Editing Corythosaurus (section)

===Growth===
[[File:Corythosaurus cauarius, juvenile skull and jaws, Dinosaur Provincial Park, Alberta, Canada, Late Cretaceous - Royal Ontario Museum - DSC00025.JPG|thumb|left|ROM 759, a juvenile skull, originally named as a separate species, ''Tetragonosaurus erectofrons'']]
''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 that come 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 even identified as ''[[Parasaurolophus]]''.<ref name="evans2005"/> Small lambeosaurines from the [[Horseshoe Canyon Formation]] were referred to ''[[Cheneosaurus]]''.<ref name="evans2005"/>
[[File:Parasaurolophus-Corythosaurus-Casuarius growth.png|thumb|300px|Skull growth of ''Parasaurolophus'' sp., ''Corythosaurus casuarius'' and ''Casuarius'' sp. The stars represent the age at which crest development starts]]
''Corythosaurus'' started developing its crest when they were half the size of adults, but ''Parasaurolophus'' juveniles grew crests when they were 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, not smooth and straight. This feature helps to differentiate Parasaurolophini from Lambeosaurini. 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.<ref name="farke2013">{{Cite journal | last1 = Farke | first1 = A. A. | last2 = Chok | first2 = D. J. | last3 = Herrero | first3 = A. | last4 = Scolieri | first4 = B. | last5 = Werning | first5 = S. | title = Ontogeny in the tube-crested dinosaur ''Parasaurolophus'' (Hadrosauridae) and heterochrony in hadrosaurids | doi = 10.7717/peerj.182 | journal = PeerJ | volume = 1 | pages = e182 | year = 2013 | pmid =  24167777| pmc = 3807589 | doi-access = free }}</ref>

Work by Dodson (1975) recognized that there were many less taxa present in Alberta.<ref name="PD75"/><ref name="evans2005"/> ''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 later found to be referable to ''Hypacrosaurus'', although the holotype of the species was still found to be assignable to ''Corythosaurus''.<ref name="evans2005"/>