Biology:Ambulacraria
Ambulacraria /ˌæmbjuːləˈkrɛəriə/, or Coelomopora /siːləˈmɒpərə/, is a clade of invertebrate phyla that includes echinoderms and hemichordates;[1] a member of this group is called an ambulacrarian. Phylogenetic analysis suggests the echinoderms and hemichordates separated around 533 million years ago.[2] The Ambulacraria are part of the deuterostomes, a clade that also includes the many Chordata, and the few extinct species belonging to the Vetulicolia.
Etymology
Ambulacraria, from the latin ambulacrum, meaning "a walk planted with trees",[3] was named by Élie Metchnikoff in reference to the larval similarities including a folded band lined with cillia that are used for both feeding and locomotion.[4] Metchnikoff also noted similarities among the coleomic systems of echinoderms and hemichordates and their larvae.[5]
Phylogeny
The two living clades with representative organisms are:
- Echinodermata (sea stars, sea urchins, brittle stars, sea cucumbers, feather stars, sea lilies, etc.)
- Hemichordata (acorn worms (Enteropnuesta) and Pterobranchia (including Graptolithina))[6]
(These together sometimes are called the lower deuterostomes.[7])
Whether the Xenacoelomorpha clade is the sister group to the Ambulacraria remains a contentious issue, with some authors arguing that the former should be placed more basally among metazoans,[8][9][1] and other authors asserting that the best choices of phylogenetic methods support the position of Xenacoelomorpha as the sister group to Ambulacraria.[10][11]
A third, extinct clade known as the Cambroernida has recently been recognized as part of the ambulacrarian stem group. The morphology of this group suggests that the ancestral deuterostome did not possess a post-anal tail, which evolved convergently in chordates and hemichordates, and possessed gill slits but not additional structures such as the gill bars found in hemichordates.[12]
Two extinct taxa of uncertain placement, the Vetulocystida and Yanjiahella, have each been proposed as either stem-group echinoderms[13][14] or stem-group ambulacrarians.[15][16] Vetulocystids have also been tentatively proposed as the basal-most stem-group chordates,[17] while Yanjiahella has also been proposed to be a stem-group hemichordate.[16]
The following cladogram is based on a simplification of Li et al. 2023,[12] with the possible placements of uncertain potential ambulacrarians shown with dashed lines and question marks:
| ? Xenambulacraria |
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| Chordata |
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(total group)
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Ontogeny
As for many animals, the egg cell of any extant ambulacrarian divides and develops into a blastula ("cell ball"), which develops into a triploblast ("three-layered") gastrula. The gastrula then develops into a dipleurula larva form in the Asteroidea, Holothuroidea, Crinoidea, and Hemichordata, and into a pluteus larva form in the Echinoidea and Ophiuroidea.[7][18] This, in its turn, is developed in various different kinds of larvae for different taxa of ambulacrarians.
It has been suggested that the adult form of the last common ancestor of the ambulacrarians was anatomically similar to the dipleurula larva; this hypothetic ancestor sometimes also is called dipleurula.[19]
References
- ↑ 1.0 1.1 Cannon, Johanna Taylor; Vellutini, Bruno Cossermelli; Smith, Julian; Ronquist, Fredrik; Jondelius, Ulf; Hejnol, Andreas (2016). "Xenacoelomorpha is the sister group to Nephrozoa". Nature 530 (7588): 89–93. doi:10.1038/nature16520. PMID 26842059. Bibcode: 2016Natur.530...89C. http://urn.kb.se/resolve?urn=urn:nbn:se:nrm:diva-1844.
- ↑ "Sea Cucumber Genome Imparts Insight on Genes Linked to Organ Regeneration". 12 October 2017. https://www.genomeweb.com/sequencing/sea-cucumber-genome-imparts-insight-genes-linked-organ-regeneration.
- ↑ "ambulacrum". http://www.thefreedictionary.com/ambulacra.
- ↑ Smith, Andrew B.. Encyclopedia of Life Support Systems (EOLSS). Paris: Developed under the Auspices of the UNESCO, Eolss Publishers. https://www.eolss.net/sample-chapters/c03/E6-71-90-10.pdf.
- ↑ Nielsen, Claus (17 December 2013). "Ambulacraria". Animal Evolution: Interrelationships of the Living Phyla (3rd, online ed.). Oxford: Oxford Academic. doi:10.1093/acprof:oso/9780199606023.003.0057.
- ↑ Mitchell, C. E.; Melchin, M. J.; Cameron, C. B.; Maletz, J. (2013). "Phylogenetic analysis reveals that Rhabdopleura is an extant graptolite". Lethaia 46 (1): 34–56. doi:10.1111/j.1502-3931.2012.00319.x.
- ↑ 7.0 7.1 Lacalli, Thurston Castle. "Tutorial". University of Saskatchewan. http://scaa.usask.ca/gallery/lacalli/tutorial/tutorial_all.php.
