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Re: Dreadnoughtus weight calculation



I found GSP's post very interesting.  However, it is worth noting
that, from a historical perspective, the name _Dreadnoughtus_ is
perhaps more appropriate than GSP made out. The archetypal dreadnought
(HMS Dreadnought, launched 1906) was a product of the naval arms race
between Great Britain and Germany prior to World War I.  The
Dreadnought was part of a broader British strategy of deterrence - the
importance of having a large, powerful and technologically advanced
fleet to reinforce Great Britain's superiority at sea, rather than
deploying warships as a decisive military force.  Under First Sea Lord
Fisher, the role of the British war fleet was intended to be mostly
defensive - to protect the homeland; guard the British Empire's
strategic ports; and enforce a naval blockade against Germany should
war break out.  As it turned out, the greatest sea-born threat to
Great Britain during World War I turned out to be German U-Boats and
their unrestricted warfare against enemy and neutral shipping.  It was
this that ultimately helped draw the United States into World War I.


On Sat, Sep 6, 2014 at 12:32 PM, Ben Creisler <bcreisler@gmail.com> wrote:
> >From Greg Paul...
>
> ---------- Forwarded message ----------
> From:  <GSP1954@aol.com>
> Date: Fri, Sep 5, 2014 at 7:21 PM
> Subject: Please  forward
> To: bcreisler@gmail.com
>
>
> The lists do not seem to be accepting my posts even though I can read the
> posted messages, so please forward --
>
> The calculation that Dreadnoughtus was 65 tonnes is massively excessive.
>
> The solid black ink type skeletal restoration in the main text is badly
> misproportioned, with the vertebral series much too large relative to the
> limbs, and the body severely overbloated -- it does not even match the of 
> course
> accurate digital version of the skeleton included in the supplementary
> information. The Jackie Gleason skeletal drawing would mass something 
> approached
> 65 tonnes, the mass arrived at in the paper via humerus/femur circumferance
> calculations that are well know to be unreliable because their is so much
> variation in mass at any given combined limb circ.
>
> In elephants the constant of body mass to femur length in decameters
> squared is about 3, in the massive gigantic brachiosaurs it is 3.5 to 4 based 
> on
> the skeletons and models.  If Dread weighed 65 tonnes the constant would be
> ~9, far, far higher than in any large land animal. A correct skeletal
> restoration, based largely on the correct digital image in the
> supplementary info,
> produces a constant of 4. That means that Dread had very robust limbs for
> its mass, giving it a much higher safety factor than brachiosaurs that are
> well known for having slender limbs. In otherwords, we use the volume of the
> life version of the animal stretched over the skeleton to estimate relative
> and absolute limb strength, we never ever use limb strength to estimate mass
> because that is circular reasoning disproven by the large empirical variation
> in living animals.
>
> The Dread skeleton just is not very large. A number of sauropods had, or
> must have had, much longer femora. For example the heavily built brachiosaurs
> with femora around 2.5 m and a constant of 3.5-4 weighed 30-35 tonnes
> (that's with a rather higher specific gravity than most people tend to use 
> these
> days), so Dread with its 1.91 m femur and a mass/femur constant comes out to
> 28. The biggest known titanosaur published femur belongs to what is not
> actually Antarctosaurus at 2.3 m. That complete super titanosaur femur 
> announced
> this year I have estimated that Argentinosaurus and similar sized but more
> complete Futalognkosaurus (am using the pubis length in Lacovara et al to
> size this) at 2.4 m, with constants around 4, so these  were 50 tonners. No
> way Dread with its three quarters as long femur weighed any where close to
> those colossi.
>
> I have been at this sort of thing since the early 1980s. Here we are in the
> 2010s. There is no excuse for this. By now all researchers should know
> better than to publish masses estimated from limb strength at face value, or
> publishing sloppily proportioned skeletal restorations. Before making claims 
> of
> size it is required to use a rigorous skeletal-muscle etc. model to compare
> the volume of a particular sauropod to that of others modeled using the
> same techniques, that way it would have been obvious that not really all that
> big Dread is smaller than the Berlin Giraffatitan, much less the really
> titanic Argentinian titanosaurs. It would also be useful for reviewers to pay
> attention to these matters, since the public does not really care all that 
> much
> about the phylogenetics but does about the size. People might want to send
> the paper to me for a look at before submission. Of course had the size of
> Dread been accurately presented it would not have made it so big in the
> press. As it is the public has been misinformed about its mass by a
> factor of two
> or more, and how it is Dread is modest sized compared to the really big
> boys and girls.
>
> I will be publishing this info in the technical literature.
>
> As for the name Dreadnoughtus. Fine in terms of being big and powerful, but
> the justification for the etymology in the paper and media is technically
> and historically  errant. Dreadnoughts were not defensive ships nearly immune
> to attack. They were the offensive superpredators of their time, used to
> hunt down and destroy enemy warsahips from dreadnaughts on down -- it was
> predator versus predator, not herbivores protecting themselves from predators.
> At the same time dreadnoughts were very vulnerable to being sunk, sometimes
> very suddenly. The first dreadnought sunk, the Audacious in WW 1, was taken
> down by a single mine. Later in that war a wee torpedo boat sunk the Szent
> Istavan (that's the immobile batship that rolls over with the crew scrambling
> about on the hull). In WW II the Barham was lost to a submarine (that's the
> batship that's rapidly rolling onto its side when it blows up). A month
> later a single bomb blew up the Arizona  -- odd because the same bombs failed 
> to
> penetrate the similarly think armored decks other batships at Pearl. Two
> torpedoes from a destroyer sunk Fuso in twenty minutes. And of course the
> enormous superbattleships Yamato and  Musashi  were done in by swarms of 
> little
> Avenger torpedo planes (my uncle flew in one of those at  Okinawa, but was
> not in the attack on the  Y). All in all about a dozen and a half deadnaughts
> were lost to enemy action.
>
> GSPaul</HTML>