After Rieppel & †Zanon, 1997, Rieppel, 2000, and Naish, 2000-2004

Family -level taxonomy of all sauropterygians.
<==o †Placodontia Cope, 1871 sensu Rieppel, 2000
   |?- †Chelyoposuchus crassisquamatus [jr. synon. of Helodus?]
   |?- †Helveticosaurus zollingeri [?Helveticosauridae] [an aquatic non-sauropterygian archosauromorph (Rieppel 1989)??]
   `--o †Placodontoidea Cope, 1871 (sensu Peyer & Kuhn-Schnyder 1955, and Rieppel & †Zanon, 1997) [paraphyletic sensu Rieppel, 2000]
      |?- †Saurosphargis voltzi v. Huene, 1936 [type destroyed in WWII]
      |-- †Paraplacodus broilii Peyer, 1931a [Paraplacodontidae Peyer & Kuhn-Schnyder, 1955]
      `--+--o †Placodus Agazzis, 1833 [Anomosaurus, Crurosaurus]  L.-M. Trias. Eu. M. Trias. SWAs. [Placodontidae Cope, 1871]
         |  |-- †P. gigas Agazzis, 1833 [P. aethiopi; P. aethiops; P. andriani; P. angustus; P. antiquior; P. bathygnathus; P. bombidens; P. pachygnathus; P. quinimolaris; P. rugosus; P. strunzi]
         |  `-- †P. nostratus
         `--o †Cyamodontoidea Nopsca 1923 (sensu Peyer & Kuhn-Schnyder 1955
            |?- †Psephosaurus mosis Brotzen, 1957
            |?- †“Psephosaurus” picardi Bronzen, 1957
            |?- †“Psephosaurus” sinaiticus Haas, 1959
            |?- †“Psephosaurus” rhombifer Haas, 1969
            |?- †“Psephosaurus” ramonensis (nomen nudum)
            |?- †“Psephosaurus” suevicus
            |--+-- †Henodus chelyops v. Huene, 1936 [Henodontidae]
            |  `--o †Cyamodus Meyer 1863 [Cyamodontidae]
            |     |-- †C. rostratus (Münster, 1839)
            |     |-- †C. munsteri (Agassiz, 1833-45) [C. münsteri; C. laticeps?] [jr. synon. of C. rostratus?]
            |     |?- †C. tarnowitzensis Gürich, 1884 [type lost in WWII]
            |     |-- †C. hildegradis Peyer, 1931a
            |     `-- †C. kuhnschnyderi Nosotti & Pinna 1993 [C. kuhn-schnyderi (Nosotti & Pinna 1993a]
            `--+?- Macroplacus raeticus Schubert-Klempnauer, 1975 [possibly synon. to Psephoderma alpinum]
               `--+-- Protenodontosaurus italicus Pinna, 1990
                  `--o †Placochelyidae
                     |-- †Placochelys placodonta Jaekel, 1902 [Placochelyanus]
                     `--o †Psephoderma Meyer, 1858
                        |-- †P. alpinum Meyer, 1858 [Placochelyanus stoppanii Kuhn, 1969; Placochelys malanchinii; Placochelys stoppanii; Placodus zitteli; ?Macroplacus raeticus Schubert-Klempnauer, 1975; ?Placochelys alpis sordidae]
                        `-- †P. anglicum Meyer, 1867

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