Wikipedia

Deuterostome

For the cell biology protein structure, see Deuterosome.

Deuterostomes (from Greek: lit. 'mouth second') are bilaterian animals of the superphylum Deuterostomia (/ˌdjuːtərəˈstoʊmi.ə/),[3][4] typically characterized by their anus forming before the mouth during embryonic development. Deuterostomia is further divided into four phyla: Chordata, Echinodermata, Hemichordata, and the extinct Vetulicolia known from Cambrian fossils. The extinct clade Cambroernida is thought to be a member of Deuterostomia.

Deuterostomes
Temporal range: Earliest Cambrian–Present (Possible Ediacaran record, 557 Ma[1])
TunicateTetrapodActinopterygiiStarfishSea urchinCrinoidGraptoliteAcorn wormVetulicolia
Diversity of deuterostomes
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Clade: ParaHoxozoa
Clade: Bilateria
Clade: Nephrozoa
Superphylum: Deuterostomia
Grobben, 1908
Clades

In deuterostomes, the developing embryo's first opening (the blastopore) becomes the anus and cloaca, while the mouth is formed at a different site later on. This was initially the group's distinguishing characteristic, but deuterostomy has since been discovered among protostomes as well.[5] The deuterostomes are also known as enterocoelomates, because their coelom develops through enterocoely.

Deuterostomia's sister clade is Protostomia, animals that develop mouth first and whose digestive tract development is more varied. Protostomia includes the ecdysozoans (panarthropods, nematoids, penis worms, mud dragons etc.) and spiralians (mollusks, annelids, flatworms, rotifers, arrow worms, etc.), as well as the extinct Kimberella.

Deuterostomia and Protostomia, together with their outgroup Xenacoelomorpha, constitute the large infrakingdom Bilateria, i.e. animals with bilateral symmetry and three germ layers.

Systematics

edit

History of classification

edit

Initially, Deuterostomia included the phyla Brachiopoda,[6] Bryozoa,[7] Chaetognatha,[8] and Phoronida[6] based on morphological and embryological characteristics. However, Deuterostomia was redefined in 1995 based on DNA molecular sequence analyses, leading to the removal of the lophophorates which was later combined with other protostome animals to form the superphylum Lophotrochozoa.[9] The arrow worms may also be deuterostomes,[8] but molecular studies have placed them in the protostomes more often.[10][11] Genetic studies have also revealed that deuterostomes have more than 30 genes not found in any other animal groups, but which yet are present in some marine algae and prokaryotes. This could mean they are very ancient genes that were lost in other organisms, or that a common ancestor acquired them through horizontal gene transfer.[12]

Taxonomy

edit
See also: List of bilateral animal orders

This is the generally agreed upon phylogeny of the deuterostomes:

There is a possibility that Ambulacraria is the sister clade to Xenacoelomorpha, and could form the Xenambulacraria group.[13][14][15]

Notable characteristics

edit
 
Early development differences between deuterostomes versus protostomes. In deuterostomes, blastula divisions occur as radial cleavage because they occur parallel or perpendicular to the major polar axis. In protostomes the cleavage is spiral because division planes are oriented obliquely to the polar major axis. During gastrulation, deuterostome embryos' anus is given first by the blastopore while the mouth is formed secondarily, and vice versa for the protostomes

In both deuterostomes and protostomes, a zygote first develops into a hollow ball of cells, called a blastula. In deuterostomes, the early divisions occur parallel or perpendicular to the polar axis. This is called radial cleavage, and also occurs in certain protostomes, such as the lophophorates.

Most deuterostomes display indeterminate cleavage, in which the developmental fate of the cells in the developing embryo is not determined by the identity of the parent cell. Thus, if the first four cells are separated, each can develop into a complete small larva; and if a cell is removed from the blastula, the other cells will compensate. This is the source of identical twins.

In deuterostomes the mesoderm forms as evaginations of the developed gut that pinch off to form the coelom. This process is called enterocoely.

Another feature present in both the Hemichordata and Chordata is pharyngotremy — the presence of spiracles or gill slits into the pharynx, which is also found in some primitive fossil echinoderms (mitrates).[16][17]

A hollow nerve cord is found in all chordates, including tunicates (in the larval stage). Some hemichordates also have a tubular nerve cord. In the early embryonic stage, it looks like the hollow nerve cord of chordates.

