Clade of deuterostomes containing echinoderms and hemichordates
Ambulacrarians
Temporal range: Early Cambrian–Recent
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Various sea stars and sea urchins among mussel shells in the rocky intertidal zone of Kachemak Bay, southern Alaska, United States
Scientific classification
Domain:
Eukaryota
Kingdom:
Animalia
Subkingdom:
Eumetazoa
Clade:
ParaHoxozoa
Clade:
Bilateria
Clade:
Nephrozoa
Superphylum:
Deuterostomia
Clade:
Ambulacraria Metschnikoff, 1881
Phyla
Echinodermata
Hemichordata
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.
The two living clades with representative organisms are:
Hemichordata (acorn worms, Pterobranchia, and possibly graptolites)
(These together sometimes are called the lower deuterostomes.[3])
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,[4][5][6] and other authors asserting that the best choices of phylogenetic methods support the position of Xenacoelomorpha as the sister group to Ambulacraria.[7][8]
Fossil taxa that may lie on the stem lineage:
Superphylum Ambulacraria
† "Cambroernids" (informal unranked clade)[9]
Herpetogaster
Phlogites
"Eldoniids" / "Eldonioids"
^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. Bibcode:2016Natur.530...89C. doi:10.1038/nature16520. PMID 26842059. S2CID 205247296.
^Sea Cucumber Genome Imparts Insight on Genes Linked to Organ Regeneration
^Cite error: The named reference Lacalli was invoked but never defined (see the help page).
^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.
^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.
^
Herve Philippe; et al. (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. hdl:21.11116/0000-0004-DC4B-1. PMID 31104936.
^
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.
^Caron, J.; Conway Morris, S.; Shu, D. (2010). "Tentaculate fossils from the Cambrian of Canada (British Columbia) and China (Yunnan) interpreted as primitive deuterostomes". PLOS ONE. 5 (3): e9586. Bibcode:2010PLoSO...5.9586C. doi:10.1371/journal.pone.0009586. PMC 2833208. PMID 20221405.
Ambulacraria /ˌæmbjuːləˈkrɛəriə/, or Coelomopora /siːləˈmɒpərə/, is a clade of invertebrate phyla that includes echinoderms and hemichordates; a member...
Echinoderms, and together they form the clade Ambulacraria, the sister phylum of the Chordates. Chordata, Ambulacraria, and possibly Xenacoelomorpha are believed...
fish) Superclass Osteichthyes (bony fish - includes tetrapods) Clade Ambulacraria Phylum Hemichordata Class Planctosphaeroidea Class Enteropneusta (acorn...
changed considerably since 2000. A different hypothesis is that the Ambulacraria are sister to Xenacoelomorpha together forming the Xenambulacraria. The...
blood vessel. Together with the Echinoderms, the hemichordates form the Ambulacraria, which are the closest extant phylogenetic relatives of chordates. Thus...
analyses suggest that the xenacoelomorphs are instead the sister group of Ambulacraria forming the clade Xenambulacraria and that despite their simple body...
which instead posits that Xenacoelomorpha is most closely related to Ambulacraria. Which hypothesis is correct is controversial. Authors supporting the...
colleagues (2021), proposes a clade Xenambulacraria for the Xenacoelamorpha + Ambulacraria; this is either within Deuterostomia, as sister to Chordata, or the Deuterostomia...
out of Bilateria and Phylum Xenacoelomorpha is basal Phylum Chordata Ambulacraria (unranked) Phylum Hemichordata Phylum Echinodermata Phylum Cambroernida...
tornaria larvae of some Hemichordata, reflecting the descent of the Ambulacraria from a common ancestor. Barnes, Robert D. (1982). Invertebrate Zoology...
of the Xenacoelomorpha (i.e., Xenoturbella and acoelomorphs) and the Ambulacraria (i.e., echinoderms and hemichordates). If confirmed, the clade would...
Centroneuralia would be sister to Xenambulacraria (Xenacoelomorpha + Ambulacraria) at the base of Bilateria. Centroneuralia, as a proposed clade, originates...
group echinoderm from the basal Cambrian of China and the origins of Ambulacraria". Nature Communications. 10 (1): 1366. Zamora, S., Wright, D.F., Mooi...
Errors Supports Sister-Group Relationship between Xenacoelomorpha and Ambulacraria". Current Biology. 29 (11): 1818–1826.e6. doi:10.1016/j.cub.2019.04.009...
into selection of an efficient tRNA system and supports monophyly of Ambulacraria". BMC Evolutionary Biology. 11 (1): 134. doi:10.1186/1471-2148-11-134...
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