Open Paleo

Corythosaurus

Brown, 1914 ko-RITH-o-SAWR-us /kəˌrɪθəˈsɔːrəs/

From Greek korys (κόρυς), 'helmet', + Greek sauros, 'lizard'; means 'helmeted lizard', referring to its helmet-like head crest

83.6–72.2 million years ago Campanian, Late Cretaceous
Late Cretaceous stages

Corythosaurus is a genus of hadrosaurid "duck-billed" dinosaur from the Late Cretaceous period, about 77-75.7 million years ago, in what is now western North America. Its name is derived from the Greek word κόρυς, meaning "helmet", named and described in 1914 by Barnum Brown. Corythosaurus is now thought to be a lambeosaurine, thus related to Lambeosaurus, Nipponosaurus, Velafrons, Hypacrosaurus, and Olorotitan. Corythosaurus has an estimated length of 7.7-9 meters (25-30 ft) and has a skull, including the crest, that is 70.8 centimeters (27.9 in; 2.32 ft) tall.

Diagnosis

  1. Skull short with a high anterior helmet-like crest formed by nasals, prefrontals, and frontals
  2. Nasals not separated in front by premaxillaries (unique among known hadrosaur genera at time of description)
  3. Narial opening small; mouth narrow with elongate expanded portion of premaxillary in front of nares
  4. Integument composed of low polygonal non-imbricating tuberculate scales on sides, back, and tail, with rows of conical limpet-like scales on belly
  5. Prefrontal roughly triangular and less extensive than in Stephanosaurus; apparently forms no part of the orbital border

Species (2)

Corythosaurus casuarius Brown, 1914

Type species

Named for the cassowary (Casuarius), a modern bird with a similarly prominent skull crest.

Holotype
AMNH 5240 , American Museum of Natural History
Material
Nearly complete skeleton with integument, articulated and complete except for approximately two feet of the tail end and the fore limbs
Horizon
Belly River Group, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
near Steveville, Red Deer River, Alberta, Canada Brown (1914) gives the horizon as "Belly River Beds, 300 feet below top of formation", before the Oldman and Dinosaur Park formations were divided; no source read places the holotype in either.

Corythosaurus intermedius Parks, 1923

From Latin 'intermedius' ('intermediate'), for the crest form, intermediate between those of Lambeosaurus lambei and Corythosaurus casuarius.

Holotype
ROM 776 , Royal Ontario Museum
Material
Nearly complete skull (specimen "A"): crested premaxillae and nasals, maxillae, jugals, squamosals, quadrates, palatines, pterygoids, braincase elements, and right dentary; no postcranial material.
Horizon
Belly River Group, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
1.5 miles south of the river and 2 miles above Happy Jack ferry, Alberta, Canada Parks (1923) gives the holotype from "the badlands of the Belly River formation", at "an elevation of 175 feet (aneroid) above the river"; no source read places it in the Oldman or the Dinosaur Park.
Diagnosis
  1. Crest ascending more gradually from the snout and extending farther back, rather than rising abruptly.
  2. Postero-inferior angle of the crest drawn out into a short, stout process.

References

  1. Brown, B. (1914). Corythosaurus casuarius, a new crested dinosaur from the Belly River Cretaceous, with provisional classification of the family Trachodontidae. Bulletin of the American Museum of Natural History 33(35): 559-564. brown1914b
  2. Parks, W. A. (1923). Corythosaurus intermedius, a new species of trachodont dinosaur. University of Toronto Studies, Geology Series 15: 1-57.

    Original description of Corythosaurus intermedius on skull ROM 776 from the Dinosaur Park Formation of Alberta.

    parks1923a