2017-10-01). p. 3392–3404. doi:10.1242/dev.141507.