In 1900, fossil hunter Barnum Brown found the partial remains of a large meat eating dinosaur in Eastern Wyoming. Originally called Dynamosaurus imperiosus ("mighty imperial lizard"),by Barnum's backer Henry Fairfield Osborn, who later changed the name to Tyrannosaurus rex. However this was not the only change of name that the world's most famous monster had been through, although it took nearly a century for the truth to finally come out. To find out why we have to go back to the heady days of the Bone Wars. From 1870's through to the 1890's palaeontology in the American west was dominated by the intense rivalry between Othniel C. Marsh and Edward Drinker Cope. Consensus among historians traces the origins of their feud to an incident in 1868. Cope was working on a strange fossil sent to him from Kansas by a military doctor. Naming the specimen Elasmosaurus he placed its skull on the end of its short tail,rather than its long neck. When he discovered this error, Marsh (reportedly) humiliated Cope by pointing it out in public, at which point Cope tried to buy (and destroy)every copy of the scientific journal in which he had published his incorrect reconstruction. From that point on the two scientists were forever trying to outdo each other, going to great lengths to disinter and name fossils under the others nose. At this time numerous new species of dinosaurs were being discovered all the time (many during excavation work on the Transcontinental Railroad). During this productive, if chaotic period it is no surprise that sometimes discoveries would go missing. One such example was in 1892 when Edward Drinker Cope lost two vertebrae bones belonging to a creature he had named Manospondylus gigas. Cope believed they were from an "agathaumid" or ceratopsid dinosaur. These were plant-eating dinosaurs often with huge horns and bony neck frills of which Triceratops is probably the most famous example. However in 1917 Henry Fairfield Osborn remarked on the similarity of Manospondylus' one remaining fossil and those of a certain late Cretaceous predator. Somehow this slipped beneath the palaeontological radar. Eventually in June 2000 the Black Hills Institute found the exact location of the original Manospondylus discovery. There they found more remains, and realised that they were identical to fossils of Tyrannosaurus rex-no less! Manospondylus should have become the new name because it was officially described over a decade prior to T-rex, this is the reason why we now call Brontosaurus by the name Apatosaurus. However, faced with the prospect of redesignating the 'King of the Tyrant Reptiles' with a name that means 'giant porous vertebrae', the powers that be changed the rules on naming monsters instead: Under the new rules if a dinosaur name was presumed valid in at least 25 works and published by 10 authors over a period of 50 years then it could not be replaced by one that was considered invalid (due to diagnostic issues, for example) during that time. So T-Rex got to keep his name for another 65 million years... http://www.dinochecker.com/dinosaurs/TYRANNOSAURUS http://dinosaurs.about.com/od/dinosaurdiscovery/a/bonewars.htm http://www.dinochecker.com/dinosaurs/MANOSPONDYLUS