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
- Archaeonectrus (according to Smith and Dyke, [2008])
- Borealonectes
- Eurycleidus
- Leptocleidus (according to O'Keefe, 2001)
- Macroplata
- Maresaurus
- Meyerasaurus
- Rhomaleosaurus
- Simolestes (according to O'Keefe, 2001)
- Sthenarosaurus
- Umoonasaurus
- 'Thaumatosaurus' = nominum dubium
