Plesiosauridae, nwere olu dị ogologo na nke dịtụ ogologo; Elasmosauridae, nwere ogologo, olu na-agbanwe agbanwe na obere; na Cimoliasauridae, otu obere ìgwè nke obere Cretaceous forms. Dịka nhazi ọdịnala, plesiuroosaurids niile nwere obere isi na olu ogologo, mana na nhazi ndị na-adịbeghị anya, otu mkpụmkpụ na nnukwu isi Cretaceous, otu okwu Polycosauridae, gụnyere n'okpuru iri abụọ Plesiosauridae, na-eto eto n'okpuru atọ metosaurids, na-eto eto n'okpuru atọ metosaurids.
ndị pistosaurs