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RE: Evolution of tyrannosauroid bite power



Unfortunately, your carcass-pumping hypothesis can not be verified.
Smith and I at least constrained our interpretation to  what can be
verified by others. 

Some constraints have to be set with speculation, otherwise we make a
mockery of science: We might as well say that T rex used its arms to
build an advanced civilization and the lack of artifacts is simply
because we haven't yet found them, not that they don't exist. 

Kenneth Carpenter, Ph.D.
Curator of Lower Vertebrate Paleontology & Chief Preparator
Department of Earth Sciences
Denver Museum of Nature & Science
2001 Colorado Blvd.
Denver, CO 80205 USA

Office phone: 303-370-6392
Museum fax: 303-331-6492
---------------------------------------------------------------
For PDFs of some of my publications, as well as information of the Cedar
Mountain Project:
https://scientists.dmns.org/sites/kencarpenter/default.aspx
(if you have problems with the link, cut and paste it into the browser
address bar)
-----------------------------------------------------------------
The scientific method is a myth:
http://www.dharma-haven.org/science/myth-of-scientific-method.htm
--------------------------------------------


-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu] On Behalf
Of ptnorton
Sent: Tuesday, January 01, 2008 1:41 PM
To: d_ohmes@yahoo.com; dinosaur@usc.edu
Subject: Re: Evolution of tyrannosauroid bite power

I never said anything about the arm getting close to the mouth (see my
earlier post). Carcass lifting is conjectured as a dominance display
behavior that is not related to eating per se. Lowering the torso
sufficiently close to the ground for the arms to clasp onto a chunk of
meat
is well within the published range of motion for T. rex hips, legs and
neck
and lifting that chunk of meat, within the constraints outlined by
Carpenter
and Smith (sorry about that omission), is biomechanically possible.

PTJN

----- Original Message ----- 
From: <Ken.Carpenter@dmns.org>
To: <ptnorton@suscom-maine.net>; <d_ohmes@yahoo.com>; <dinosaur@usc.edu>
Sent: Tuesday, January 01, 2008 3:30 PM
Subject: RE: Evolution of tyrannosauroid bite power


Good, then you also know we also stated that "we also believe that, as
with most predators, T rex was opportunistic and would have scavenged
when given the opportunity." Considering the very limited range of
motion of the arm in a forwards direction (Fig. 14 Carpenter, K. 2002.
Forelimb biomechanics of nonavian theropod dinosaurs in predation.
Senckenbergiana Lethaea 82: 59-76), the snout would need a hole to
accommodate it. This limited range of motion (hence why the snout would
hinder carcass lifting) is better shown in Fig. 1 of the paper with
Lipkin in the T rex book: the arm can not get anything remotely near the
mouth.

Kenneth Carpenter, Ph.D.
Curator of Lower Vertebrate Paleontology & Chief Preparator
Department of Earth Sciences
Denver Museum of Nature & Science
2001 Colorado Blvd.
Denver, CO 80205 USA

Office phone: 303-370-6392
Museum fax: 303-331-6492
---------------------------------------------------------------
For PDFs of some of my publications, as well as information of the Cedar
Mountain Project:
https://scientists.dmns.org/sites/kencarpenter/default.aspx
(if you have problems with the link, cut and paste it into the browser
address bar)
-----------------------------------------------------------------
The scientific method is a myth:
http://www.dharma-haven.org/science/myth-of-scientific-method.htm
--------------------------------------------


-----Original Message-----
From: ptnorton [mailto:ptnorton@suscom-maine.net]
Sent: Tuesday, January 01, 2008 1:21 PM
To: Ken Carpenter; d_ohmes@yahoo.com; dinosaur@usc.edu
Subject: Re: Evolution of tyrannosauroid bite power

Yes I did "bother" to read the paper, and having looked at the range of
motion involved in the carcass lifting behavior (not dissimilar to
bending
down to take a drink of water or bending down to take a bite out of a
carcass lying on the ground), I disagree with the idea that any
excavation
would be necessary.

PTJN.
----- Original Message ----- 
From: <Ken.Carpenter@dmns.org>
To: <ptnorton@suscom-maine.net>; <d_ohmes@yahoo.com>; <dinosaur@usc.edu>
Sent: Tuesday, January 01, 2008 3:13 PM
Subject: RE: Evolution of tyrannosauroid bite power


I assume that Carpenter 2001 actually refers to Carpenter AND SMITH
2001. Considering the limited range of motion of the forelimb of T rex,
even I have to admit it could not get its hands down on a carcass to
lift it unless it first dug a hole with its feet to accommodate its
snout. Sorry, but I am not buying that behavior. I assume you actually
bothered to read the paper available at my website below? If so, then
you know the full argument we presented.

Kenneth Carpenter, Ph.D.
Curator of Lower Vertebrate Paleontology & Chief Preparator
Department of Earth Sciences
Denver Museum of Nature & Science
2001 Colorado Blvd.
Denver, CO 80205 USA

Office phone: 303-370-6392
Museum fax: 303-331-6492
---------------------------------------------------------------
For PDFs of some of my publications, as well as information of the Cedar
Mountain Project:
https://scientists.dmns.org/sites/kencarpenter/default.aspx
(if you have problems with the link, cut and paste it into the browser
address bar)
-----------------------------------------------------------------
The scientific method is a myth:
http://www.dharma-haven.org/science/myth-of-scientific-method.htm
--------------------------------------------


-----Original Message-----
From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf
Of ptnorton
Sent: Tuesday, January 01, 2008 1:07 PM
To: don ohmes; dinosaur@usc.edu
Subject: Re: Evolution of tyrannosauroid bite power

Don Ohmes wrote:

> However, Carpenter, et al, have definitely shown that the arms of the
big
> old thing were such that they would have been more useful to "T. rex
the
> predator", than to "T.rex the scavenger". <

Carpenter's 2001 paper was a nice piece of work as far as evaluating the

strength of T. rex arms, but with all due respect I suggest that his
conclusion that T. rex was therefore predator does not logically follow
from
his findings.  I mentioned the "carcass lifting" hypothesis earlier
because
it offers an explanation that is consistent with all the evidence but
does
not require predation or prey grappling as a premise. Let me say that I
have
no idea if T. rex engaged in carcass lifting or not, but in principle it
can
not be ruled out on the evidence and is therefore an equally plausible
explanation of forelimb function.

> So anyhow, on to my main question -- for those that _do_ accept that
> Carpenter, et al, has supplied definitive proof of a predatory
lifestyle;
> can Carnotaurus and others with extremely-dinky-and-also-very-weak
arms
> now be safely accused of being 'dumpster-divers'? <

Before speculating about other types of dinosaurs, those folks must
first
explain how the premise that an animal possessing a M. biceps capable of

generating a force of 1955.3N compels the conclusion that that animal
was a
predator.

PTJN