Both the hemichordates and the chordates have a thickening of the aorta, homologous to the chordate heart, which contracts to pump blood. This suggests a presence in the deuterostome ancestor of the three groups, with the echinoderms having secondarily lost it.[citation needed]

The highly modified nervous system of echinoderms obscures much about their ancestry, but several facts suggest that all present deuterostomes evolved from a common ancestor that had pharyngeal gill slits, a hollow nerve cord, circular and longitudinal muscles and a segmented body.[18]

Formation of mouth and anus

edit
Main article: Embryological origins of the mouth and anus

The defining characteristic of the deuterostome is the fact that the blastopore (the opening at the bottom of the forming gastrula) becomes the anus, whereas in protostomes the blastopore becomes the mouth. The deuterostome mouth develops at the opposite end of the embryo, from the blastopore, and a digestive tract develops in the middle, connecting the two.

In many animals, these early development stages later evolved in ways that no longer reflect these original patterns. For instance, humans have already formed a gut tube at the time of formation of the mouth and anus. Then the mouth forms first[citation needed], during the fourth week of development, and the anus forms four weeks later, temporarily forming a cloaca.

Origins and evolution

edit
 

Bilateria, one of the five major lineages of animals, is split into two groups; the protostomes and deuterostomes. Deuterostomes consist of chordates (which include the vertebrates) and ambulacrarians.[19] It seems likely that the 555 million year old Kimberella was a member of the protostomes.[20][21] That implies that the protostome and deuterostome lineages split long before Kimberella appeared, and hence well before the start of the Cambrian 538.8 million years ago,[19] i.e. during the earlier part of the Ediacaran Period (circa 635-539 Mya, around the end of global Marinoan glaciation in the late Neoproterozoic). It has been proposed that the ancestral deuterostome, before the chordate/ambulacrarian split, could have been a chordate-like animal with a terminal anus and pharyngeal openings but no gill slits, with active suspension feeding strategy.[22]

The last common ancestor of the deuterostomes had lost all innexin diversity.[23]

Fossil record

edit

Deuterostomes have a rich fossil record with thousands of fossil species being found throughout the Phanerozoic. There are also a few earlier fossils that may represent deuterostomes, but these remain debated. The earliest of these disputed fossils are the tunicate-like organisms Burykhia and Ausia from the Ediacaran period. While these may in fact be tunicates, others have interpreted them as cnidarians[24] or sponges,[25] and as such their true affinity remains uncertain. Another Ediacaran fossil, Arkarua, may represent the earliest echinoderm, while Yanjiahella from the early Cambrian (Fortunian) period is another notable stem group echinoderm.[26][27]

Fossils of one major deuterostome group, the echinoderms (whose modern members include sea stars, sea urchins and crinoids), are quite common from the start of Stage 3 of the Cambrian, 521 million years ago[28] starting with forms such as Helicoplacus. Two other Cambrian Stage 3 (521-514 mya) species, Haikouichthys and Myllokunmingia from the Chengjiang biota, are the earliest bodyfossils of fish,[29][30] whereas Pikaia, discovered much earlier but from the Mid Cambrian Burgess Shale, is now regarded as a primitive chordate.[31] The Mid Cambrian fossil Rhabdotubus johanssoni has been interpreted as a pterobranch hemichordate,[32] whereas Spartobranchus is an acorn-worm from the Burgess Shale, providing proof that all main lineages were already well established 508 mya.

On the other hand, fossils of early chordates are very rare, as non-vertebrate chordates have no bone tissue or teeth, and fossils of no Post-Cambrian non-vertebrate chordates are known aside from the Permian-aged Paleobranchiostoma, trace fossils of the Ordovician colonial tunicate Catellocaula, and various Jurassic-aged and Tertiary-aged spicules tentatively attributed to ascidians.[citation needed]. Fossils of Echinodermata remain very common after the Cambrian. Fossils of Hemichordata are less common, except for graptolites until the Lower-Carbonoferous.

