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Re: Meglania weighed only 1 tonne (long)



>
>Hecht (1975) examined all the remains of the giant monitor Meglania, and
>calculated the maximum dimensions and weights.  He came to the reasonable
>conclusion that the lizard weighed less than one tonne. This is in agreement
>with my model, which was proportioned after the mounted skeleton (a profile
>of which is published in Dinosaur Eggs and Babies). These mass values apply
>to the largest published remains.

New material discovered since Hecht (1975) indicates a size of
approximately 1.5 times the largest specimens Hecht got to look at. As a
linear extrapolation, that puts us in the 1.5 tonne region.

>
>Auffenberg calculated over 2.2tonnes for the same remains. However, this was
>>based on a size-mass curve for the Komodo ora that only went up to 2.5 m and
>50 >kg. If Auffenberg's estimate is correct, then the super lizard was about
>as big >as Daspletosaurus, which my model shows weighed about 2.3 tonnes. For
>some >reason some one thought comparing a lizard and a tyrannosaur was not
>useful. Why was not explained. In fact it tells us a lot. Daspletosaurus was 9
>>m long, Meglania at most only 7 m. The trunk vertebrae of the tyrannosaur
>were >110 mm long, the biggest example from the lizard was 67 mm long. The
>tyrannosaur's toe claw was 150 mm long, the largest Meglania toe claw (from
>the biggest known individual according to Hecht) was a wee little thing of 85
>mm. In all respects the skeleton of the biggest lizard was much smaller than
>the tyrannosaurs, and weighed about half as much or less.

In as much as a snake makes a lousy model upon which to reconstruct an
extinct bird, I would argue that a theropod (whose reconstructions are open
to dispute any way) would make a lousy model upon which to reconstruct an
extinct varanid lizard (a similar phylogenetic distance is required). As
such, I would tend to lead more credance to Auffenbergs estimates.

>
>Those who wish to argue that Meglania weighed well over one tonne, please
>make a model and publish it first.
>

Rich and Hall (1984) in Vertebrate Zoogeography and Evolution in
Australasia detail how the reconstruction of Megalania was produced. This
is the reconstruction tha Greg keeps refering to and it is 5.5 metres long,
not 7 metres. Of interest, they note that many dimensions are not linear,
but indicate that at a certain length, growth slowed and bulk took off. A
similar situation as occurs in really big crocs. An 18 foot croc usually
weighs half as much again as a 15 foot croc. Now, if the 5.5 metre
Megalania (based on Hecht's material) clocks in at 1 tonne, it is quite
concievable that elements that are 1.5 times that size come from an
individual of considerably greater mass, not a linear 1.5 tonnes, but
something approaching 2 tonnes or more. Again, the material is fragmentary
and the extrapolations are tentative, but the ball park figure is way in
excess of 1 tonne as the upper limit for Megalania mass.

Cheers, Paul

pwillis@ozemail.com.au