Genus
Plesiosaurus de la Beche and Conybeare, 1821
Classification
| Organism group | Biota |
| Kingdom | Animalia |
| Phylum | Chordata |
| Subphylum | Vertebrata |
| Infraphylum | Gnathostomata |
| Superclass | Tetrapoda |
| Class | Reptilia |
| Subclass | Eureptilia |
| unranked | Diapsida |
| Order | Sauropterygia |
| Family | Cyamodontidae |
| Nothosauridae | |
| Placodontidae | |
| Genus | Plesiosaurus |
See also