Last time, we saw why Haplocanthosaurus couldn’t be a juvenile of Apatosaurus or Diplodocus , based on osteology alone.  But there’s more: Ontogenetic status of Haplocanthosaurus Here is where is gets really surreal.  Woodruff and Fowler (2012) blithely assume that Haplocanthosaurus is a juvenile of something, but the type specimen of the type species — H .