Corythosaurus was a large, herbivorous dinosaur belonging to the Hadrosauridae family, commonly referred to as the duck-billed dinosaurs. It is instantly recognizable by the distinctive, tall, helmet-like crest atop its skull, which led to its name meaning “Corinthian helmet lizard.” As a member of the Lambeosaurinae subfamily, its biology is well-understood due to the abundance of well-preserved fossil material found, including nearly complete skeletons and skin impressions. Tracing these fossils back to their geographical locations helps reconstruct the ancient world this massive herbivore inhabited.
Geographic Location of Discovery
The primary fossil evidence for Corythosaurus is concentrated in a region of North America, crossing the modern border between Canada and the United States. The most significant specimens, including the nearly complete holotype skeleton, were unearthed in the rich fossil beds of Alberta, Canada. This area, particularly Dinosaur Provincial Park, has yielded numerous skulls and associated skeletal remains.
The remains are predominantly found in the Dinosaur Park Formation, a geological layer known for preserving ancient river and coastal deposits. Fossils have also been recovered from the underlying Oldman Formation in Alberta, which represents slightly older deposits. Corresponding material has been discovered further south in Montana, USA, indicating the dinosaur’s range extended across this ancient landscape during the Late Cretaceous period.
The Late Cretaceous Timeline
Corythosaurus existed during the Late Cretaceous period, specifically the Campanian Stage, approximately 77 to 75.7 million years ago. At this time, the North American continent was split in two by the Western Interior Seaway, a vast, shallow sea extending from the Gulf of Mexico to the Arctic Ocean.
This seaway created two island continents: Appalachia to the east and Laramidia to the west. Corythosaurus lived exclusively on Laramidia, a narrow landmass stretching from modern-day Alaska down to Mexico. This geographical isolation contributed to the evolution of unique dinosaur faunas, including diverse duck-billed dinosaurs.
Environment of Laramidia
The home of Corythosaurus was a lush, low-lying environment shaped by its proximity to the Western Interior Seaway. The climate of Laramidia during the Campanian Stage was warmer and more humid than the modern environment of Alberta and Montana. The conditions were sub-tropical, supporting extensive vegetation across the landscape.
The habitat consisted largely of coastal floodplains, river deltas, and dense swamps. This wet environment provided ample food for the large herbivore. The diet of Corythosaurus included a variety of plants, such as conifers, ferns, and flowering plants (angiosperms).
Evidence from preserved gut contents suggests they consumed tough, fibrous materials, including twigs, seeds, and conifer needles. The soft, muddy sediments of this environment were also ideal for preserving the skeletons and skin of these animals, aiding in the reconstruction of their ancient world.