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.
- Archaeonectrus (according to Smith and Dyke, )
- Leptocleidus (according to O’Keefe, 2001)
- Simolestes (according to O’Keefe, 2001)
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