Dinosaur scale thread

[Dinoguy2]

I think Dinoguy2 mentioned that the life position of the bones of dinosaurs couldn't be fully known, particularly for example the position of the neck.  So the length would be measured as if the animal's bones were in a straight line on the ground.  It would be increasing the length of the animal from the length when it was alive, but it would be consistent with the length estimates I tend to see for dinosaurs compared to size charts with rigorous reconstructions of the animal.  The length estimates tend to be longer than the reconstructed animals.

Yeah, the 'length' will be seriously inflated if measured that way. There's a big difference between the length of the animal from front to back, and the length of the vertebral column + skull. Here's a diagram I created to compare three different ways of measuring the 'length' of a familiar modern animal.



A is the length of the animal from front to back.
B is the length of the spine + skull, as measured in a straight line.
C is the length of the spine + skull, as measured along the dorsoventral curvature.

The numbers in black give the significantly different lengths of the lines (in pixels): C > B > A.

I understand the reason for calculating C for a scientific description, but we have to be careful not to conflate that measurement with the front to back length of the animal (A). It might work out for some groups, but it will be way off for others. In the giraffe, C is a whopping 40% longer than A. So, if length estimates for dinosaurs (on, say, Wikipedia) are uniformly calculated by method C, we need to treat the measurements with caution, and measure our toys using the same metric (if that's even possible, since the 'spine' measurement is inside the toy). The best we can measure accurately would be B. If they are not uniformly calculated by method C or the method is not made explicit, then we need to treat our scale calculations with caution.

As I've often said, the solution to this problem is to not measure length at all. Length is an estimate. Whenever possible we should measure a rigid element to calculate scale. The trunk length suggestion above is a decent one, though complicated by differing guesses about shoulder girdle placement. I usually use skull length if available. That has it's own complications about how exactly to measure the skull, but the error margin is much less significant for toy-sized things. For me, subjectively, the head is also the "personality" of the figure. If I put a human for scale next to a model, and the model is mis-scaled, it will seem "wrong" if the head size looks significantly different from known skulls. Failing skull length, I usually try to estimate femur length on the model as best I can. Not usually too hard to figure where the hip socket would be and measure to the knee.