The Corythosaurus was a fairly large herbivorous dinosaur. It was an ornithischian and a hadrosaurid. It existed on the earth about 80 to 74 million years ago. This phase lies in the Campanian age of the Cretaceous period of the Mesozoic Era. The Campanian age lies right before Maastrichtian age, at the end of all dinosaurs were wiped out for good.
The conspicuous feature of this reptile was the bony crest on its forehead and snout. This projection was hollow in nature which has lead scientists to believe that it could have contained an organ for vocalization. It seemed too flimsy to be used as an offensive or defensive weapon.
The length of this dinosaur was about 30 to 31 feet. Its weight was estimated to be around 3 to 3.8 tons. This would make it one of the largest known hadrosaurian dinosaurs. But its size was very modest as compared to the gigantic Cretaceous sauropods, which were among the largest animals to ever walk the earth. The fossils of the creature were discovered in Canada.
The term Corythosaurus is coined from two separate words. The suffix is derives from the Greek words 'kranos' which means 'helmet', and 'korinthos' which is the term for the city of Corinth. The warriors of Corinth wore head gears that resembled the crest of the Corythosaurus. The suffix 'saurus' is derived from a Greek word again, 'sauros', which means 'lizard'. Thus, the name is supposed to denote 'the lizard with the Corinthian helmet'.
The second part of the binomial name C. casuarius is directly borrowed from the generic name of the Cassowary birds, which the Corythosaurus resembled.
The nomenclature of the remains of this dinosaur was done by paleontologist Barnum Brown in 1914.
The Corythosaurus is classified under clade Ornithopod, family Hadrosauridae and tribe Lambeosauirni. Recent research has shown that the dinosaur was more closely related to the Lambeosaurus than the Parasaurolophus.
Many subspecies of the dinosaur were described over the years on the basis of the size and structure of the skull. But recent studies have found that the differences in morphology of the crest were accounted for by the varying ages of the specimens.
Currently, one more species of the Corythosaurus is recognized, apart from the type species C. casuarius, the C. intermedius. The C. intermedius was initially classified by William Parks as the Stephanosaurus intermedius. It was later moved to the genus Corythosaurus, and a study in 2009 found that it was disparate from the C. casuarius. Furthermore, its fossils were a little younger than those of the type species.
Discovery of fossils
- The holotype of the Corythosaurus was discovered along the Red Deer River in Alberta, Canada in 1912. It had probably floated ashore from the river. This specimen consisted of an almost complete skeleton. Only a few appendicular bones had withered away. This fossil was especially diagnostically relevant as it contained pieces of the dinosaur, which showed the presence of thick scales. This skeleton was discovered by Charles Sternberg and was described by Barnum Brown in the year 1914.
- In 1914, another skeleton was discovered by Brown and Kaisen, which Brown attributed to the Corythosaurus.
- Since then, many fossils have been excavated from the Dinosaur Park Formation of Alberta, which have been grouped under the genus Corythosaurus.
- Two of the best preserved Corythosaurus fossils were destroyed in the First World War, when they were being transported to the United Kingdom in 1916 by sea. A German war ship sunk the vessel that was carrying these bones.
The skull of the Corythosaurus was its most unique feature. It was small in size as compared to the body of the dinosaur and consisted of a very large and prominent crest. This crest was composed of the nasal, pre-maxillary, prefrontal and frontal bones. Majority of it was constituted by the paired nasals. The upper and lower jaw of the dinosaur was shaped like a beak. This is described as a ‘duck billed’ jaw and hence the name ‘hadrosaurid’ is given to dinosaurs like the Corythosaurus. The shape and structure of the facial bones is highly modified on the skull of this dinosaur, which made paleontologist Brown confuse one bone for the other on many occasions.
Most of the crest of the Corythosaurus was made up of the nasal bone. It was small in juvenile specimens and gradually attained a size comparable to the width of the skull in adult dinosaurs. It was hollow from inside. Many researchers believe that it could have possessed an organ of vocalization or for enhancing the sense of smell. The former possibility is more likely. Yet some scientists posit that as the crest grew larger and larger till the dinosaur attained adulthood, it could have been a secondary sexual characteristic.
- The Corythosaurus had a length of about 9 to 9.5 meters and a mass of almost 4000 kilos, making one of the largest hadrosaurids.
- The crest of this dinosaur made it similar in appearance to the modern day cassowaries.
- The skin of the Corythosaurus was covered with scales of a variety of sizes. These were concentrated on its flank and tail. The rest of the body was covered by tuberculate bumps, which were modified scales.
- The hands and feet of the dinosaur appeared webbed in the skeletal remains, but these were later found to be foot pad like structures.
- The forelegs of the Corythosaurus were distinctly shorter than its hind legs.
- The tail of the dinosaur was stout at the base and tapering towards the tip.
Habits and habitat
- The Corythosaurus was an herbivore. Its food preferences are known to scientists as one specimen was found to have its meal preserved in the thoracic cavity; it consisted of conifers, seeds, sticks and fruits.
- This animal was bipedal. This allowed it access to higher vegetation, a luxury not available to the ceratopsids and stegosaurs.
- The fossils of the Corythosaurus have been found in close association with those of the Centrosaurus, in multiple locations. This may mean they shared the same microenvironments.
- The habitat of the Corythosaurus was terrestrial grasslands, and not water as previously believed. It may have moved about in swamps though.
Related and coexisting species
The Olorotitan is the closest relative of the Corythosaurus. It shared it environment with dinosaurs such as the Daspletosaurus, Centrosaurus, Parasaurolophus, Chasmosaurus, etc.
The Corythosaurus was present in large number in present day Alberta. Scientists do not know yet why it never left Alberta to migrate elsewhere, despite its formidable size.