Expert: David Prus - 10/24/2009

Question
hi-recently in the online new it said that some experts think triceratops and torosaurus are the same. what would your views on this be if you no of this information?
generally speeking i have seen the skeleton of triceratops and some photos of both and they dont look that similar to be called the same type or such
next question-is the species of tyrannosaurus -i have seen 2 types of the skeleton of and the american museum type is slighty bigger bones despite the fact that stan the rex  is called the second largest-however i know more larger undescribed specimens have been discovered -what types are the second and third largest tyrannosaurus? thanks

Answer
The scientific community is rightly skeptical about the Torosaurus=Triceratops idea. They're very similar genera, but are definitely different. There's simply no real basis for the claim. Their skeletons are about as different as the two kinds of elephants today-they're closely related, but inexorably different.

I think you're seeing sexual dimorphism at work. Apparently, female Tyrannosaurs were more robust and larger than the males like alligators and birds of prey.

Largest T.Rex specimens:
Sue-I live in Chicago, and so I'm pretty familiar with this beauty
Stan-at the Museum of the Rockies. It's pretty big, but it's a male, and so more gracile than Sue or the two American museum specimens
the American Museum specimen-I've seen it. Large and robust, scientists suspect it was a female,
The other American specimen, now in London-I have not seen this one, but I suspect it's very similar to the New York specimen
Scotty-gender unknown, but supposed to be very large. In Royal Saskatchewan Museum. Not mounted yet, and a lot is unknown about this specimen.

I hope this helps.