Phylogeny

edit

Below is a phylogenetic tree showing consensus relationships among deuterostome taxa. Phylogenomic evidence suggests the enteropneust family, Torquaratoridae, fall within the Ptychoderidae. The tree is based on 16S +18S rRNA sequence data and phylogenomic studies from multiple sources.[33][34] The approximate dates for each radiation into a new clade are given in millions of years ago (Mya). Not all dates are consistent, as of date ranges only the center is given.[35]


Nephrozoa

Support for the clade Deuterostomia is not unequivocal. In particular, the Ambulacraria are sometimes shown to be related to the Xenacoelomorpha. If true, this raises two possibilities: either the Ambulacraria are taken out of the deuterostome-protostome dichotomy (in which case the grouping Deuterostomia dissolves, with Chordata and Protostomia grouped together as Centroneuralia), or the Xenacoelomorpha are re-positioned next to Ambulacraria within the Deuterostomia as in the above diagram.[34][36][37][38][39][40][41][42]

Notes

edit
  1. ^ Often considered part of Enteropneusta

References

edit
  1. ^ Fedonkin, M. A.; Vickers-Rich, P.; Swalla, B. J.; Trusler, P.; Hall, M. (2012). "A new metazoan from the Vendian of the White Sea, Russia, with possible affinities to the ascidians". Paleontological Journal. 46 (1): 1–11. Bibcode:2012PalJ...46....1F. doi:10.1134/S0031030112010042. S2CID 128415270.
  2. ^ Han, Jian; Morris, Simon Conway; Ou, Qiang; Shu, Degan; Huang, Hai (2017). "Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China)". Nature. 542 (7640): 228–231. Bibcode:2017Natur.542..228H. doi:10.1038/nature21072. PMID 28135722. S2CID 353780.
  3. ^ Wade, Nicholas (30 January 2017). "This Prehistoric Human Ancestor Was All Mouth". The New York Times. Retrieved 31 January 2017.
  4. ^ Han, Jian; Morris, Simon Conway; Ou, Qiang; Shu, Degan; Huang, Hai (2017). "Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China)". Nature. 542 (7640): 228–231. Bibcode:2017Natur.542..228H. doi:10.1038/nature21072. ISSN 0028-0836. PMID 28135722. S2CID 353780.
  5. ^ Martín-Durán, José M.; Passamaneck, Yale J.; Martindale, Mark Q.; Hejnol, Andreas (2016). "The developmental basis for the recurrent evolution of deuterostomy and protostomy". Nature Ecology & Evolution. 1 (1): 0005. Bibcode:2016NatEE...1....5M. doi:10.1038/s41559-016-0005. PMID 28812551. S2CID 90795.
  6. ^ a b Eernisse, Douglas J.; Albert, James S.; Anderson, Frank E. (1992-09-01). "Annelida and Arthropoda are Not Sister Taxa: A Phylogenetic Analysis of Spiralian Metazoan Morphology". Systematic Biology. 41 (3): 305–330. doi:10.1093/sysbio/41.3.305. ISSN 1063-5157.
  7. ^ Nielsen, C. (July 2002). "The Phylogenetic Position of Entoprocta, Ectoprocta, Phoronida, and Brachiopoda". Integrative and Comparative Biology. 42 (3): 685–691. doi:10.1093/icb/42.3.685. PMID 21708765.
  8. ^ a b Brusca, R.C.; Brusca, G.J. (1990). Invertebrates. Sinauer Associates. p. 669.
  9. ^ Halanych, K.M.; Bacheller, J.; Liva, S.; Aguinaldo, A. A.; Hillis, D.M. & Lake, J.A. (17 March 1995). "18S rDNA evidence that the Lophophorates are Protostome Animals". Science. 267 (5204): 1641–1643. Bibcode:1995Sci...267.1641H. doi:10.1126/science.7886451. PMID 7886451. S2CID 12196991.
