After Erickson, 1987, Cvancara & Hoganson, 1993, and Gao & Fox, 1998, 2005

<==o †Choristodera Cope, 1884 (non Cope, 1876) (champsosaurs; champsosaurit)
   |?- †Choristodera genera et species indet. [Averianov, Martin, Evans & Bakirov, 2005] [M.Jur. CA.]
   |?- †Irenosaurus egloni (Efimov, 1983) [Tchoiria egloni Efimov, 1983, Irenosaurus Efimov, 1988]
   |?-o †Khurendukhosaurus Sigogneau-Russell & Efimov, 1984
   |  |-- †K. bajkalensis Efimov, 1996
   |  `-- †K. orlovi Sigogneau-Russell & Efimov, 1984
   |?-o †Lazarussuchus Hecht, 1992; U.Olig.-L.Mioc. Eu. [Lazarussaurus (lapsus calami)] [non-Choristodere sensu Gao & Fox, 2005]
   |  |-- †L. inexpectatus Hecht, 1992
   |  `-- †L. dvoraci Evans & Klembara, 2005
   `--+--o †Cteniogelys Gilmore, 1928; M.-U.Jur. NA. [Cteniogenidae Seiffert, 1973]
      |  |-- †C. sp., cf. C. antiquus
      |  `-- †C. antiquus Gilmore, 1928
      `--+-- †Pachystropheus rhaeticus Huene, 1935; U.Trias.
         |--o †Monjurosuchidae Endo, 1940
         |  |-- †Philydrosaurus proseilus Gao & Fox, 2005; L.Cret. EAs.
         |  `-- †Monjurosuchus splendens Endo, 1940; L.Cret. EAs.
         |--o †Hyphalosauridae Gao & Fox, 2005
         |  |-- †Shokawa Evans & Manabe, 1999
         |  `--o †Hyphalosaurus Gao, Tang & Wang, 1999 [Sinohydrosaurus Li, Zhang & Li, 1999] L.Cret. EAs.
         |     |-- †H. lingyuanensis Gao, Tang & Wang, 1999 [Sinohydrosaurus lingyuanensis Li, Zhang & Li, 1999]
         |     `-- †H. baitaigouensis Q. Ji, S. Ji, Cheng, You, Lü & Yuan, 2004
         `--o †Neochoristodera Evans & Hecht, 1993 [Champsosauriformes Hay, 1929 (nomen oblitum)]
            |--o †Simoedosauridae Lemoine, 1884
            |  |-- †Tchoiria namsarai Efimov, 1975
            |  `--+--o †Ikechosaurus Sigogneau-Russell, 1981
            |     |  |-- †I. sunailinae Sigogneau-Russell, 1981
            |     |  |-- †I. magnus (Efimov, 1979) [Tchoiria magnus Efimov, 1979]
            |     |  `-- †I. pijiagouensis Liu, 2004
            |     `--o †Simoedosaurus Gervais, 1877
            |        |-- †S. lemoinei Gervais, 1877
            |        |-- †S. sp. [UALVP 33927]
            |        `-- †S. dakodensis Erickson, 1987
            `--o †Champsosauridae Cope, 1884 (champsosaurit)
               |-- †Eotomistoma
               `--o †Champsosaurus Cope, 1876
                  |-- †C. profundus Cope, 1876
                  |-- †C. annectens Cope, 1876
                  |?- †C. breficollis
                  |?- †C. dolloi
                  |-- †C. lindoei Gao & Fox, 1998
                  |-- †C. natator Parks, 1933
                  |-- †C. albertensis Parks, 1927
                  |-- †C. gigas Erickson, 1972
                  |-- †C. laramiensis [incl. C. australis Cope, 1884; C. puercensis Cope, 1884; C. saponensis Cope, 1884]
                  |-- †C. ambulator
                  |-- †C. tenius
                  |-- †C. dakotensis
                  `-- †C. sp. [TMM 45818] [Pal. SWNAn.] [Lehman " Barnes, 2010]

Reference(s):