The first remains of tyrannosaurids were uncovered during expeditions led by the Geological Survey of Canada, which located numerous scattered teeth. These distinctive dinosaur teeth were given the name "Deinodon" ("terrible tooth") by Joseph Leidy in 1856. The first good specimens of a tyrannosaurid were found in the Horseshoe Canyon Formation of Alberta, and consisted of nearly complete skulls with partial skeletons. These remains were first studied by Edward Drinker Cope in 1876, who considered them a species of the eastern tyrannosauroid "Dryptosaurus". In 1905, Henry Fairfield Osborn recognized that the Alberta remains differed considerably from "Dryptosaurus", and coined a new name for them: "Albertosaurus sarcophagus" ("flesh-eating Alberta lizard"). Cope described more tyrannosaur material in 1892, in the form of isolated vertebrae, and gave this animal the name "Manospondylus gigas". This discovery was mostly overlooked for over a century, and caused controversy in the early 2000s when it was discovered that this material actually belonged to, and had name priority over, "Tyrannosaurus rex".