store air to breath. However, it has now been proven that the crest did not have any holes in the end, and the water pressure at even would be too great for the lungs to be able to inflate. Growth Corythosaurus casuarius is one of a few lambeosaurines, along with Lambeosaurus lambei, Hypacrosaurus stebingeri and H. altispinus, to have had surviving fossilized juveniles assigned to it. Juveniles are harder to assign to species, because at a young age they lack the distinctive larger crests of adults. As they age, lambeosaurine crests tend to grow and become more prominent come maturity. In the Dinosaur Park Formation, over fifty articulated specimens have been found, coming from many different genera. Among them, juveniles are hard to identify at the species level. Earlier, four genera and thirteen species were recognized from the formation's area, when paleontologists used differences in size and crest shape to differentiate taxa. The smallest specimens were identified as Tetragonosaurus, now seen as a synonym of Procheneosaurus, and the largest skeletons were called either Corythosaurus or Lambeosaurus; an adult was identified as Parasaurolophus. Small lambeosaurines from the Horseshoe Canyon Formation were referred to Cheneosaurus. Corythosaurus started developing its crest when half the size of adults, but Parasaurolophus juveniles grew crests when only 25% as long as adults. Juvenile Corythosaurus, along with adults, had a premaxilla-nasal fontanelle. Young and adult Corythosaurus are similar to Lambeosaurus and Hypacrosaurus but dissimilar to Parasaurolophus in that the sutures of the skull are sinuous, and not smooth and straight. This feature helps differentiate parasaurolophins from lambeosaurins. Generally, the crests of juveniles of lambeosaurines like Corythosaurus, Lambeosaurus, Hypacrosaurus stebingeri, parasaurolophines like Parasaurolophus, and primitive lambeosaurines like Kazaklambia are quite alike, although other features can be used to distinguish them. 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. erectofrons was assigned to Corythosaurus based largely on biometric information. The only non-typic specimen of Tetragonosaurus, assigned to T. erectofrons, was found later to be referable to Hypacrosaurus, although the holotype of the species was still found to be assignable to Corythosaurus. Diet Corythosaurus was an ornithopod, and therefore a herbivore. Benson et al. (2012) realized that the beak of Corythosaurus was shallow and delicate, and concluded that it must have been used to feed upon soft vegetation. Based on the climate of