> I just returned from a diving trip to Palau and while on several WWII
> shipwrecks at 60-100', I came across hundreds of what appeared to be Pteria
> penguin lotorium and Lopha cristagalli that were close to or over 12" in
> length. Does anyone know if these species get this large? I wasn't able to
> photograph or collect these oysters but these are what I believed I saw.


Hyotissa hyotis (Gryphaeidae) is commonly mistaken for Lopha
cristagalli (Ostreidae). It attains at least 30cm in length. It can be
distinguished from L. cristagalli by its semitubular spines (none in
L. cristagalli), smooth surface with coarse growthlines (finely but
strongly malleated) and more numerous plaits. There are differences in
the hinge and muscle scars as well. It seems that H. hyotissa is far
more common.

--
Regards
Andrew Grebneff
Dunedin
New Zealand
Fossil preparator
Mollusc, Toyota & VW van fan

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