Rhomaleosauridae


Classification

Sauropterygia–>
Eosauropterygia–>
Eusauropterygia–>
Pistosauroidea–>
Plesiosauria–>
Pliosauroidea–>
Rhomaleosauridae

All rhomaleosaurids share a rather large head with a reasonably long neck composed of about 28 vertebrae. The group ranges from the Lower Jurassic to the Middle Jurassic. Characters:

  • Ventral cheek margin weakly excavated
  • Pterygoids on palate closed anteriorly (lacks anterior pterygoid vacuity)
  • Platycoelus (flat articulation surfaces) to the vertebrae
  • Greater than 40 cervical vertebrae
  • cervical centrum length greater than height
  • Anterior cervical vertebrae with lateral keel

Rhomaleosaurid phylogeny

Cladogram of rhomaleosaurid pliosaurs (from Smith and Dyke, 2008)

Rhomaleosaurid genera

Several elasmosaurid genera are considered nomina dubia or are regarded as junior synonyms of other genera. The following names are therefore invalid :

  • ‘Thaumatosaurus’ = nominum dubium