T. rex redux

[Mark Pankowski <mpankows@freenet.scri.fsu.edu>]

On Fri, 12 May 1995, Tom Holtz wrote:

> >Try looking for 'The Complete T-Rex' 1994 by John R. Horner and Don Lessem.
> >This book has all the good tyrannosaur stuff.
> 
> Well, not quite.
> 
> As I mentioned in my review of the book in this March's issue of Quarterly
> Reviews of Biology, there have been some important work on tyrannosaurs
> which didn't make it into the book, including the various isotope work on
> dinosaurs, as well as some relatively minor work on tyrannosaur foot
> biomechanics and the phylogenetic position of the Tyrannosauridae ;-)
> 
> Also, a few specimens have been found post-writing of the Complete T. rex
> (the "r" should never be capitalized, and there is no hyphen) which are
> fairly complete, including Stan.
> 
> But still, a pretty good book.

>From several responses I got on my earlier question on the two types of 
T. rexes, I know understand them to represent two sexes. Now, one more 
question that's been driving me crazy of late (clearly, I'm driven crazy 
fairly easily). In Horner and Lessem's book, "The Complete T. Rex," they 
write on page 173 (in the hardbound edition):

"Dale Russell, a Canadian dinosaur paleontologist, was the first modern 
scientist to suggest we were calling two different animals T. rex. He 
thought Osborn's names should have been kept separate. Dynamosaurus 
imperious would fit the more massive specimens like the one in Los 
Angeles; T. rex would be just the slighter ones like the skeleton at the 
Carnegie Museum."

Now, my understanding (from other parts of the book) is that the specimen 
in Los Angeles is a lightly built animal while the one at the Carnegie 
Museum represents the more massive T. rex. In other words, it's backwards 
in the quote above. Here's my question:

Just for the sake of argument, let's assume T. rex does represent two 
animals: Which is Russell suggesting gets the name 
T. rex -- the massive version or the slighter version? And which gets the 
name Dynamosaurus imperious? I'm guessing he meant the more massive 
version would be called T. rex, and the gracile version would be known as 
Dynamosaurus imperious.
(Or would whoever proves this theory get to name the "new" version?)

Of course, this all means nothing if, as I now understand, the two 
versions of 
T. rex just represent two different sexes. But, for some reason, this 
apparent mistake in the book is driving me nuts.

If anyone can answer this (possibly pointless) question, I'd be most 
grateful.

Thanks. (And thanks to all who gave me the original answer to the T. rex 
sexes question).

Mark