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Re: Lack of Running Giant Theropod Tracks

Ok first off I can not seem to find a track map of the Glen Rose
tracks that you are talking about on the Internet I know I have it in
a book which happens to be at home and not where I am. All I am
finding is oblique angle photos of the site which makes it really hard
to re-familiarize myself with it (ie take what I say with a grain of
salt). Now personally I do not believe that the allosaurid trackway
(ichnogen. Irenesauripus if I remember correctly) is doing anything
"weird" I suspect that the missing print is just missing; it happens,
its annoying but it happens. As I said I can not find a track map but
the toes in the photos I can find look to be unchanged. If the animal
hopped in order to keep pace we would expect a change in the
divarication of digits in order for it to keep balance (and if you do
not believe me we have a trackway in Canada that shows "weird"
unbalancing behaviour that demonstrates this). You can even experiment
at home; take off your shoes, get up, walk on the balls of your feet
(pretend you are digitigrade) and hop. I suspect that your grate
changed (either coming down on your whole foot or your stride length
changed) and you are relatively tiny compared to something like

There is a trackway in Oxfordshire England (several references) that
might be a transition from a walk to a "run" of something like
Megalosaurus, though I seem to remember hearing that there was some
evidence it could just be a walking trackway with missing prints.

Then again I'm working on the ichnogen. Tetrapodosaurus so what do I
know for theropods.
  -Tyler Shaw

On Fri, Nov 26, 2010 at 3:00 PM, Sim Koning <simkoning@msn.com> wrote:
>  Unless I missed a major discovery somewhere, we have yet to find a trackway 
> that proves that giant theropods could run. What about the Paluxy River 
> Acrocanthosaur/allosaurid trackway that is "missing" a footprint on one side? 
> It is ulikely that the Acro was hanging onto the side of the sauropod, since 
> there is no change in the sauropod's gate, and there is no distortion in the 
> "hopping" print as one might expect. If the Acrocanthosaur (or similar 
> allosauroid) was "skipping" to keep pace, that would mean this huge animal 
> hopped on one foot (both feet were in the air at one point). Doesn't this 
> trackway then demonstrate that at least this theropod had leg muscles strong 
> enough to propel it into an arial phase in its stride and was therefore 
> capable of running? How long was the hop length? Couldn't you use the "hop" 
> length to calculate the force needed to propel a 4 to 6 tonne animal through 
> the air (on one foot) for that distance and then use that data to help 
> calculate pote!
>  ntial run speed? I'm sorry if this has been brought up already. I checked 
> the list and couldn't find much on this subject beyond paper requests.
> Simeon Koning