[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: T.rex needs a diet!



On Sat, Oct 15, 2011 at 7:43 PM, Vivian Allen
<mrvivianallen@googlemail.com> wrote:
> I should clarify - I think the mass estimates based on bone scaling
> are incorrect (I am biased towards volumetric reconstructions,
> though). But the fact that the bone scaling studies do seem to be
> underestimate mass is interesting in itself - i.e., rather than the
> thinner/weaker bones (from whatever indicator they were using. Cortex
> area?) of dinosaurs suggesting they were a lot lighter, it might
> instead be that they had, well, thinner, weaker bones. Or very
> different bone loading, as you said. Volumetric mass estimates gives
> you a more-or-less independent variable to analyse the differences in
> the mass vs. bone geometry relationship, so with enough volumetric
> estimates you could go back and make a dinosaur curve to compare to
> the mammalian one. Be a good study!
>
> Viv

Yeah, that way it makes sense... I should get more sleep. Sorry!
I suspect that run-of-the-mill dinosaurs had lower bone loadings, and
I think my SVP talk will show why.
H

___________________________________
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 Caeser






>
> On 15 October 2011 18:49, Heinrich Mallison
> <heinrich.mallison@googlemail.com> wrote:
>>> The disagreement between volumetric estimates of mass and estimates
>>> based on scaling of bone dimensions is interesting, though.
>>
>> To me, it is not. Two reasons:
>> 1) scaling is either done by using mostly mammal data. Dinosaurs are
>> fundamentally different in their body architecture from mammals. Their
>> locomotion, accordingly, must have been quite un-mammalian, with
>> forces differently created and distributed. Scaling on this basis = No
>> go!
>> 2) or scaling is done based on monitors, birds and one or two other
>> values from crocs, then extrapolating to the fare thee well. Birds are
>> fundamentally different in body shape from non-Avialae, and crocs are
>> non-endotherm and non-cursorial. The other critters in the database
>> are between one and three orders of magnitude smaller than your
>> average large theropod or sauropod. This is not going to work either.
>>
>> What we need to do is volumetric models, with the soft tissues modeled
>> according to extant animals (see, e.g., Allen et al 2009). Anything
>> else, well - apples and pears. Sadly, we are in very short supply of
>> very large, terrestrial, cursorial, tailed animals.
>>
>> H
>> ___________________________________
>> 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 Caeser
>>
>>
>>
>>
>> On Sat, Oct 15, 2011 at 5:52 PM, Vivian Allen
>> <mrvivianallen@googlemail.com> wrote:
>>> Oh well, that's what happens when these so-called "scientists" apply
>>> the so-called "scientific method" to "develop and test" such so-called
>>> "hypotheses"...
>>>
>>> The disagreement between volumetric estimates of mass and estimates
>>> based on scaling of bone dimensions is interesting, though. The most
>>> straightforward synthesis, assuming both datasets are accurate (and I
>>> have no reason to suspect otherwise), is that dinosaurs may have had
>>> lower safety factors than mammals of equivalent size.
>>>
>>> On 15 October 2011 17:40,  <MKIRKALDY@aol.com> wrote:
>>>> Only two years ago, dinosaurs were smaller than "scientists"  thought:
>>>>
>>>> http://www.sciencedaily.com/releases/2009/06/090621195620.htm
>>>>
>>>> Mary
>>>> ----------
>>>>
>>>> In a message dated 10/13/2011 1:28:21 P.M. Eastern  Daylight Time,
>>>> birdbooker@zipcon.net writes:
>>>> HI  ALL:
>>>> FYI:
>>>>
>>>> http://www.livescience.com/16524-rex-dinosaur-weighed.html
>>>>
>>>> sincerely
>>>>
>>>> Ian  Paulsen
>>>> Bainbridge Island, WA, USA
>>>> Visit my BIRDBOOKER REPORT blog  here:
>>>> http://birdbookerreport.blogspot.com/
>>>> --
>>>>
>>>>
>>>
>>
>