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Re: rearing browsers



On Tue, 23 Jul 1996 Dinogeorge@aol.com wrote:

> In a message dated 96-07-22 17:52:50 EDT, longrich@phoenix.Princeton.EDU
> (Nick Longrich) writes:
> 
> > Granted, these are BMNH models, but I'll bet if you use a more 
> > modern reconstruction, you'll get an even higher figure perhaps- 
> > Diplodocus and Stegosaurus really had very short bodies, and older 
> > reconstructions might not reflect this. 
> 
> In HISTORICAL DINOSAUROLOGY #1, I note the trend toward shortened stegosaur
> backs, which seems to have culminated with _Wuerhosaurus ordosensis_, an
> Early Cretaceous Chinese stegosaur that had just 11-12 dorsal vertebrae. It
> also seems to have had the shortest forelimbs relative to hindlimbs of any
> stegosaur. A restoration of this beast's skeleton posed bipedally will be on
> the cover of that volume when it appears this fall.

        Very interesting. McIntosh says the same happened with diplodocid 
necks- they pulled vertebrae out of the back and into the neck to get a 
longer neck. I think it looks like, from the basic body plan of the 
two groups- diplodocids and stegosaurs- (with the confusing exception of 
the neck -why wasn't it longer in stegosaurs?) that they were doing the 
same thing. Both had large, powerful tails (this could be interpreted, 
though, I'd suppose, as either a result of, or a setup for, the tail 
weaponry) often bearing elongate chevrons, very high dorsal spines, large 
powerful hindlimbs and short forelimbs, with short chests. 

Another thing to note are the figures for Triceratops- Alexander got 54% 
of the weight at the front end, which is wrong- Triceratops had a much 
larger head than was previously thought, the BMNH model
having a skull that's not large enough. But even ignoring the error, 
the animal is still frontheavy, the opposite of nearly every other 
dinosaur. Looking at the AMNH specimen, it looks as though the front 
limbs and dorsal verebrae in the front of the chest actually are thicker 
than the hindlimbs and rear dorsals- so Triceratops was really built more 
like a mammal than a dinosaur, in that respect.
Even his figures for Brachiosaurus still 
put most of the weight on the hindlimbs, although less so than in 
diplodocids.
        -nick L.