Prosaurolophus

Prosaurolophus Temporal range: Late Cretaceous, 75.5–74.0 Ma PreЄ Є O S D C P T J K Pg N ↓
P. maximus specimen collected 1921, Royal Ontario Museum
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Dinosauria
Order:	†Ornithischia
Suborder:	†Ornithopoda
Family:	†Hadrosauridae
Subfamily:	†Saurolophinae
Genus:	†Prosaurolophus Brown, 1916
Species:	†P. maximus
Binomial name
Prosaurolophus maximus Brown, 1916
Synonyms
P. blackfeetensis Horner, 1992 Saurolophus maximus (Brown, 1916)

P. blackfeetensis Horner, 1992 Saurolophus maximus (Brown, 1916)

Prosaurolophus (/ˌproʊsɔːˈrɒləfəs/; meaning "before Saurolophus", in comparison to the later dinosaur with a similar head crest) is a genus of hadrosaurid (or duck-billed) dinosaur from the Late Cretaceous of North America. It is known from the remains of at least 25 individuals belonging to two species, including skulls and skeletons, but it remains obscure. Around 9 m (30 ft), its fossils have been found in the late Campanian-age Upper Cretaceous Dinosaur Park Formation in Alberta, and the roughly contemporaneous Two Medicine Formation in Montana, dating to around 75.5-74.0 million years ago. Its most recognizable feature is a small solid crest formed by the nasal bones, sticking up in front of the eyes.

The type species is P. maximus, described by American paleontologist Barnum Brown of the American Museum of Natural History in 1916. A second species, P. blackfeetensis, was described by Jack Horner of the Museum of the Rockies in 1992. The two species were differentiated mainly by crest size and skull proportions.