The ‘fabrosaurid’ ornithischian dinosaurs of the Upper Elliot Formation (Lower Jurassic) of South Africa and Lesotho

The Upper Elliot Formation of South Africa and Lesotho contains the world's most diverse fauna of early Jurassic ornithischian dinosaurs. Nevertheless, despite four decades of work on this fauna there remains significant taxonomic confusion and many important specimens remain undescribed. A review of the non-heterodontosaurid ('fabrosaurid') ornithischians of the Upper Elliot Formation is presented, following re-examination of all known ornithischian material from the Elliot Formation. 'Fabrosaurus australis' is based upon a single undiagnostic dentary, and is here considered a nomen dubium. Lesothosaurus diagnosticus is considered to be valid and is rediagnosed based upon a unique combination of plesiomorphic and derived characteristics. Stormbergia dangershoeki gen. et. sp. nov. is described from three partial skeletons including numerous postcranial material. Stormbergia dangershoeki is significantly larger than previously described Elliot Formation ornithischians, and can be recognized on the basis of a unique combination of characters, the most important of which is the possession of a distinctive tab-shaped obturator process on the ischium. A preliminary systematic analysis is presented, the results of which differ significantly from other recent ornithischian phylogenies.