Re: New alvarezsaurid

["Jaime Headden" <jaemei@hotmail.com>]

<The keeled sternum goes back at least as far as allosaurids; the new
allosaurid at Dinosaur National Monument has a keeled sternum.>

Oh, really?

Well, this puts a new slant on things. If *Allosaurus* possessed a 
carina or keel, that means the keel did not evolve for flight, at least 
in this dinosaur (just imagine, an allosaur flapping its stubby little 
arms {in comparison to the body} as it runs, trying to get lift, jogging 
towards that cliff over there....). In birds, the keel develops the 
forward-and-down stroke of the humerus (and hence, the wing) the more 
powerful movement of the arm in general. The keel increases the normal 
flexion of the muscles attached, and thus add power to the stroke that 
existed before birds got wings. Birds just modified it for flight (that, 
or theropods modified it for...).

Now, this new Allo has the keel, you can assume that he's got strong 
arms (stronger than otherwise, any way) and without flight development 
(obviously) he used the keel for the forward-and-down stroke movement, 
which, augmented with the inward-facing variability of the hands, would 
have allowed the arms to SMACK! inward at anything between them, or to 
push backward (this could also be used as a swimming adaptation, though 
don't take my word on it).

What of other *Allosaurus* sterni? Do we have any others, or just this 
one specimen (and coudl this mean a new genus or species, rather than 
just another specimen?) Incidentally, what's the specimen number? DNM ?.

Jaime A. Headden
Qilongia

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