Edmontosaurus

Edmontosaurus ( ) (meaning "lizard from Edmonton"), often colloquially and historically known as Anatosaurus or Anatotitan (meaning "duck lizard" and "giant duck"), is a genus of hadrosaurid (duck-billed) dinosaur. It contains two known species: Edmontosaurus regalis and Edmontosaurus annectens. Fossils of E. regalis have been found in rocks of western North America that date from the late Campanian age of the Cretaceous period 73 million years ago, while those of E. annectens were found in the same geographic region from rocks dated to the end of the Maastrichtian age, 66 million years ago. Edmontosaurus was one of the last non-avian dinosaurs ever to exist, and lived alongside dinosaurs like Triceratops, Tyrannosaurus, Ankylosaurus, and Pachycephalosaurus shortly before the Cretaceous–Paleogene extinction event.

Edmontosaurus included two of the largest hadrosaurid species, with E. annectens measuring up to in length and weighing around in average asymptotic body mass. The exceptionally large specimens of E. annectens measured around long and weighed around . Several well-preserved specimens are known that include numerous bones, as well as extensive skin impressions and possible gut contents. Edmontosaurus is classified as a genus of saurolophine (or hadrosaurine) hadrosaurid, a member of the group of hadrosaurids that lacked large, hollow crests and instead had smaller, solid crests or fleshy combs.