  10. ^ Marlétaz, Ferdinand; Martin, Elise; Perez, Yvan; Papillon, Daniel; Caubit, Xavier; Lowe, Christopher J.; Freeman, Bob; Fasano, Laurent; Dossat, Carole; Wincker, Patrick; Weissenbach, Jean (2006-08-01). "Chaetognath phylogenomics: a protostome with deuterostome-like development". Current Biology. 16 (15): R577–R578. Bibcode:2006CBio...16.R577M. doi:10.1016/j.cub.2006.07.016. PMID 16890510. S2CID 18339954.
  11. ^ Marlétaz, Ferdinand; Peijnenburg, Katja T.C.A.; Goto, Taichiro; Satoh, Noriyuki; Rokhsar, Daniel S. (2019-01-21). "A New Spiralian Phylogeny Places the Enigmatic Arrow Worms among Gnathiferans". Current Biology. 29 (2): 312–318.e3. Bibcode:2019CBio...29E.312M. doi:10.1016/j.cub.2018.11.042. PMID 30639106.
  12. ^ Acorn worm genome reveals gill origins of human pharynx | Berkeley News
  13. ^ Bourlat, Sarah J.; Juliusdottir, Thorhildur; Lowe, Christopher J.; Freeman, Robert; Aronowicz, Jochanan; Kirschner, Mark; Lander, Eric S.; Thorndyke, Michael; Nakano, Hiroaki; Kohn, Andrea B.; Heyland, Andreas; Moroz, Leonid L.; Copley, Richard R.; Telford, Maximilian J. (2006). "Deuterostome phylogeny reveals monophyletic chordates and the new phylum Xenoturbellida". Nature. 444 (7115): 85–88. Bibcode:2006Natur.444...85B. doi:10.1038/nature05241. ISSN 0028-0836. PMID 17051155. S2CID 4366885.
  14. ^ Philippe, Hervé; Poustka, Albert J.; Chiodin, Marta; Hoff, Katharina J.; Dessimoz, Christophe; Tomiczek, Bartlomiej; Schiffer, Philipp H.; Müller, Steven; Domman, Daryl; Horn, Matthias; Kuhl, Heiner; Timmermann, Bernd; Satoh, Noriyuki; Hikosaka-Katayama, Tomoe; Nakano, Hiroaki; Rowe, Matthew L.; Elphick, Maurice R.; Thomas-Chollier, Morgane; Hankeln, Thomas; Mertes, Florian; Wallberg, Andreas; Rast, Jonathan P.; Copley, Richard R.; Martinez, Pedro; Telford, Maximilian J. (2019). "Mitigating Anticipated Effects of Systematic Errors Supports Sister-Group Relationship between Xenacoelomorpha and Ambulacraria". Current Biology. 29 (11): 1818–1826.e6. Bibcode:2019CBio...29E1818P. doi:10.1016/j.cub.2019.04.009. hdl:21.11116/0000-0004-DC4B-1. ISSN 0960-9822. PMID 31104936. S2CID 155104811.
  15. ^ Marlétaz, Ferdinand (2019-06-17). "Zoology: Worming into the Origin of Bilaterians". Current Biology. 29 (12): R577–R579. Bibcode:2019CBio...29.R577M. doi:10.1016/j.cub.2019.05.006. ISSN 0960-9822. PMID 31211978.
  16. ^ Graham, A; Richardson, J (2012). "Developmental and evolutionary origins of the pharyngeal apparatus". Evodevo. 3 (1): 24. doi:10.1186/2041-9139-3-24. PMC 3564725. PMID 23020903.
  17. ^ Valentine, James W. (June 18, 2004). On the Origin of Phyla. University of Chicago Press. ISBN 978-0-226-84548-7 – via Google Books.
  18. ^ Smith, Andrew B. (2012). "Cambrian problematica and the diversification of deuterostomes". BMC Biology. 10 (79): 79. doi:10.1186/1741-7007-10-79. PMC 3462677. PMID 23031503.
  19. ^ a b Erwin, Douglas H.; Eric H. Davidson (1 July 2002). "The last common bilaterian ancestor". Development. 129 (13): 3021–3032. doi:10.1242/dev.129.13.3021. PMID 12070079.
  20. ^ Fedonkin, M.A.; Simonetta, A; Ivantsov, A.Y. (2007), "New data on Kimberella, the Vendian mollusc-like organism (White sea region, Russia): palaeoecological and evolutionary implications", in Vickers-Rich, Patricia; Komarower, Patricia (eds.), The Rise and Fall of the Ediacaran Biota, Special publications, vol. 286, London: Geological Society, pp. 157–179, doi:10.1144/SP286.12, ISBN 978-1-86239-233-5, OCLC 156823511
