Cranial crest ontogeny on lambeosaurine dinosaurs
DAVID EVANS
Dept. of Natural History, Royal Ontario Museum, Toronto, ON
Lambeosaurinae is a monophyletic clade of large herbivorous ornithischian dinosaurs characterized by hypertrophied nasal passages housed within distinctive cranial crests. Excellent cranial ontogenetic series are known for four closely related taxa from Alberta, Canada: Corythosaurus casuarius, Lambeosaurus lambei, Hypacrosaurus altispinus and H. stebingeri. Juveniles of all taxa have similar incipiently developed crests, and diverge in crest morphology during the active phase of crest growth. Differences in crest growth in these taxa are investigated using qualitative comparisons and morphometric analyses. The first species-level hypothesis of lambeosaurine interrelationships allows initial exploration of crest heterochrony within the clade.