Date: Fri, 24 Mar 2006 11:25:40 +0100
Reply-To: Conchologists List <CONCH-L@LISTSERV.UGA.EDU>
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From: Olivier Caro <idscaro@NUMERICABLE.FR>
Subject: A last ostrea! I've shame
Terribly sorry not to have succeeded, here again, to find the answer by myself, but I suppose it's normal that unidentified shells pile up all together at the end of an ID work. Thus, this week, it rains oysters.
The species, the last one (actually) to resist, has no data (if not, it would be too easy, I suppose ?), and is not pictured in my poor 40-50 useful books. But it is possible that these shells were beach collected, 30 years ago.
Quite close to the description made by Olsson of "Ostrea (unplaced) iridescens" (Molluscs of the tropical eastern Pacific / Pelecypoda, Ithaca N.Y 1961 p.174), but not close enough to give me a certainty: irregular shape, attachment area large (they seem able to fix themshelves on everything), wide hinge, "dorsal lateral margins denticulate" (Olsson), and "near the hinge [...] large denticles that fit into sockets in the other valve" (Keen)... But no metallic luster in the interior (Olsson says this metallic layer is fragile, and when removed, lets appear the white porcellaneous background). Lower valve white with foliations, upper valve dark purple, smaller than lower, and of any shape. Interior of both valves mainly white whith shades of [purple, sometimes brown]. Also, the dorsal margins are purple.
Here is the beast. And a pic: http://www.idscaro.net/sci/0.jpg
The eternal Olivier Caro (Question Boy?)