  21. ^ Butterfield, N.J. (December 2006). "Hooking some stem-group "worms": fossil lophotrochozoans in the Burgess Shale". BioEssays. 28 (12): 1161–1166. doi:10.1002/bies.20507. PMID 17120226. S2CID 29130876.
  22. ^ 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. Bibcode:2023CBio...33E2359L. doi:10.1016/j.cub.2023.04.048. PMID 37167976.
  23. ^ Connexins evolved after early chordates lost innexin diversity
  24. ^ Hahn, G; Pflug, H. D (1985). "Polypenartige Organismen aus dem Jung-Präkambrium (Nama-Gruppe) von Namibia". Pascal-Francis (19): 1–13. Retrieved 13 March 2024.
  25. ^ M. A. Fedonkin (1996). "Ausia as an ancestor of archeocyathans, and other sponge-like organisms". In: Enigmatic Organisms in Phylogeny and Evolution. Abstracts. Moscow, Paleontological Institute, Russian Academy of Sciences, p. 90-91.
  26. ^ Cracknell, Kelsie; García-Bellido, Diego C.; Gehling, James G.; Ankor, Martin J.; Darroch, Simon A. F.; Rahman, Imran A. (2021-02-18). "Pentaradial eukaryote suggests expansion of suspension feeding in White Sea-aged Ediacaran communities". Scientific Reports. 11 (1): 4121. Bibcode:2021NatSR..11.4121C. doi:10.1038/s41598-021-83452-1. ISSN 2045-2322. PMC 7893023. PMID 33602958.
  27. ^ Zamora, Samuel; Wright, David F.; Mooi, Rich; Lefebvre, Bertrand; Guensburg, Thomas E.; Gorzelak, Przemysław; David, Bruno; Sumrall, Colin D.; Cole, Selina R.; Hunter, Aaron W.; Sprinkle, James; Thompson, Jeffrey R.; Ewin, Timothy A. M.; Fatka, Oldřich; Nardin, Elise (2020-03-09). "Re-evaluating the phylogenetic position of the enigmatic early Cambrian deuterostome Yanjiahella". Nature Communications. 11 (1): 1286. Bibcode:2020NatCo..11.1286Z. doi:10.1038/s41467-020-14920-x. ISSN 2041-1723. PMC 7063041. PMID 32152310.
  28. ^ Bengtson, S. (2004). Lipps, J.H.; Waggoner, B.M. (eds.). "Early Skeletal Fossils in Neoproterozoic–Cambrian Biological Revolutions" (PDF). Paleontological Society Papers. 10: 67–78. doi:10.1017/S1089332600002345. Archived from the original (PDF) on 2008-10-03. Retrieved 2015-09-01.
  29. ^ Shu, D.-G.; Conway Morris, S.; Han, J.; et al. (January 2003). "Head and backbone of the Early Cambrian vertebrate Haikouichthys". Nature. 421 (6922): 526–529. Bibcode:2003Natur.421..526S. doi:10.1038/nature01264. PMID 12556891. S2CID 4401274.
  30. ^ Shu, D.-G.; Conway Morris, S. & Zhang, X.-L. (November 1999). "Lower Cambrian vertebrates from south China". Nature. 402 (6757): 42–46. Bibcode:1999Natur.402...42S. doi:10.1038/46965. S2CID 4402854.
  31. ^ Shu, D.-G.; Conway Morris, S. & Zhang, X.-L. (November 1996). "A Pikaia-like chordate from the Lower Cambrian of China". Nature. 384 (6605): 157–158. Bibcode:1996Natur.384..157S. doi:10.1038/384157a0. S2CID 4234408.
  32. ^ Bengtson, S.; Urbanek, A. (October 2007). "Rhabdotubus, a Middle Cambrian rhabdopleurid hemichordate". Lethaia. 19 (4): 293–308. doi:10.1111/j.1502-3931.1986.tb00743.x.
  33. ^ Tassia, Michael G.; Cannon, Johanna T.; Konikoff, Charlotte E.; Shenkar, Noa; Halanych, Kenneth M.; Swalla, Billie J. (2016-10-04). "The Global Diversity of Hemichordata". PLOS ONE. 11 (10): e0162564. Bibcode:2016PLoSO..1162564T. doi:10.1371/journal.pone.0162564. PMC 5049775. PMID 27701429.
