The dinosaur Corythosaurus (Core-ith-oh-soar-us) was so named because the bony crest upon its head suggests a Corinthian war helmet. It lived in Alberta Canada during the Late Cretaceous Period about 75 million years ago. The dinosaur was about 30 feet in length.
The peculiar helmet-like crest was hollow and was formed primarily by the nasal bones. Air followed a somewhat tortuous circuit from the nostrils. The nasal passages began as separate channels (left and right) leading into the crest and then merged to form a single chamber before moving on into the throat region and respiratory system. The function of the crest is unclear. When it was thought that hadrosaurs (duck-billed dinosaurs) were largely aquatic, it was assumed that the crest might serve to store air while the animal dived and fed under water. More recently, it has been suggested that the crest enhanced the sense of smell or was used to make low-frequency sounds for communication. It is also possible that the crest served as a visual display to help identify species and sex. Without a living Corythosaurus to study, however, it is impossible to tell for certain.
Corythosaurus is represented by some outstanding fossil skeletons. Skin impressions on some specimens show clearly what the skin texture was like. Evidently, the skin was elaborately patterned and it sported numerous armor plates ranging up to an inch and a half in diameter.
A number of species of Corythosaurus have been recognized over the years, distinguished mostly by size and the specific shape of the crest. Today, only one species is generally recognized - the differences in size and shape being attributed to age, sex, and individual variation.
As in all duck-billed dinosaurs, the mouth of Corythosaurus was filled with batteries of teeth designed to pulverize rough vegetation. Corythosaurus specimens have been preserved with stomach contents showing that they ate conifer needles, twigs, seeds, and fruits.
A splendid Corythosaurus skeleton at the American Museum of Natural History