Base of the evolutionary tree for Sauropterygiformes

• Sauropterygiformes (87 species)
  • unnamed group 1144 → (86 species)
    • Sauropterygia → (84 species)
      • Eosauropterygia → (83 species)
        • Pistosauria → (71 species)
        • unnamed group 1148 → (12 species)
      • Placodontiformes
    • unnamed group 1145 → (2 species)
      • Eusaurosphargis
      • Palatodonta
  • Helveticosaurus