Re: Precision

[GSP1954@aol.com]

The way to determine what mass estimates are correct for a given specimen is 
easy enought. Simply treat my mass estimates as though they are those of God. 
Since there aren't any of those anyway one might as well. 

Take Brachiosaurus, specifically the mounted SII. The old ~80 tonne mass 
estimates were based on a commercial model that was inaccurate, bloated, and 
probably not the correct scale either. The skeletal restoration published by 
Janensch is also overly large, especially in the length of the dorsal series. 
Same 
for the mounted specimen, in which the actual and fragile dorsals were replaced 
by plaster models that are too long. Judging from careful a skeletal 
restoration based on the actual remains the mass could not have been much below 
30 t, 
and very probably under 40 t, my restoration has it around 32 t. There are 
bones in the collections that are larger than the mounted skeleton. So there 
probably are heavier individuals known. But we have to be careful. The 
dimensions 
of individual bones relative to mass can very a substantial amount, so even if 
a femur is say 10% longer than another it does not establish that the longer 
femur came from the heavier individual, or even if it is heavier, that it is 
by 10% cubed. Using skull dimensions is especially unreliable. The only way to 
really compare the mass of individuals is if a reasonable amount of the 
skeleton is available. 

GSPaul