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Re: Another PLoS One comment



Let me add that Jaime's email give my work more credit than it
deserves in relation to the paper her didn't explicitly cite in the
body of the email (but did list in the ref list): Allen et al. 2009!
They give percentage ranges for the difference between skeletal extent
and soft tissue extent in extant animals, and that is the best data to
go on (as the Hutchinson group has been doing).

Allen, V., Paxton, H. & Hutchinson, J. R. 2009. Variation in center of
mass estimates for extant sauropsids, and its importance for
reconstructing inertial properties of extinct archosaurs. _The
Anatomical Record_ 292:1442–1461
___________________________________
Dr. Heinrich Mallison
Abteilung Forschung
Museum für Naturkunde - Leibniz-Institut
für Evolutions- und Biodiversitätsforschung
an der Humboldt-Universität zu Berlin
Invalidenstrasse 43
10115 Berlin
Office phone: +49 (0)30 2093 8764
Email: heinrich.mallison@gmail.com
_____________________________________
Fere libenter homines id quod volunt credunt.
Gaius Julius Caesar



On Fri, Jan 20, 2012 at 11:52 PM, Jaime Headden <qi_leong@hotmail.com> wrote:
>
>   This response doesn't appear to account for the recent revisions in 
> estimating masses of particular muscles, especially the mCFL (Mallison, 2010, 
> 2011; Persons & Currie, 2011a,b). Such estimates for some taxa are woefully 
> under-estimated, and this can be accounted for by over-leaning the bodies. 
> Your reply does not mention these analyses, possibly because, as Hutchinson 
> et al. (2011) state, some are based on fitting skin to a near-skeletal model 
> of a tyrannosaur, something that is akin to the modeling proposed by Paul 
> (2000). The mCFL represents by itself a substantial amount of mass in the 
> body and influences CoG and thus walking/running motion dynamics and mass 
> directly. Even if Hutchinson's robust mass estimates, using a "inflated" 
> envelope around the body, are massively over-proportioned, one can take the 
> numbers used to generate the envelope and slim it down directly; this cannot 
> be done with the sculpted-model/immersion technique favored by Paul, which 
> also introduces a massive amount of bias which can produce error. 
> Computational analyses, as in Hutchinson, Mallison, Persons, and Allen's 
> works, produce estimates based on mathematic models, and can be directly 
> tweaked, but one must _estimate_ the relative mass in a clay or plastic model 
> for the immersion technique, and revise the physical model itself, 
> compounding human bias in the error margin. I think it is (and has been) far 
> beyond the time to retire the immersion model as useful when far better, more 
> precise and easily adjustable, methods exist to estimate mass.
>
> Allen, V., Paxton, H. & Hutchinson, J. R. 2009. Variation in center of mass 
> estimates for extant sauropsids, and its importance for reconstructing 
> inertial properties of extinct archosaurs. _The Anatomical Record_ 
> 292:1442–1461.
> Hutchinson, J. R., Bates, K. T. & Allen, V. 2011. *Tyrannosaurus rex* redux: 
> *Tyrannosaurus* tail portrayals. _The Anatomical Record_ 294:756-758.
> Mallison, H. 2010. The digital *Plateosaurus* I: body mass, mass 
> distribution, and posture assessed using CAD and CAE on a digitally mounted 
> complete skeleton.
> _Palaeontologia Electronica_ 13(2):8A.
> Mallison, H. 2011. Defense capabilities of *Kentrosaurus* aethiopicus Hennig, 
> 1915. _Palaeontologia Electronica_ 14(2):10A.
> Paul, G. S. 2000. Limb design, function and running performance in 
> ostrich-mimics and tyrannosaurs. _Gaia_ 15:257–270.
> Persons, W. S., IV & Currie, P. J. 2011. The tail of *Tyrannosaurus*: 
> Reassessing the size and locomotive importance of the M. caudofemoralis in 
> non-avian theropods. _The Anatomical Record_ 294:119-131.
> Persons, W. S., IV & Currie, P. J. 2011. Dinosaur speed demon: The caudal 
> musculature of *Carnotaurus sastrei* and implications for the evolution of 
> South
> American abelisaurids. _PLoS ONE_ 6(10):e25763.
>
> Cheers,
>
>  Jaime A. Headden
>  The Bite Stuff (site v2)
>  http://qilong.wordpress.com/
>
> "Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
>
>
> "Ever since man first left his cave and met a stranger with a
> different language and a new way of looking at things, the human race
> has had a dream: to kill him, so we don't have to learn his language or
> his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
> Backs)
>
>
> ----------------------------------------
>> Date: Fri, 20 Jan 2012 09:24:01 -0500
>> From: gsp1954@aol.com
>> To: dinosaur@usc.edu; vrtpaleo@usc.edu
>> Subject: Another PLoS One comment
>>
>>
>> I've posted another comment on Tyrannosaurus mass estimates addressing a 
>> number of issues at
>>
>> http://www.plosone.org/annotation/listThread.action?inReplyTo=info%3Adoi%2F10.1371%2Fannotation%2F7082d67e-9835-49bc-ad62-2b330753c355&root=info%3Adoi%2F10.1371%2Fannotation%2F7082d67e-9835-49bc-ad62-2b330753c355
>>
>> I was quite surprised to realize that the Henderson & company mass estimates 
>> based on my skeletal restoration of 5027 were much higher simply because 
>> they increased the size of models.
>>
>> GSPaul
>