After Wu, 1994, Evans et al., 2001, Apesteguia & Novas, 2003, and Bonaparte & Sues, 2006

<==o Sphenodontida Estes, 1983 sensu Wu, 1994 [Rhynchocephalia Günther, 1867] (Sphenodontians; alkuliskot)
   |-- †Gephyrosaurus bridensis Evans, 1980 [paraphyletic Gephyrosauridae]
   `--o Sphenodontia Williston, 1925
      |?- Sphenodontia genera et species indet. [Richmond basin, Virginia, USA]
      |-- †Diphydontosaurus avonis Whiteside, 1986 [paraphyletic Gephyrosauridae]
      `--+--o †Planocephalosaurus Fraser, 1982 [paraphyletic Gephyrosauridae]
         |  |-- †P. robinsonae Fraser, 1982
         |  `-- †P. lucasi Heckert, 2004
         |--o †Pleurosauridae Lydekker, 1888
         |  |-- †Palaeopleurosaurus posidonae Carroll, 1985
         |  `--o †Pleurosaurus Meyer
         |     |-- †P. goldfussi
         |     `-- †P. ginsburgi
         `--o Sphenodontidae Cope, 1896 [1870] sensu lato (sphenodontids, tuataras; tuatarat)
            |-- †Rebbanasaurus jaini Evans, Prasad & Manhas, 2001
            `--+--o †Clevosauridae Bonaparte & Sues, 2006 [“Clevosaurinae” sensu Wu, 1994]
               |  |-- †Polysphenodon mulleri Jaekel, 1911 [Polysphenodontinae Kuhn, 1969]
               |  `--+-- †Brachyrhinodon taylori v. Huene, 1910
               |     `--o †Clevosaurus Swinton, 1939 [Glevosaurus sensu Murry, 1987] [incl. Asiacephalosaurus; Rarojugalosaurus; Dianosaurus Young, 1982] L.Trias.-E.Jur. WEu. ENAm. EAs.
               |        |?- †C. convallis Säilä, 2005
               |        |?- †C. minor Fraser, 1988
               |        |?- †C. sp. [England] [Fraser, 1988]
               |        |?- †C.? sp. [South Africa] [Gow & Raath, 1977]
               |        |?- †C. sp. [South Africa] [Sues & Reisz, unpubl. data (Sues, Shubin & Olson, 1994)]
               |        |?- †c. brasiliensis Bonaparte & Sues, 2006
               |        `--+--+-- †C. petilus (Young, 1982) [Dianosaurus petilus Young, 1982]
               |           |  `-- †C. hudsoni Swinton, 1939
               |           `--+?- †C. wangi Wu, 1994 [Asiacephalosaurus wangi (Wu)]
               |              |-- †C. bairdi Sues, Shubin & Olsen, 1994 [was C. sp. (Sues, Shubin & Olsen)]
               |              `-- †C. mcgilli Wu, 1994 [Rarojugalosaurus mcgilli]
               `--o Sphenodontidae Cope, 1896 [1870] sensu stricto? [Sphenodontinae (Cope, 1896 [1870]) Nopcsa, 1928 sensu Wu, 1994]
                  |--o †Homoeosaurus Meyer, 1850
                  |  |?- †H. pulchellus
                  |  |-- †H. maximiliani
                  |  `-- †H. solnhofeni Cocude-Michel, 1963
                  `--+--o †Kallimodon Cocude-Michel, 1963
                     |  |-- †K. pulchellus [= Homoeosaurus pulchellus??]
                     |  `-- †K. cerinesis
                     `--+--o “Sapheosaurini”
                        |  |-- †Ankylosphenodon pachyostosus Reynoso, 2000
                        |  `--o †Sapheosaurus von Meyer, 1850 [Piocormus]
                        |     |-- †S. thiollierei Meyer, 1850
                        |     `-- †S. laticeps Wagner [Piocormus laticeps]
                        `--+-- †Pamizinsaurus tlayuaensis Reynoso, 1997
                           `--+--o Sphenodontinae (Cope, 1896) sensu Rauhut, Heyng, López-Arbarello & Hecker, 2012
                              |  |-- †Zapatadon ejidoensis Reynoso & Clark, 1998
                              |  |-- †Oenosaurus muehlheimensis Rauhut, Heyng, López-Arbarello & Hecker, 2012
                              |  |?-+-- †Theretairus antiquus (Simpson, 1926)
                              |  |  `-- †Sphenovipera jimmysjoyi Reynoso, 2005; M.Jur. SWNAm.
                              |  `--o Sphenodontini Cope, 1896 [1870]
                              |     |-- †Cynosphenodon huizachalensis Reynoso, 1996
                              |     `--o Sphenodon Gray, 1831 (tuataras; tuatarat)
                              |        |?- cf.S. sp. E.Mioc. NZ. (Jones et al., 2009)
                              |        |?- †S. diversum Colenso, 1885
                              |        |-- S. guentheri Buller, 1877 (Brothers Island tuatara; pikkutuatara)
                              |        `--o S. punctatus (Gray, 1842) (Northern tuatara; isotuatara, tuatara)
                              |           |-- †S. p. reischeki
                              |           |-- S. p. ssp. (Cook Strait tuatara; cookinsalmentuatara)
                              |           `-- S. p. punctatus (northern tuatara)
                              `--o Opisthodontia Apesteguia & Novas, 2003
                                 |-- †Opisthias rarus Gilmore, 1910 [Theretarius antiquus Simpson, 1926 (juv.)]; U.Jur. SWNAm.
                                 `--o †Eilenodontini Rasmussen & Callison, 1981 [Eilenodontinae Rasmussen & Callison, 1981]
                                    |-- †Toxolophosaurus cloudi Olson, 1960 [non Throckmorton, Hopson & Parks, 1981]
                                    `--+-- †Priosphenodon avelasi Apesteguia & Novas, 2003
                                       `-- †Eilenodon robustus Rasmussen & Callison, 1981

