Taxonomic Implications of Relative growth in Lambeosaurine Hadrosaurs

Taxonomic implications of relative growth in lambeosaurine hadrosaurs. Syst. Zool. 24:37–54.—The Oldman Formation (Campanian) of Alberta includes in its dinosaurian fauna 3 genera and 12 species of closely related lambeosaurine hadrosaurs. A biometric study of 36 skulls that ranged in size by a factor of three was undertaken; the data were fitted to the allometric equation. Bivariate plots reveal the validity of two genera, Corythosaurus and Lambeosaurus, with one species of the former, C casuarius, and two of the latter, L. lambei and L. magnicristatus (quiterare), being accepted. Sexual dimorphism is recognized in each. Procheneosaurus includes juvenile individuals of each genus. Although 48 cranial characters were measured, only 5 or 6, confined to the crest, had any discriminatory value. The analogy between cassowaries and hadrosaurs in growth of the crest is observed. The sex ratio and maximum size of each sex is about equal for both common species.