Turtle Shell Thickness

[Hipockets]

I was wondering , if the thickness of fossil turtle shell is relative to the size of the turtle, is there a generic formula for estimating how large the turtle would be based on shell thickness of a fragment ?

[indominus rex]

@Tidgy's Dad

[Tidgy's Dad]

I doubt there's a formula as the comparative thickness of the shell is dependent on many factors and varies from species to species, from extremely thick in some tortoises and land turtles to thinner softer sea turtles and just thickened skin in some soft shelled turtles. In the painted turtle,  Chrysemys, for example the shell accounts for about a third of the total body mass,. 

The thickness of the shell also varies at different points of the body. generally the carapace is thicker towards the front and thins towards the posterior and the plastron is thinner again, but more uniform front to back but thinner towards the centre. 

So, the short answer is "No, I don't think there can be a formula."

Diet, general health, and genetics will also play a part. 

[Hipockets]

Thank you for the quick reply. I was reading about the Coal Mine  Turtle found in 2005 in Columbia, and it raised my question. Turtle shell fragments are a common find at most of the sites I collect from. Thanks again.

[Plax]

I agree with Tidgy's Dad. If one was looking at a series of Bothremys shell frags (for instance) though, one could interpret size if measurements of complete specimens were known. This would be that a half meter long Bothremys has a specific plastron bone thickness of ???. You have that particular plastron bone so can infer the size of the complete turtle shell.

[Hipockets]

Don,  makes sense to me. So now I need to carry a micrometer to the museums that house full turtles and start a stat sheet for reference.