Prosaurolophus ‭(‬Before Saurolophus‭)

Short Info

Prosaurolophus ‭(‬Before Saurolophus‭)

Phonetic : Pro-sore-o-lo-phus.

Named By : Barnum Brown‭ ‬-‭ ‬1916

Diet : Herbivore

Size : Estimated 7.6 – 9 meters long

Type of Dinosaur : Euornithopod

Type Species : P.‭ ‬maximus‭ (‬type‭)‬,‭ ‬P.‭ ‬blackfeetensis

Found in : Canada,‭ ‬Alberta‭ ‬-‭ ‬Dinosaur Park Formation.‭ ‬USA,‭ ‬Montana‭ ‬-‭ ‬Two Medicine Formation

When it Lived : Late Cretaceous, 77-75 million years ago

Prosaurolophus (/.proUso.’ral@f@s/) is a genus that includes hadrosaurids (or duck-billed dinosaurs) from the Late Cretaceous period of North America. Although it is known from at least 25 remains, which include skulls and skeletons of two species, the exact nature of its existence remains a mystery. Its fossils are approximately 9 m (30 feet) long and were found in Alberta’s Campanian-age Upper Cretaceous Dinosaur Park Formation. They also appeared in Montana’s Two Medicine Formation, which is roughly the same time. These fossils date back to 75.5-74.0 millions years ago. The most distinctive feature of this fossil is the small, solid crest made by the nasal bones that rises in front the eyes.

Prosaurolophus maximus, Red Deer River, Alberta, collected 1921 by Levi Sternberg - Royal Ontario Museum - DSC09845Daderot, CC0, via Wikimedia Commons

P. maximus is the type species. It was first described in 1916 by Barnum Brown, an American paleontologist from the American Museum of Natural History. Jack Horner of the Museum of the Rockies described a second species, P.blackfeetensis in 1992. These two species were distinguished mainly by their skull proportions and crest size.

Barnum Brown, a well-known paleontologist, found a duckbill skull from the Red Deer River of Alberta near Steveville in 1915. In 1916, he called the specimen Prosaurolophus. Brown chose the name Prosaurolophus because it was similar to Saurolophus which he had previously described in 1912. Saurolophus had a shorter, more spike-like headcrest. Although the skull suffered from a damaged muzzle, it was accidentally reconstructed too late. However, better remains soon emerged that revealed its true form. One is a complete skull and skeleton, which William Parks described in 1924. This species is known to have twenty-five to twenty-five individuals, with seven skulls that contain at least part of the skeleton.

P. blackfeetensis is the second species. It was based on a specimen found in the Museum of the Rockies, MOR 454, which Jack Horner, a prominent paleontologist, described. The remains of at least three to four additional individuals were also found in Glacier County, Montana. The fossils of the Prosaurolophus remains were found in the bonebed, which suggests that they lived together for some time. This bonebed could be interpreted to reflect a group of animals who congregated close to a water source during drought.

Horner distinguished the two species based on the details of their crests. Horner interpreted P. blackfeetensis to have a higher, more prominent face than P. maximus. The crest migrates backwards toward the eyes during growth. Recent studies have shown that the differences are insufficient to support two species.

Source: Wikipedia