- ↑ Edgecombe, Gregory D.; Giribet, Gonzalo; Dunn, Casey W.; Hejnol, Andreas; Kristensen, Reinhardt M.; Neves, Ricardo C.; Rouse, Greg W.; Worsaae, Katrine 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. http://nrs.harvard.edu/urn-3:HUL.InstRepos:27755241.
- ↑ Rouse, Greg W.; Wilson, Nerida G.; Carvajal, Jose I.; Vriejenhoek, Robert C. (4 February 2016). "New deep-sea species of Xenoturbella and the position of Xenacoelomorpha". Nature 530 (2): 94–97. doi:10.1038/nature16545. PMID 26842060. Bibcode: 2016Natur.530...94R. https://www.nature.com/articles/nature16545.
- ↑ Herve Philippe (3 June 2019). "Mitigating Anticipated Effects of Systematic Errors Supports Sister-Group Relationship between Xenacoelomorpha and Ambulacraria". Current Biology 29 (11): 1818–1826. doi:10.1016/j.cub.2019.04.009. PMID 31104936.
- ↑ Kapli, Paschalia; Telford, Maximilian J. (11 December 2020). "Topology-dependent asymmetry in systematic errors affects phylogenetic placement of Ctenophora and Xenacoelomorpha". Science Advances 6 (50). doi:10.1126/sciadv.abc5162. PMID 33310849. Bibcode: 2020SciA....6.5162K.
- ↑ 12.0 12.1 Li, Yujing; Dunn, Frances S.; Murdock, Duncan J.E.; Guo, Jin; Rahman, Imran A.; Cong, Peiyun (May 10, 2023). "Cambrian stem-group ambulacrarians and the nature of the ancestral deuterostome". Current Biology 33 (12): 2359–2366.e2. doi:10.1016/j.cub.2023.04.048. PMID 37167976. Bibcode: 2023CBio...33E2359L.
- ↑ Shu, D.-G.; Conway Morris, S.; Han, J.; Zhang, Z.-F.; Liu, J.-N. (2004). "Ancestral echinoderms from the Chengjiang deposits of China". Nature 430 (6998): 422–428. doi:10.1038/nature02648. PMID 15269760. Bibcode: 2004Natur.430..422S. https://www.nature.com/articles/nature02648.
- ↑ Topper, Timothy P.; Guo, Junfeng; Clausen, Sébastien; Skovsted, Christian B.; Zhang, Zhifei (2019-03-25). "A stem group echinoderm from the basal Cambrian of China and the origins of Ambulacraria" (in en). Nature Communications 10 (1): 1366. doi:10.1038/s41467-019-09059-3. ISSN 2041-1723. PMID 30911013. Bibcode: 2019NatCo..10.1366T.
- ↑ Conway Morris, Simon; Halgedahl, Susan L.; Selden, Paul; Jarrard, Richard D. (2015). "Rare primitive deuterostomes from the Cambrian (Series 3) of Utah". Journal of Paleontology 89 (4): 631–636. doi:10.1017/jpa.2015.40. Bibcode: 2015JPal...89..631C. https://core.ac.uk/download/pdf/51378622.pdf.
- ↑ 16.0 16.1 Zamora, Samuel; Wright, David F.; Mooi, Rich; Lefebvre, Bertrand; Guensburg, Thomas E.; Gorzelak, Przemysław; David, Bruno; Sumrall, Colin D. et al. (2020-03-09). "Re-evaluating the phylogenetic position of the enigmatic early Cambrian deuterostome Yanjiahella" (in en). Nature Communications 11 (1): 1286. doi:10.1038/s41467-020-14920-x. ISSN 2041-1723. PMID 32152310. Bibcode: 2020NatCo..11.1286Z.
- ↑ Mussini, G.; Smith, M. P.; Vinther, J.; Rahman, I. A.; Murdock, D. J. E.; Harper, D. A. T.; Dunn, F. S. (2024). "A new interpretation of Pikaia reveals the origins of the chordate body plan". Current Biology 34 (13): 2980–2989.e2. doi:10.1016/j.cub.2024.05.026. PMID 38866005. Bibcode: 2024CBio...34.2980M.
- ↑ Byrne, Maria; Nakajima, Yoko; Chee, Francis C.; Burke, Robert D. (2007). "Apical organs in echinoderm larvae: insights into larval evolution in the Ambulacraria". Evolution & Development 9: 434–435, 438–440. doi:10.1111/j.1525-142X.2007.00189.x. https://eds.s.ebscohost.com/eds/pdfviewer/pdfviewer?vid=2&sid=f505dbea-6289-44f3-8005-19035ca0927b%40redis.
- ↑ "Dipleurula" (in de). Lexikon der Biologie. Spektrum Akademischer Verlag. Heidelberg. 1999. http://www.spektrum.de/lexikon/biologie/dipleurula/18496.
Wikidata ☰ Q136956 entry
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