Clade of deuterostomes containing echinoderms and hemichordates
Ambulacraria , or Coelomopora , 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:
(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]
^ 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 ).
^ 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 .
^ 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 .