After Laurin, 1996a,b and Berman, Henrici, Sumida & Martens, 2000

<==o †Seymouriamorpha Watson, 1917
   |?- †“Rhipaeosaurus” talonophorus [Leptoropha novojilovi]
   |?- †Microphon exiguus Ivakhnenko, 1983 [Raphaniscus tverdochlebovae] [has long been treated as a procolophonid reptile (Säilä, 2009)]
   |-- †Urumqia liudaowanensis Zhang, Li & Wang, 1984
   |-- †Utegenia shpinari Kuznetsov & Ivakhnenko, 1981
   |?- †Waggoneria knoxensis Olson, 1951 [Waggoneriidae Olson, 1951]
   |--o †Kotlassiidae Romer, 1933 [incl.? Bystrowianidae Vjuschkov, 1957; Karpinskiosauridae Sushkin, 1925]
   |  |?-o †Axitectum Shishkin & Novikov, 1992 [Bystrowianidae]
   |  |  |-- †A. vjushkovi Shishkin & Novikov, 1992
   |  |  `-- †A. georgi Shishkin & Novikov, 1992
   |  |?- †Buzulukia Vjuschkov, 1957
   |  |-- †Bystrowiana permira Vjuschkov, 1957 [Bystrowianidae]
   |  |?- †Dromotectum spinosum Novikov & Shishkin, 1996 [Bystrowianidae]
   |  |?- †Enosuchus breviceps Konzhukova, 1955
   |  |--o †Karpinskiosaurus Sushkin, 1925 [Karpinskiosauridae Sushkin, 1925]
   |  |  |-- †K. secundus (Amalitzky, 1921) [Kotlassia secunda Amalitzky, 1921]
   |  |  `-- †K. ultimus (Tchudinov and V'yushkov, 1956) [Nycteroleter ultimus Tchudinov & V'yushkov, 1956)
   |  |-- †Kotlassia prima Amalitzky, 1898
   |  `?- †Synesuchus muravjevi Novikov & Shishkin, 2000 [Bystrowianidae]
   `--+--o †Discosauriscidae Romer, 1947 sensu stricto
      |  |-- †Makowskia laticephala Klembara, 2005
      |  `--o †Discosauriscus Kuhn, 1933 [taxonomic history]
      |    |-- †D. austriacus (Makowsky, 1876) [taxonomic history]
      |    `-- †D. pulcherrimus (Fritsch, 1879) [taxonomic history]
      `--+-- †Ariekanerpeton sigalovi Ivakhnenko, 1981
         `--o †Seymouriidae Williston, 1911
            |-- †Gnorhinosuchus
            |?- †Nyctiboetus liteus Chudinov 1955 [a nyctiphruretid according to Paleobiology Database]
            |-- †Rhinosauriscus Kuhn, 1963
            `==o †Seymouria Broili, 1904; L.Perm. NAm. Eu.
               |?- †Desmospondylus anomalus Williston, 1910; L.Perm. NAm. Eu.
               |?- †S. agilis
               |?- †S. grandis
               `--+-- †S. sanjuanensis Vaughn, 1966
                  `-- †S. baylorensis Broili, 1904 [Conodectes favosus Cope, 1896; Seymouria baylorensis Broili, 1904; Conodectes favosus Case, 1911; Seymouria baylorensis Laurin, 1996]

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