Editing Vertebrate (section)

=== External phylogeny ===

The closest relatives of vertebrates have been debated over the years. It was once thought that the [[Cephalochordata]] was the [[sister taxon]] to Vertebrata. This group, Notochordata, was taken to be sister to the [[Tunicata]].<ref>{{cite journal |last=Stach |first=Thomas |title=Chordate phylogeny and evolution: a not so simple three-taxon problem |journal=[[Journal of Zoology]] |date=2008 |volume=276 |issue=2 |pages=117–141 |doi=10.1111/j.1469-7998.2008.00497.x |doi-access=free }}</ref> Since 2006, analysis has shown that the tunicates + vertebrates form a clade, the Olfactores, with Cephalochordata as its sister (the [[Olfactores#Olfactores hypothesis|Olfactores hypothesis]]), as shown in the following [[phylogenetic tree]].<ref name="Delsuc 2006">{{cite journal |last=Delsuc |first=F. |title=Tunicates and not cephalochordates are the closest living relatives of vertebrates |journal=[[Nature (journal)|Nature]] |date=2006 |volume=439 |issue=7079 |pages=965–968 |bibcode=2006Natur.439..965D |doi=10.1038/nature04336 |pmid=16495997 |s2cid=4382758 |url=https://hal.archives-ouvertes.fr/halsde-00315436/file/Delsuc-Nature06_HAL.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://hal.archives-ouvertes.fr/halsde-00315436/file/Delsuc-Nature06_HAL.pdf |archive-date=9 October 2022 |url-status=live }}</ref><ref name="Dunn 2008">{{cite journal |last=Dunn |first=C.W. |title=Broad phylogenetic sampling improves resolution of the animal tree of life |journal=[[Nature (journal)|Nature]] |volume=452 |year=2008 |issue=7188 |doi=10.1038/nature06614 |pages=745–749 |pmid=18322464 |bibcode=2008Natur.452..745D |s2cid=4397099 }}</ref><ref name="Gupta 2016" />

{{clade|style=font-size:100%
|label1=[[Chordata]]
|1={{clade
  |label1=[[Cephalochordata]]
  |1=[[Leptocardii]] (lancelets) <span style="{{MirrorH}}">[[File:Branchiostoma lanceolatum (Amphioxus lanceolatus).png|140px]]</span>
  |label2=[[Olfactores]]
  |2={{clade
    |1=[[Tunicata]] ([[sea squirt]]s, etc) [[File:Salpa scheme.png|90px]]
    |2='''Vertebrata''' [[File:Haikouichthys cropped.jpg|90px]]
     }}
  }}
}}