Eromangasaurus Sauropterygia Koleken Elasmosaurus Libonectes Paraplacodus Nothosaur Pliosauridae Plesiosauria Henodus Atopodentatus Plesiosaurus Henodontidae Placodontia Kronosaurus Dolichorhynchops Placodus Pliosaurus Attenborosaurus Liopleurodon Neusticosaurus Nothosaurus