Editing Craniate (section)

{{Short description|Clade of chordates, member of the Craniata}}
{{Redirect|Craniata|a [[Class (biology)|class]] of [[Brachiopoda|Brachiopod]]|Craniforma}}{{For|an explanation of its other name|Vertebrate}}{{Automatic taxobox
| fossil_range = <br>[[Cambrian Stage 3]]&ndash;[[Holocene|Present]],<br>{{fossil range|518|0|earliest= 525|ref=<ref name="Yang2018">{{Cite journal|last1=Yang|first1=Chuan|last2=Li|first2=Xian-Hua|last3=Zhu|first3=Maoyan|last4=Condon|first4=Daniel J.|last5=Chen|first5=Junyuan|date=2018|title=Geochronological constraint on the Cambrian Chengjiang biota, South China|journal=Journal of the Geological Society|language=en|volume=175|issue=4|pages=659–666|doi=10.1144/jgs2017-103|bibcode=2018JGSoc.175..659Y|s2cid=135091168|issn=0016-7649|url=http://nora.nerc.ac.uk/id/eprint/521412/1/2018-JGS-Chuan%20Yang%20et%20al.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://nora.nerc.ac.uk/id/eprint/521412/1/2018-JGS-Chuan%20Yang%20et%20al.pdf |archive-date=2022-10-09 |url-status=live}}</ref>}}
| name = Craniates
| image = Pacific hagfish Myxine.jpg
| image_caption = A [[Pacific hagfish]], an example of (what was thought to be) a "non-vertebrate craniate"
| taxon = Craniata
| authority = Lankester, 1877<ref name="Nielsen2012">{{Cite journal
   | title = The authorship of higher chordate taxa
   | author = Nielsen, C.
   | journal = Zoologica Scripta
   | volume = 41 | issue = 4 | pages = 435–436
   | date = July 2012
   | doi = 10.1111/j.1463-6409.2012.00536.x
 | s2cid = 83266247
 }}</ref>
| subdivision_ranks = Included groups
| subdivision = *[[Agnatha]]
** [[Hyperoartia]] ([[lamprey]]s) {{small|(disputed vertebrates)}}
** [[Myxini]] (hagfishes)
** [[Cephalaspidomorphi]] {{small|(possible vertebrates)}}
*** [[Gnathostomata]] {{small|(emerged from within Cephalaspidomorphi)}}<ref>{{Cite journal|last=Miyashita|first=Tetsuto|date=2019|title=Hagfish from the Cretaceous Tethys Sea and a reconciliation of the morphological–molecular conflict in early vertebrate phylogeny|journal=Proceedings of the National Academy of Sciences of the United States of America|volume=116|issue=6|pages=2146–2151|doi=10.1073/pnas.1814794116|pmid=30670644|pmc=6369785|bibcode=2019PNAS..116.2146M|doi-access=free}}</ref>
| synonyms = *   Craniota {{small|Haeckel, 1866}}
*   Pachycardia {{small|Haeckel, 1866}}
*   [[Vertebrata]] {{small|J-B. Lamarck, 1801}}
}}

A '''craniate''' is a member of the '''Craniata''' (sometimes called the '''Craniota'''), a proposed [[clade]] of [[chordate]] [[animal]]s with a [[skull]] of hard [[bone]] or [[cartilage]]. Living representatives are the [[Myxini]] (hagfishes), [[Hyperoartia]] (including [[lamprey]]s), and the much more numerous [[Gnathostomata]] (jawed vertebrates).<ref name="Campbell & Reece 2005 p. 676">Campbell & Reece 2005 p. 676</ref><ref>Cracraft & Donoghue 2004 p. 390</ref> Formerly distinct from [[vertebrate]]s, which excluded [[hagfish]], however molecular and anatomical research in the 21st century has led to the reinclusion of hagfish as vertebrates, making living craniates synonymous with living vertebrates.

The clade was conceived largely on the basis of the Hyperoartia (lampreys and kin) being more closely related to the Gnathostomata (jawed vertebrates) than the Myxini (hagfishes). This, combined with an apparent lack of vertebral elements within the Myxini, suggested that the Myxini were descended from a more ancient lineage than the vertebrates, and that the skull developed before the [[vertebral column]]. The clade was thus composed of the Myxini and the [[vertebrate]]s, and any extinct chordates with skulls.

However recent studies using [[molecular phylogenetics]] have contradicted this view, with evidence that the [[Cyclostomata]] ([[Hyperoartia]] and Myxini) is [[Monophyly|monophyletic]]; this result suggests that the Myxini are degenerate vertebrates, and therefore that vertebrates and craniates are cladistically equivalent, at least for the living representatives. The placement of the Myxini within the vertebrates has been further strengthened by recent anatomical analysis, with vestiges of a vertebral column being discovered in the Myxini.<ref name="Janvier2011">{{cite journal|last1=Janvier|first1=Philippe|title=Comparative Anatomy: All Vertebrates Do Have Vertebrae|journal=Current Biology|volume=21|issue=17|year=2011|pages=R661–R663|issn=0960-9822|doi=10.1016/j.cub.2011.07.014|pmid=21920298|s2cid=17652802|doi-access=free|bibcode=2011CBio...21.R661J }}</ref>