I agree its an oyster. Perhaps a pearl oyster Pinctada sp.?

Dear Soroor,

This is closest to the young specimen of giant coxcomb oyster Hyotissa hyotis (Linnaeus, 1758) - Gryphaeidae. But I am not sure if it is reported from the Persian Gulf! 

http://www.conchology.be/images/Label/760000sup/767885.jpg

Best regards

Deepak

It Looks like Honey Comb Oyster,Hyotissa hyotis 

Hi! Soroor,

I agree with Drs. Deepak and Sethi. Yes this is known Hyotissa hyotis and it is recorded from Persian Gulf. Please refer to :

Bosch, T., Dance, S.P., Moolenbeek, R.G. and Oliver , P.G. Sea shells of Eastern Arabia. Ed. Dance P.S. Motivate Publishing. p. 229. 

Best Regards,

M. Nithyanandan

Thanks for the information Dr Nithy! 

I agree with Drs Deepak, Sethi and Manickam it is a Hyotissa hyotis from the Persian Gulf, look on:

thanks a lot

but Dr, Ardinovi, the version of this book that i have is old and the pictures are not very clear, so its difficult to me identify from this book.

thanks for your response

with best regards

Your specimen looks most like Spondylus sp.  (possibly S. regius)   .  Scallops in this genus attach to rock or other hard surfaces.

Definitely an oyster and not a spondylid (very different hinge). Hyotissa is a good guess, but can't even tell the family without a close-up of the hinge region. Hyotissa has vermicular chomata (wavy lines) adjacent to the hinge. Good luck!

thanks a lot for your response

Best regards