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

Re: New paper on pre-Archaeopteryx coelurosaurian dinosaurs



Perhaps a better way to calculate body size from the preserved bones
is to to employ Brochu's 1996 (JVP) method, which takes into account
as many homologous linear measurements as can be obtained, to
establish a geometrical mean. Nothe that this method may well not talk
to you about the actual size of the specimen, but is good to determine
relative size, which can be of use, for example, in testing the
dubious claim that Gigantoraptor is the largest theropod.

2010/10/28 Jaime Headden <qi_leong@hotmail.com>:
>
>   When dealing with something as abstract as "hip height," or "burrowing" 
> habits, one must allow themselves a lot of leeway to be totally and utterly 
> wrong. In this case, it's because relative hip height is relative itself to 
> activity and posture, and a host of other variables that assume perfect 
> understanding of relative time in a given ecology, such as how laden with 
> food or pre-nesting gravidity the given animal is, or whether this has any 
> impact.  I just find it amusing to see people debating about hip height by 
> comparing limb segment lengths, when various other factors in their biology 
> (as in cartilage extent and shape, as well as degree of cartilage in each 
> limb segment length, and/or stance configuration to projected body-mass/cog, 
> as recently detailed by Holliday et al and of course the paper cited below by 
> Dr. Baeker.  It's not that it is not productive to ask the question (it is, 
> of course it is), but that there is a reasonable conclusion with necessary 
> but missing data involved in the equation that is not used to reach said 
> conclusion.
>
> 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: Thu, 28 Oct 2010 09:24:40 +0200
>> From: martin.baeker@tu-bs.de
>> To: qi_leong@hotmail.com
>> CC: dinosaur@usc.edu
>> Subject: RE: New paper on pre-Archaeopteryx coelurosaurian dinosaurs
>>
>> Possibly the most scientific approach to this question would be to
>> look at the whole configuration space of possible leg positions, like
>> it was done by Hutchinson, Gatesy and some other guy (*cough, cough*)
>> here:
>>
>> Journal of Vertebrate Paleontology 29(2):535-544. 2009
>> http://www.rvc.ac.uk/Aboutus/Staff/jhutchinson/documents/23_000.pdf
>>
>>
>> On Wed, 27 Oct 2010, Jaime Headden wrote:
>>
>> >
>> > And depends on the level to which you will push "hip height." A shorter 
>> > tail for an oviraptorosaur, if the animal were like birds, would indeed 
>> > make the femur a far less important element of the effective limb length 
>> > (and therefore hip height). However, unlike birds, the femur is quite long 
>> > compared to the rest of the body, and we would assume it was far more 
>> > vertical than in, say, a pigeon or ostrich. As such, the effective limb 
>> > length, despite the short tail (the tail is known, it IS short) would be 
>> > closer to the total limb length than it would in a bird. Moreover, the 
>> > animal was likely tilted upwards at the hip, would places the anterior 
>> > ilium above the midlength height of the ilium, so if we really wanted to, 
>> > iliac height increases the body profile above the hip quite significantly, 
>> > unlike in, say, *Tyrannosaurus bataar.*
>> >
>> > 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: Wed, 27 Oct 2010 16:51:39 +0200
>> >> From: david.marjanovic@gmx.at
>> >> To: dinosaur@usc.edu
>> >> Subject: Re: New paper on pre-Archaeopteryx coelurosaurian dinosaurs
>> >>
>> >> Rescued from truncation:
>> >>
>> >>>> That sums to 322.4 cm (assuming totally erect hindlimb posture,
>> >>>> which of course is wrong). I can see where you'd add on a few extra
>> >>>> cm for the cartilaginous joints, but a whole 80 cm?
>> >>>
>> >>> and please keep in mind that Senter and Robins (2010) assume less
>> >> cartilage,
>> >>> so you'd have to add some cm to *G.*, too. Assuming identical limb
>> >> flexion
>> >>> angles in both taxa, *G.* stays taller.
>> >>> :)
>> >>> Heinrich
>> >>
>> >> I'd assume a bit more limb flexion in *G.*, though, because as an
>> >> oviraptorosaur it probably had a shorter tail.
>> >
>> >
>>
>> Priv.-Doz. Dr. Martin Bäker
>> Institut für Werkstoffe
>> Technische Universität Braunschweig
>> Langer Kamp 8
>> 38106 Braunschweig
>> Germany
>> Tel.: 00-49-531-391-3073
>> Fax 00-49-531-391-3058
>> e-mail
>
>