So why has everyone's favourite dinosaur name survived?
The truth is, it's hard to avoid the conclusion that T. rex was just too damned cool to change, so everyone sort of looked the other way when the idea of synonymy came up, and changed the subject.
Fortunately, the problem has now gone away forever. As of 1st January 2000, a new ICZN ruling has come into effect, saying that a name that's been considered valid for fifty  years can't now be replaced by one that's been considered invalid during that time. So we can shout ``Manospondylus is Tyrannosaurus'' all we want, and the name will still remain safe for democracy.
 Or it might be a hundred years, I'm not sure. I made a genuine attempt to find out the duration, but it was stymied by the rather odd ICZN policy which considers its decisions to be trade secrets which you're only allowed to know if you pay them. See http://www.museum.unl.edu/research/systematics/Orti/ICZN-changes.html for more information. [back]