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Re: Acrocanthosaurus atokensis locomotion



James Farlow Wrote :

<< Mean trackway footprint lengths at the F6 Ranch site
ranged from 29 cm to 47 cm. There were 15 trackways for
which I estimated trackmaker speed using the Alexander
equations. Most of them suggested dinosaurs in no
particular hurry, but three of them yielded estimated speeds
of 8-12 m/s. The largest animal of the three (with an
estimated speed of
11-12 m/s) had a mean footprint length of 38 cm. This could
very well have been an immature individual of
_Acrocanthosaurus_, but it could just as easily have been
some other kind of theropod.>>

In another post, I think Tom Holtz stated that it was
possible to get the weight and hip height of the individual
from a track. Has there been any attempt to do so with the
11-12 m/s trackway ? And do you think that an individual
with a 38 cm footprint would be *almost* fully grown ? (Just
reffering to phalanges lenght in another post)

Tom Holtz Wrote :

<< As Jim Farlow has (just) noted, the highest speeds from
that site were not from a full grown _Acrocanthosaurus_;
they were from either a young _Acro._ or somebody else. I
suspect that a young leggy _T. rex_ would likely yield
similar if not greater speeds.>>

Yeah, and even there, it doesn't mean it was moving anywhere
near it's top speed ... of course.

I Wrote :

> >If you ask me, Allosaurus would beat the living crap outa
> >all those three in a race. Acrocanthosaurus would be tied
> >with _Allosaurus_, T.Rex would come a conciderable margin
> >behind and Both _G.carolinii_ & _C.saharicus_ would end up
> >few steps behind ...

HT replied :
<< If we threw *Albertosaurus* into the mix, I'll bet your
twenty it'll win by a considerable margin.>>

Most likely. But it depends on which _Allosaurus_ where
talking about here. If we're talking about _A.fragilis_,
don't forget it was a lighter animal than _A.sarcoghagus_.

Tom Holtz Wrote :

<< Actually, by "walking on their toes" (i.e., digitigrade
stance) we really mean "metatarsals do not contact the
ground except at the metatarsophalangeal joint". In fact,
in gross observations, fast runners typically have shorter
toes than slow plodders.>>

So, for example, that would mean that the NCSM individual
would leave footprints of less than 50 cm ?

And :

<< ne important thing to remember here: elephants do not run
(at least by the old definition; as Hutchinson has pointed
out, it will be difficult to test an elephant on a force
plate... :-), they just walk really fast. John is actually
investigating elephant locomotion.>>

They don't do an aerial phase at such speed ... Okay. Has
there been any confirmation (12 mph by GSP) of the 25 mph
charging speeds for the elephant ?

Thomas Miller

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