The heavy shells are tough to get.  I doubt they are actually uncommon, just
not on the market due to location.  The question of consistency is why I
have not written an article as yet.  I have only a single specimen of the
heavy South China Sea type and would like to examine a couple more before
offering up the question as to the status of the two.  The heavy shell is
quite obviously T. martinii - or at least, it is more that species than any
other Tibia species.  It would seem they are at least subspecies as I have
not heard of the heavy form coming from the Philippines where the light form
is common.  It would now be nice to know if anyone has a thin, light T.
martini from north of the Philippines.

Tom Eichhorst in New Mexico (with my new (blisteringly fast) computer that
should be paid off not too long after it is outmoded and out of date).

-----Original Message-----
From: Conchologists List [mailto:[log in to unmask]]On Behalf Of
Andrew Grebneff
Sent: Tuesday, January 04, 2005 12:25 AM
To: [log in to unmask]
Subject: Re: Tibia martinii... Gijs?


>I have specimens from both the Philippines (very thin, the "standard" Tibia
>martinii) and from the South China Sea (very thick and heavy, like T.
>curta).  The two are quite different and I had planned on one day doing an
>article on them.  In the mean time, here are some measurements taken of the
>two shells that highlight just how different they are.
>
>South China Sea (deep water)
>151mm total length
>3mm outer lip thickness
>1.5mm thickness inside lip
>34.5 grams total weight
>No white subsutural band
>Weak purple banding
>Seven outer lip digits
>Moderately deep spiral cording
>Unevenly tapered teleoconch
>
>Philippines (deep water)
>116mm total length
>1mm outer lip thickness
>.05mm thickness inside lip
>7.2 grams total weight
>White subsutural band
>Strong purple banding
>Five outer lip digits
>Shallow spiral cording
>Evenly tapered teleoconch
>
>As you can see, the South China Sea specimen is almost five times as heavy
>as the Philippine shell and has a much thicker shell.  The Philippine shell
>is extremely thin and feels almost like a common garden snail, Helix
aspersa
>(or whatever the most recent name is).  I also have comparison photographs
>if anyone is really interested.
>
>Tom Eichhorst in New Mexico where it is snowing tonight.

This sounds very much as though they were two species. How consistent
are the differences? Comments, Gijs?

How do I go about obtaining one of the heavy shells?
--
Andrew Grebneff
Dunedin
New Zealand
Fossil preparator
<[log in to unmask]>
Seashell, Macintosh, VW/Toyota van nut

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