Indeed one of these associations has been named: Eucnemosaurus fortis Van Hoepen, 1920.
Cladistic analysis of basal sauropodomorph relationships finds that Riojasaurus and Eucnemosaurus are sister taxa within a large clade that also contains Massospondylidae, Yunnanosaurus, Anchisauridae, Melanorosauridae, Antetonitrus and traditional sauropods (Vulcanodontidae and Eusauropoda) to the exclusion of Plateosauridae and more basal sauropodomorphs.
*Massospondylus* as a sauropod. Will I ever get used to this... ;-)
Those old prosauropod names appear to be making a comeback (_Eucnemosaurus_,
_Plateosauravus_, _Gresslyosaurus_, etc).
Though I wonder what the maxilla does belong to...?
Yes...