Hello Andre:
Some nice photos and specimens.
  Your photo # 1 is Gaza superba superba
  Your photo # 2 is Gaza superba cubana
        … but G. cubana in the sense that it has coloration is the umbilicus.

The member of the Genus Gaza from the Western Atlantic are: (after Clench &
Aguayo, 1943)
  Gaza superba superba Dall, 1881
        Northern Gulf of Mexico, Greater & Lesser Antilles, Columbia,
  Gaza superba cubana Clench & Aguayo, 1943
North coast of Cuba
  Gaza superba olivacea Quinn, 1991
        Honduras to Colombia & Guiana
  Gaza fischeri Dall, 1889
        Northern Cuba to the Lesser Antilles
  Gaza (Callogaza) watsoni Dall, 1881
North coast of Cuba

After much study of W.A. Gaza, it is my forgone conclusion that there are only
2 species in the Western Atlantic:  G. superba & G. watsoni;   with G. Cubana,
fischeri, & olivacea being nothing more than forms or subspecies at best.
There is a tremendous amount of overlap of those varieties.  It is very
reminiscent of 15 years of research I did on Calliostoma bruneum (Dall, 1981)
vs. C. tejedori Clench & Aguayo, 1949; where by it has much the same range and
overlap issues, as well as variability in sculpture and other morphological
details.

Hope this has been helpful.
Leslie

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From: Andre Poremski <[log in to unmask]>
To: [log in to unmask]
Date: Mon, 12 Feb 2007 11:59:07 -0500
Subject: Gaza superba

Dear Conch-Lers

I recently received a nice lot of Gaza superba (labeled G. superba cubana) that
were dredged from the Mississippi delta in the late sixties.
I compared these specimens with one superba that I already had in my collection
that was dredged in the Gulf off Florida's west coast...they were slightly
different.  The new group seemed to lack the iridescence on the spire normally
associated with superba.

Here are the pictures:

Specimen from my collection: http://www.poremski.com/images/study/gaza_1.jpg

Sample specimen from new lot: http://www.poremski.com/images/study/gaza_2.jpg

[Both specimens are roughly the same diameter.]

Is it a periostracum that is causing the difference in appearance?  Is the
difference influenced by locality?  Is there any way to clean the shell further
to bring out the classic Gaza iridescence without ruining the shell?

Thanks in advance for you input.

Kind regards,
Andre Poremski

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