All rhomaleosaurids have a relatively large head with a reasonably long neck composed of about 28 vertebrae. The group has a stratigraphical range from the Lower Jurassic to the Middle Jurassic.

Rhomaleosaurid phylogeny

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

Rhomaleosaurid genera

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

  • ‘Thaumatosaurus’ = nominum dubium