Hi Bob, I just see your post now, and thought about a couple of alternative
hypothesis:
1. Have you discarded the possibility of some kind of differential erosion
in dead specimens affecting the measures?
2. What about some kind of genetic derive? I mean something like a typhoon
killng a lot of local specimens which are replaced later in a natural way by
foreign specimens from the nearest place.
Just some ideas...

Alfonso Pina
Málaga, Spain
[log in to unmask]
www.eumed.net/malakos


----- Original Message -----
From: "Bob Dayle" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, January 18, 2003 12:47 AM
Subject: A cowry puzzle - thinking cap req'd...


> Not just for cowry aficionados...
>
> I'd like to share a curiosity I've just encountered
> which concerns one of Hawaii's endemic cowries.
> Perhaps some of our CONCH-Lers have seen something
> like this and/or are willing to share their
> thoughts about possible explanations or causes.
>
> ************
>
> I have a group of ~1350 Grooved-Tooth cowries with
> the following coefficients of correlation to the
> groups' averaged lengths (a method I used before
> in http://www.cowrys.org/research/hlvteeth.htm ):
>
> For ~1350 Cypraea sulcidentata:
> labial teeth correlate to avgd. lengths ------------0.94
> columellar teeth correlate to avgd. lengths --------0.96
> labial minus col. teeth correlate to avgd. lengths--0.24
>
> Then I separated the fresh-dead/live-collected shells
> from the faded, glossless 'beach' shells, making groups
> of ~570 and ~780 shells, respectively. The coefficients
> of correlation for these two are:
>
> labial minus columellar teeth to avgd. lengths:
>     "beach"         "fresh"
>       +0.32           +0.95
>
> That is a surprise! Who would guess that a group with
> such a close link between the difference of tooth counts
> and the averaged lengths of their groups could emerge
> from such a group! Their only difference is the time period
> in which they grew. Just about every one of these shells
> came from Makua. The live-collected shells were taken in
> the last twenty to thirty years, while the 'beach' shells,
> taken from the 'pockets' (ancient sinkholes) of Makua)
> are probably four or more decades old, and some are probably
> hundreds of years old.
>