  34. ^ a b Kapli, Paschalia; Natsidis, Paschalis; Leite, Daniel J.; Fursman, Maximilian; Jeffrie, Nadia; Rahman, Imran A.; Philippe, Hervé; Copley, Richard R.; Telford, Maximilian J. (March 1, 2021). "Lack of support for Deuterostomia prompts reinterpretation of the first Bilateria". Science Advances. 7 (12): eabe2741. Bibcode:2021SciA....7.2741K. doi:10.1126/sciadv.abe2741. PMC 7978419. PMID 33741592.
  35. ^ Han, Jian; Morris, Simon Conway; Ou, Qian; Shu, Degan; Huang, Hai (2017). "Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China)". Nature. 542 (7640): 228–231. Bibcode:2017Natur.542..228H. doi:10.1038/nature21072. PMID 28135722. S2CID 353780.
  36. ^ Philippe, Hervé; Poustka, Albert J.; Chiodin, Marta; Hoff, Katharina J.; Dessimoz, Christophe; Tomiczek, Bartlomiej; Schiffer, Philipp H.; Müller, Steven; Domman, Daryl; Horn, Matthias; Kuhl, Heiner (2019-06-03). "Mitigating Anticipated Effects of Systematic Errors Supports Sister-Group Relationship between Xenacoelomorpha and Ambulacraria". Current Biology. 29 (11): 1818–1826.e6. Bibcode:2019CBio...29E1818P. doi:10.1016/j.cub.2019.04.009. hdl:21.11116/0000-0004-DC4B-1. ISSN 0960-9822. PMID 31104936.
  37. ^ Robertson, Helen E.; Lapraz, François; Egger, Bernhard; Telford, Maximilian J.; Schiffer, Philipp H. (2017-05-12). "The mitochondrial genomes of the acoelomorph worms Paratomella rubra, Isodiametra pulchra and Archaphanostoma ylvae". Scientific Reports. 7 (1): 1847. Bibcode:2017NatSR...7.1847R. doi:10.1038/s41598-017-01608-4. ISSN 2045-2322. PMC 5431833. PMID 28500313.
  38. ^ Philippe, Hervé; Brinkmann, Henner; Copley, Richard R.; Moroz, Leonid L.; Nakano, Hiroaki; Poustka, Albert J.; Wallberg, Andreas; Peterson, Kevin J.; Telford, Maximilian J. (2011-02-10). "Acoelomorph flatworms are deuterostomes related to Xenoturbella". Nature. 470 (7333): 255–258. Bibcode:2011Natur.470..255P. doi:10.1038/nature09676. ISSN 0028-0836. PMC 4025995. PMID 21307940.
  39. ^ Edgecombe, Gregory D.; Giribet, Gonzalo; Dunn, Casey W.; Hejnol, Andreas; Kristensen, Reinhardt M.; Neves, Ricardo C.; Rouse, Greg W.; Worsaae, Katrine; Sørensen, Martin V. (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. S2CID 32169826.
  40. ^ 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. Bibcode:2016Natur.530...94R. doi:10.1038/nature16545. PMID 26842060. S2CID 3870574.
  41. ^ Cannon, Johanna Taylor; Vellutini, Bruno Cossermelli; Smith III, Julian; Ronquist, Frederik; Jondelius, Ulf; Hejnol, Andreas (4 February 2016). "Xenacoelomorpha is the sister group to Nephrozoa". Nature. 530 (2): 89–93. Bibcode:2016Natur.530...89C. doi:10.1038/nature16520. PMID 26842059. S2CID 205247296.
  42. ^ Paschalia Kapli; Maximilian J. Telford (11 December 2020). "Topology-dependent asymmetry in systematic errors affects phylogenetic placement of Ctenophora and Xenacoelomorpha". Science Advances. 6 (50): eabc5162. Bibcode:2020SciA....6.5162K. doi:10.1126/sciadv.abc5162. PMC 7732190. PMID 33310849.

Further reading

edit
edit
 
Wikispecies has information related to Deuterostomia.
 
Wikimedia Commons has media related to Deuterostomia.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Deuterostome&oldid=1257158496"
  NODES
HOME 1
Idea 9
idea 9
iOS 1
languages 1
Note 3
os 140