Elasmosauridae

Elasmosaurids Temporal range: Late Triassic - Late Cretaceous, 210–66 Ma PreЄ Є 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
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	†Sauropterygia
Order:	†Plesiosauria
Clade:	†Xenopsaria
Family:	†Elasmosauridae Cope, 1869
Genera
See text
Synonyms
Cimoliasauridae Persson, 1960

Elasmosauridae was a family of plesiosaurs. They had the longest necks of the plesiosaurs and survived from the Late Triassic to the end of the Cretaceous. Their diet mainly consisted of crustaceans and molluscs.

Size

Restoration of Thalassomedon haningtoni.

The earliest elasmosaurids were small, about 3 m (9.8 ft). At the end of the Cretaceous, elasmosaurids grew as large as 14 m (46 ft), such as Elasmosaurus. Their necks were the longest of all the plesiosaurs, with anywhere between 32 to 76 (Albertonectes) cervical vertebrae They weighed up to several tons.

Taxonomy

The family Elasmosauridae was erected by Cope in 1869, and anchored on the genus Elasmosaurus.

Family Elasmosauridae Albertonectes Aphrosaurus Callawayasaurus Cardiocorax Elasmosaurus Eromangasaurus Fresnosaurus Futabasaurus Hydralmosaurus Hydrotherosaurus Libonectes Mauisaurus Styxosaurus Terminonatator Thalassomedon Tuarangisaurus Vegasaurus Wapuskanectes Zarafasaura Subfamily Aristonectinae Aristonectes Kaiwhekea

Dubious Elasmosaurids Cimoliasaurus Goniosaurus Ogmodirus Orophosaurus Woolungasaurus

Phylogeny

Elasmosauridae (Cope, 1869) is a stem-based taxon defined in 2010 (and in earlier studies in a similar manner) as "all taxa more closely related to Elasmosaurus platyurus than to Cryptoclidus eurymerus, Leptocleidus superstes, Plesiosaurus dolichodeirus or Polycotylus latipinnis". The cladogram below follows, showing only Elasmosauridae interrelationships, the results of O’Gorman et al. (2015) who performed the most inclusive phylogenetic analysis focusing on Elasmosauridae interrelationships to date.

Elasmosauridae

Eromangasaurus australis Tuarangisaurus keyesi Elasmosaurus platyurus Libonectes morgani Callawayasaurus colombiensis "Libonectes" atlasense Hydralmosaurus serpentinus Hydrotherosaurus alexandrae Aphrosaurus furlongi Terminonatator ponteixensis Thalassomedon haningtoni Styxosaurus snowii Albertonectes vanderveldei Futabasaurus suzukii Mauisaurus haasti Wapuskanectes betsynichollsae Morenosaurus stocki Vegasaurus molyi  Aristonectinae  Aristonectes parvidens Kaiwhekea katiki

External links

• "Lepidosauromorpha: Elasmosauridae." Palaeos.com