Elasmosauridae

Elasmosauridae Temporal range: Hauterivian-Maastrichtian, 130–66 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Reconstructed skeleton of Elasmosaurus platyurus in the Rocky Mountain Dinosaur Resource Center in Woodland Park, Colorado.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	†Sauropterygia
Order:	†Plesiosauria
Clade:	†Xenopsaria
Family:	†Elasmosauridae Cope, 1869
Genera
†Alexeyisaurus? †Callawayasaurus †Cimoliasaurus[1] †Eromangasaurus †Fresnosaurus †Jucha †Leurospondylus? †Mauisaurus †Ogmodirus? †Plesioelasmosaurus[2] †Scanisaurus †Wapuskanectes[3] †Woolungasaurus[4] †Zarafasaura[5] †Euelasmosaurida[6] †Cardiocorax[7] †Libonectes †Thalassomedon †Elasmosaurinae †Albertonectes †Elasmosaurus †Fluvionectes †Hydrotherosaurus †Nakonanectes[8] †Styxosaurus †Terminonatator †Weddellonectia[9][10] †Aphrosaurus †Chubutinectes[11] †Futabasaurus †Kawanectes †Marambionectes[12] †Morenosaurus †Tuarangisaurus †Vegasaurus †Aristonectinae
Synonyms
Cimoliasauridae Persson, 1960

Elasmosauridae is an extinct family of plesiosaurs, often called elasmosaurs. They had the longest necks of the plesiosaurs and existed from the Hauterivian to the Maastrichtian stages of the Cretaceous, and represented one of the two groups of plesiosaurs present at the end of the Cretaceous alongside Polycotylidae.