For a given population, if you have a large enough sample of shells, you can
calculate the mean & the standard deviation (SD) & then assume that the
maximum attainable size would be about (mean + 3xSD). This follows from the
properties of a normal distribution: the probability of encountering
variants more than 3 standard deviations on either side of the mean are
exceedingly small (you would need thousands of specimens before you might
find one).

But, in a different population of the same species, the mean & the SD could
be different, which would make the maximum or minimum sizes that one is
likely to find also different.

Other than that there is no method of accurately predicting the max or min
size of a species from evolutionary considerations except that one can
derive approximate size limits based on surface area-volume or weight
considerations. For example, there can't be giant insects, because their
tracheal system wouldn't be efficient to deliver enough oxygen.

Hey, I should write about this on my blog.

Aydin
snailstales.blogspot.com


On Wed, 4 Jun 2008 13:35:04 -0300, Ross Mayhew <[log in to unmask]> wrote:

...
>
>My questions is: is there any way to calculate what is the "probable"
>maximum attainable size for a given species, within normal, natural
>parameters of genetic and environmental factors (obviously you could in
>theory do selective breeding in a protected situation, and enhance
>growth by manipulating environmental variables, but that would be a
>different matter entirely!)?  Have any studies been done along these
>lines?
>
> From an almost-warm and almost-sunny New Scotland,
>Ross Mayhew.
>http://www.schnr-specimen-shells.com/
>
>----------------------------------------------------------------------
>[log in to unmask] - a forum for informal discussions on molluscs
>To leave this list, click on the following web link:
>http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1
>Type your email address and name in the appropriate box and
>click leave the list.
>----------------------------------------------------------------------

----------------------------------------------------------------------
[log in to unmask] - a forum for informal discussions on molluscs
To leave this list, click on the following web link:
http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1
Type your email address and name in the appropriate box and
click leave the list.
----------------------------------------------------------------------