Editing Hagfish (section)

==Phylogeny==
Hagfish are in the group [[Cyclostomata]] which includes jawless fish. The group [[Cyclostomata]] is characterized by two significant characteristics; [[keratin]]ous tooth plates and movement of postotic [[myomere]]s to the orbitals.<ref name=":1">{{Cite journal|last1=Miyashita|first1=Tetsuto|last2=Coates|first2=Michael I.|last3=Farrar|first3=Robert|last4=Larson|first4=Peter|last5=Manning|first5=Phillip L.|last6=Wogelius|first6=Roy A.|last7=Edwards|first7=Nicholas P.|last8=Anné|first8=Jennifer|last9=Bergmann|first9=Uwe|last10=Palmer|first10=A. Richard|last11=Currie|first11=Philip J.|date=2019-02-05|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|language=en|volume=116|issue=6|pages=2146–2151|doi=10.1073/pnas.1814794116|issn=0027-8424|pmc=6369785|pmid=30670644|bibcode=2019PNAS..116.2146M|doi-access=free}}</ref> According to fossil record, hagfish and [[lamprey]]s have been estimated to have diverged from one another during the [[Paleozoic]] period.<ref name=":1"/> An experiment used an estimation of synonymous and nonsynonymous substitutions for [[nucleotide]]s and supplemented that data with pre-existing data into a clock that would calculate divergence times for the [[taxon]]s ''[[Myxine]]'' and ''[[Eptatretus]]''.<ref name="Kuraku">{{cite journal |last1=Kuraku |first1=S. |last2=Kuratani |first2=S. |year=2006 |title=Time scale for cyclostome evolution inferred with a phylogenetic diagnosis of hagfish and lamprey cDNA sequences |journal=Zoological Science |volume=23 |issue=12 |pages=1053–1064 |doi=10.2108/zsj.23.1053 |pmid=17261918 |s2cid=7354005|doi-access=free }}</ref> This data found that the lineage diverged around 93–28 Mya; however, later studies have found even earlier divergence times within the group, with ''Myxine'' and ''Eptatretus'' diverging during the Triassic and the ancestor of  ''[[Rubicundus]]'' diverging during other extant hagfishes during the [[Permian]].<ref name="Kuraku"/><ref>{{Cite journal |last1=Brownstein |first1=Chase Doran |last2=Near |first2=Thomas |date=2024-06-13 |title=Colonization of the ocean floor by jawless vertebrates across three mass extinctions |journal=BMC Ecology and Evolution |volume=24 |issue=1 |pages=79 |doi=10.1186/s12862-024-02253-y |doi-access=free |issn=2730-7182 |pmc=11170801 |pmid=38867201|bibcode=2024BMCEE..24...79B }}</ref> Hagfish are excluded from the subphylum [[Gnathostomata]] because of [[Morphology (biology)|morphological]] characteristics including the hagfish arched tongue.<ref name=":4"/> Hagfish embryos have characteristics of gnathostomes and may be plesiomorphic;<ref name=":4"/> however, these characteristics drastically change [[Morphology (biology)|morphologically]] as the hagfish matures.<ref name=":4"/> The following hagfish and lamprey phylogeny is an adaptation based on the 2019 work of Miyashita et al.<ref>{{Cite journal |last1=Miyashita |first1=Tetsuto |last2=Coates |first2=Michael I. |last3=Farrar |first3=Robert |last4=Larson |first4=Peter |last5=Manning |first5=Phillip L. |last6=Wogelius |first6=Roy A. |last7=Edwards |first7=Nicholas P. |last8=Anné |first8=Jennifer |last9=Bergmann |first9=Uwe |last10=Palmer |first10=A. Richard |last11=Currie |first11=Philip J. |date=2019-02-05 |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 |language=en |volume=116 |issue=6 |pages=2146–2151 |doi=10.1073/pnas.1814794116 |issn=0027-8424 |pmc=6369785 |pmid=30670644|bibcode=2019PNAS..116.2146M |doi-access=free }}</ref>

{{Clade|{{Clade
   |1=†''[[Haikouella]]''
   |2={{Clade
      |1={{Clade
         |1=†''[[Haikouichthys]]''
         |2=†''[[Myllokunmingia]]''
         }}
      |2={{Clade
         |1=†''[[Metaspriggina]]''
         |label2=[[Vertebrata]]|sublabel2=(crown group)
         |2={{Clade
            |1=[[Gnathostomata]] (jawed fish)
            |2={{Clade
               |label1=†[[Anaspida]]
               |1={{Clade
                  |1=†''[[Cornovichthys]]''
                  |2={{Clade
                     |1={{Clade
                        |1=†''[[Achanarella]]''
                        |2=†''[[Ciderius]]''
                        }}
                     |2={{Clade
                        |1=†[[Birkeniida]]
                        |2={{Clade
                           |1=†''[[Lasanius]]''
                           |2={{Clade
                              |1=†''[[Euphanerops]]''
                              |2=†''[[Jamoytius]]''
                  }} }} }} }} }}
               |2={{Clade
                  |1=†''[[Pipiscius]]''
                  |2={{Clade
                     |1=†[[conodont|Conodonta]] (conodonts)
                     |label2=[[Cyclostomi]]|sublabel2=(crown group)
                     |2={{Clade
                        |1={{Clade
                           |1=†''[[Myxinikela]]''
                           |label2=[[Myxinoidea]]|sublabel2=(crown group)
                           |2={{Clade
                              |1={{Clade
                                 |1=†''[[Tethymyxine tapirostrum]]''
                                 |2={{Clade
                                    |1=''[[Rubicundus eos]]''
                                    |2=''[[Rubicundus lopheliae]]''
                                 }} }}
                              |2={{Clade
                                 |1={{Clade
                                    |1=''[[Myxine glutinosa]]''
                                    |2=''[[Neomyxine biniplicata]]''
                                    }}
                                 |2={{Clade
                                    |1=''[[Eptatretus stoutii]]''
                                    |2={{Clade
                                       |1=''[[Eptatretus burgeri]]''
                                       |2="''[[Paramyxine]]''" spp.
                           }} }} }} }} }}
                        |2={{Clade
                           |1=†''[[Gilpichthys]]''
                           |2={{Clade
                              |1={{Clade
                                 |1=†''[[Hardistiella]]''
                                 |2=†''[[Mayomyzon]]''
                                 }}
                              |2={{Clade
                                 |1=†''[[Myxineidus]]''
                                 |2={{Clade
                                    |1=†''[[Priscomyzon]]''
                                    |2={{Clade
                                       |1=†''[[Mesomyzon]]''
                                       |label2=[[Petromyzontiformes]]|sublabel2=(crown group)
                                       |2={{Clade
                                          |1={{Clade
                                             |1=''[[Geotria australis]]''
                                             |2=''[[Mordacia mordax]]''
                                             }}
                                          |2={{Clade
                                             |1=''[[Petromyzon marinus]]''
                                             |2={{Clade
                                                |1=''[[Lampetra fluviatilis]]''
                                                |2=''[[Lethenteron camtschaticum]]''
}} }} }} }} }} }} }} }} }} }} }} }} }} }} }} }}|style=font-size:85%; line-height:85%}}