The Plesiosaur Directory - Classification

This invalid and now redundant clade arose due to confusion over the affinities of the placodonts. Nothosauriformes was suggested by Storrs (1993) to include the Eusauropterygia (which excludes pachypleurosaurs) and Placodontia. However, there is still dispute surrounding the inclusion of placodonts within the Sauropterygia (Sues, 1986), and a position more derived than the pachypleurosaurs may not be justified. Discounting the clade Nothosauriformes and retaining placodonts as the sister group to all other Sauropterygia is a widely expressed alternative. In this case the valid clade Eosauropterygia may be invoked to encompass all Sauropterygia minus the Placodontia, indeed, this is the current consensus (Rieppel, 2002).