 Work by Dodson ( 1975 ) recognized that there were many less taxa present in Alberta . Tetragonosaurus was found to be juveniles of Corythosaurus or Lambeosaurus . T. <unk> was assigned to Corythosaurus based largely on <unk> information . The only non @-@ <unk> specimen of Tetragonosaurus , assigned to T. <unk> , was found later to be <unk> to Hypacrosaurus , although the holotype of the species was still found to be <unk> to Corythosaurus . 