Sphenodontia incertae sedis:

Sphenodontian yet unassignated to phylogeny.

Sphenodontidae gen. et sp. indet. [Evans & Sigogneau-Russell, 1997] [Early Cretaceous, Western North Africa]
    †Derasmosaurus Barbera & Macuglia, 1988 [Chometokadmon Costa, 1864 (in partim)] L.Cret. SEu.
    †Elachistosuchus hueni Janensch, 1949; U.Trias. CEu. [Elachistosuchoidea v. Huene, 1956; Elachistosuchidae Romer, 1966]Godavarisaurus leteefi Evans, Prasad & Manhas, 2001
    †Kawasphenodon expectatus Apesteguia, 2005; U.Cret. SAm.
    †Lamarquesaurus cabazai Apesteguia & Rougier, 2007; U.Cret. SAm.
    †Leptosaurus Fitzinger, 1837
        †Leptosaurus neptunius Fitzinger, 1837
        †Leptosaurus pulchellus Zittel 1887
    †Pelecymela Fraser, 1986
    †Paleollanosaurus fraseri Heckert, 2004
    †Sigmala sigmala Fraser, 1986 [Sigmala sigmala Fraser & Walkden, 1983 (nomen nudum)]; U.Trias. WEu.
    †Tingitana anoualae Evans & Sigogneau-Russell, 1997; L. Cret. WNAf.
    –Whitakersaurus bermani Heckert, Lucas, Rinehart & Hunt, 2008: L.Trias. SWNAm.

Alternative phylogenies of Sphenodontia

After Rauhut, Heyng, López-Arbarello & Hecker, 2012

<==o Rhynchocephalia
   |-- †Gephyrosaurus
   `--o Sphenodontia
      |-- †Diphydontosaurus
      `--+-- †Planocephalosaurus
         `--o Sphenodontidae
            |--+-- †Homoeosaurus
            |  `--o “Clevosaurs”
            |     |-- †Brachyrhinodon
            |     |-- †Clevosaurus hudsoni
            |     `-- †Clevosaurus wangi
            `--+--o †Pleurosauridae
               |  |-- †Palaeopleurosaurus
               |  `-- †Pleurosaurus
               `--+--+-- †Kallimodon
                  |  `-- †Sapheosaurus
                  `--+--o Sphenodontinae
                     |  |-- Sphenodon
                     |  `--+-- †Oenosaurus
                     |     `--+-- †Cynosphenodon
                     |        `-- †Zapatodon
                     `--o †Opisthodontia
                        |-- †Opisthias
                        `--o †Eilenodontinae
                           |-- †Toxolophosaurus
                           `--+-- †Eilenodon
                              `-- †Priosphenodon

Reference(s):

  • Rauhut, O. W. M., Heyng, A. M., López-Arbarello, A. & Hecker, A., 2012: A New Rhynchocephalian from the Late Jurassic of Germany with a Dentition That Is Unique amongst Tetrapods.
    –Plos One: Vol. 7, #10, pp. e46839 [doi: 10.1371/journal.pone.0046839]

Reference(s):