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The feet of the AMNH _T. rex_



At 06:15 PM 3/10/99 -0000, Jeffrey Martz wrote:

>       P.S. What's wrong with the American Museum's T.rex feet?

Do you want the short version, the medium version, or the really long
version where I bring aristogenesis and Lord Kelvin into it...?

Short version:
The foot is a reconstruction, and is non-arctometatarsalian.

Medium version:
AMNH 5027 had no hindlimbs, so Osborn used casts of the type of _T. rex_.
However, the foot of the type of _T. rex_ didn't have a complete metatarsus
(in particular, it only had the distal parts of mtIII).  Since he didn't
know what a real tyrannosaurid foot looked like, Osborn restored the
metatarsus after _Allosaurus_ (the best known large theropod at the time),
resulting in a foot which is too short and way too broad for the real thing.
Also, the type specimen is a robust morph, while AMNH 5027 is a gracile
morph, so the legs are too massive for the individual in question.

As is well known, Osborn restored AMNH 5027 with too many caudal vertebrae,
after _Allosaurus_.  What's more, most of the chevrons were missing from
AMNH 5027, and Osborn restored these after _Allosaurus_.  However, anyone
going to the AMNH should turn around and look at the _Gorgosaurus_ specimens
to see what real tyrannosaurid chevrons are like.

The new 1990s mount of AMNH 5027 fixed the caudal vertebrae problem, but
left the hindlimb and chevron problems.

I'll leave the really long version for another time...

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:tholtz@geol.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661