Corythosaurus casuarius koh-RITH-oh-SOR-us

"Helmet lizard"

Corythosaurus silhouette — silhouette · Olof Moleman (CC-BY) via PhyloPic

Length: 9 m (29.5 ft) — About 9 m long, ~3 tonnes — known for its rounded cassowary-like crest.
Period: Late Cretaceous (77–75 Mya)
Place: North America · Alberta, Canada
Food: Herbivore — Tough plants, probably including conifer needles and ferns — chewed by a dental battery.
Clade: Hadrosauridae Dinosauria Ornithischia Cerapoda Ornithopoda Iguanodontia Duck-billed dinosaurs with tooth batteries.

A duck-billed dinosaur whose tall helmet crest may have worked like a living trombone.

Corythosaurus had a tall rounded crest shaped like a Greek warrior’s helmet — actually a cassowary-like dome packed with hollow nasal passages. Like Parasaurolophus, the crest worked as a resonating chamber to produce distinctive calls. Males may have had taller crests than females, but proving that requires comparing many specimens.

More about Corythosaurus

Discovery

Named by Barnum Brown · 1911 · Red Deer River of Alberta, in the Belly River Group

Brown discovered the first specimen, AMNH 5240, in 1911 and secured it in the fall of 1912. The find was notable because impressions of much of the animal's skin survived alongside an almost complete skeleton.

The name comes from the Greek "korythos", meaning "helmet", a nod to its tall crest. The species name is "casuarius", and the crest is said to resemble that of a cassowary and a Corinthian helmet.

Portrait of Barnum Brown — Barnum Brown Brown named and described *Corythosaurus* in 1914 and found the holotype himself; he later published a more detailed description in 1916 and revised the animal's classification over time.

What was the tall crest actually for?

The most likely function of the crest is thought to be vocalization. Sound waves would travel through many chambers in the crest, much as in a trombone, and then get amplified when Corythosaurus exhaled. This remains the leading explanation rather than a settled fact.

When was Corythosaurus most active?

Comparisons between its scleral rings and those of modern reptiles suggest it may have been cathemeral, meaning active in short intervals throughout the day. Hadrosaurid hearing also seems to have been well developed, with a thin stapes and large eardrum implying a sensitive middle ear.

What we know

Tall, flat, helmet-shaped crest packed with hollow nasal tubes.
Many complete skeletons known, some with skin impressions preserved.
Lived alongside Gorgosaurus, Centrosaurus, and Lambeosaurus in the Dinosaur Park Formation.
Closely related to Hypacrosaurus and Lambeosaurus.

What we guess

Whether crest shape differed between males and females.
Pitch and pattern of the calls produced by the crest.
Whether young Corythosaurus had different-shaped crests as they grew.