ELASMOSAURIDAE

Sauropterygia > Eosauropterygia > Eusauropterygia > Plesiosauria > Plesiosauroidea> Elasmosauridae

Discussion

Characteristically very long necked plesiosaurs, elasmosaurids form the major component of Late Cretaceous plesiosaur assemblages. However, their total range spans throughout the Jurassic and Cretaceous (Cruickshank et al. 2002).

Synapomorphies (shared derived characters) of the clade Elasmosauridae include (Bardet et al. 1999)

• Ventral cheek margin weakly excavated
• Palate lacks anterior pterygoid vacuity
• Platycoelus (flat articulation surfaces) to the vertebrae
• >40 cervical vertebrae, with cervical centra longer than high
• Mid-anterior cervical vertebrae with lateral keel

Members

'Alzadasaurus'

Callawayasaurus

Elasmosaurus

Eretmosaurus (According to Bardet ????)

Hydralmosaurus

Hydrotherosaurus

Libonectes

Microcleidus

Occitanosaurus

Styxosaurus

Thalassomedon

Tuarangisaurus

'Woolungasaurus'