After Shu et al., 2003, and Janvier, 2015

<==o Chordata Haeckel, 1874 (chordates; selkäjänteiset)
   |-- Cephalochordata Haeckel, 1866 (kallottomat selkäjänteiset)
   `--o Olfactores Jefferies, 1991 sensu Delsuc, Brickmann, Chourrout & Philippe, 2006
      |-- Tunicata Lamarck, 1816 [Urochordata Lankester 1877] (tunicates; vaippaeläimet)
      `--o Vertebrata Lamarck, 1801 [Craniata Lankester, 1877] (vertebrates; selkärankaiset)
         |?- †Myllokunmingia fengjiaoa Shu, Zhang & Han, 1999 [=? Haikouichthys ercaicunensis sensu Zhang & Hou, 2004]
         |?- †Haikouichthys ercaicunensis Luo, Hu & Shu, 1999 sensu Shu et al., 2003
         |--o Cyclostomata Duméril, 1806 (“round mouths”; ympyräsuiset)
         |  |?- †Conodonta Eichenberg, 1930 sensu Sweet & Donoghue, 2001 [Conodontia, Euconodonta, Conodontophorida] (conodonts; konodontit)
         |  `--+--o Hyperotreti
         |     |  `-- Myxini (hagfishes; limaajat, limanahkiaiset)
         |     `-- Hyperoartii Müller, 1844 [Hyperoartia] (lampreys; nahkiaiskalat)
         `--o “Gnathostomatomorpha” [paraphyletic Ostracodermi]
            |-- †Pteraspidomorphi Goodrich, 1909 [Diplorhina] (“kaksisieraimiset”)
            `--+-- †Anaspida Traquair, 1899
               `--+?=Thelodonti Jaekel, 1911 [Thelodontomorphi Jaekel, 1911] [paraphyletic??]
                  |?- †Furcacaudiformes Wilson & Caldwell, 1998 (“fork-tailed thelodonts”)
                  `--+-- †Galeaspida Liu, 1965 [non Tarlo, 1967]
                     `--+--o †Pituriaspida
                        |  |-- †Pituriaspis doylei
                        |  `-- †Neeyambaspis enigmatica
                        |-- †Osteostraci Lankester, 1868 [Cephalaspidiformes]
                        `--+?- †Eleochera glossa Sansom & Smith, 2005
                           `-- Gnathostomata Gegenbaur, 1874 (jawed vertebrates; leualliset selkärankaiset)

After McCoy, Saupe, Lamsdell, Tarhan, McMahon, Lidgard, Mayer, Whalen, Soriano, Finney, Vogt, Clark, Anderson, Petermann, Locatelli & Briggs, 2016

<==o Chordata
   |-- Cephalochordata
   `--+-- Tunicata
      `--+-- †Pikaia
         `--o Vertebrata
            |-- †Myllokunmingia
            |-- †Haikouichthys
            |-- †Metaspriggina
            |-- †Euconodonta
            |--o Hyperotreti
            |  |-- †Gilpichthys
            |  `--+-- †Myxinikela
            |     `-- Myxinoidea
            |--o Hyperoartii
            |  |-- †Mayomyzon
            |  `--+-- †Tullimonstrum
            |     `--+-- †Pipiscius
            |        |-- †Priscomyzon
            |        `--+-- †Mesomyzon
            |           `--o Petromyzontida
            |              `-- Petromyzontidae
            `--o “Gnathostomatomorpha”
               |-- †Jamoytius
               |-- †Euphanerops
               `--+-- †Anaspida
                  `--+--o †Thelodonti
                     |  |-- †Turinia
                     |  `-- †Loganellia
                     `--+-- †Pteraspidomorphi
                        `--+-- †Galeaspida
                           `--+-- †Osteostraci
                              `-- Gnathostomata

Reference(s):

  • McCoy, V. E., Saupe, E. E., Lamsdell, J. C., Tarhan, L. G., McMahon, S., Lidgard, S., Mayer, P., Whalen, C. D., Soriano, C., Finney, L., Vogt, S., Clark, E. G., Anderson, R. P., Petermann, H., Locatelli, E. R. & Briggs, D. E. G., 2016: The ‘Tully monster’ is a vertebrate.
    –Nature: in press [doi: 10.1038/nature16992]

After Delsuc, Brickmann, Chourrout & Philippe, 2006

<==o Chordata
   |-- Cephalochordata
   `--o Olfactores
      |-- Urochordata
      `--o Craniata
         |-- Myxini
         `-- Vertebrata

Reference8s):

  • Delsuc, F., Brickmann, H., Chourrout, D. & Philippe, H., 2006: Tunicates and not cephalochordates are the closest living relatives of vertebrates.
    –Nature: Vol. 439, pp. 965-968 [doi: 10.1038/nature04336]

After Janvier, 1997 ["The Tree of Life"]

<==o Chordata
   |?- Urochordata
   `--+-- Cephalochordata
      `--o Craniata
         |-- Myxini
         `-- Vertebrata

Reference(s):