So why hasn't Tyrannosaurus been renamed Manospondylus?

27th August 2002

Question

The single decrepit vertebra named Manospondylus gigas by Cope in 1892 is now recognised as belonging to Tyrannosaurus rex, which wasn't named until 1905. So you'd think that the rule of priority (see ``Why is ``Brontosaurus'' now called Apatosaurus?'' ) would mean that the older name has priority. Instead of saying ``Well, we clocked the T. rex at thirty-two miles an hour'', Dicky Attenbrough would have had to say ``Well, we clocked the M. gigas at thirty-two miles an hour'', which doesn't have the same ring.

So why has everyone's favourite dinosaur name survived?

Answer

Until 31st December 1999, the answer to this would have been rather vague - murmurings to the effect that the Manospondylus vertebra is insufficiently diagnostic: it doesn't have any features that can be used to distinguish it from other tyrannosaurs. But you could ask how, in that case, we're so sure that the vertebra is actually T. rex.

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 ^[1] 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.

Phew.

Notes

[1] 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]

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