Riojasauridae

Riojasauridae is an extinct family of sauropodomorph dinosaurs from the Late Triassic Period (late Carnian to Norian Ages). It contains the genera Riojasaurus and Eucnemesaurus. The Riojasauridae is considered a stem taxon, and is defined as "the most inclusive clade containing Riojasaurus incertus but not Plateosaurus engelhardti, Massospondylus carinatus, or Anchisaurus polyzelus". Geologic formations containing riojasaurid fossils include the Lower Elliot Formation of Orange Free State, South Africa (where fossils of Eucnemesaurus have been found), and the Los Colorados Formation, in La Rioja Province, Argentina (where fossils of Riojasaurus have been recovered).

==Evolutionary relationships== The Riojasauridae are considered to be sauropodomorphs, but not sauropods themselves. This means that they were generally much smaller than the Sauropods of the Jurassic and Cretaceous Periods, and members of this family may not have been obligate quadrupeds, the way more derived Sauropods were. The relationships of this family within other sauropodomorphs has been considered by studies in 2007 and 2020 with slightly different results.