 Until recently many dryosaurids have been regarded as dubious ("Callovosaurus" and "Kangnasaurus") or as species of the type member, "Dryosaurus" ("Dysalotosaurus", "Elrhazosaurus" and "Valdosaurus").However, more recent studies redescribe these genera as valid.The cladogram below follows Paul M. Barrett, Richard J. Butler, Richard J. Twitchett and Stephen Hutt (2011).