Soroor:

Kindly examine both interior view for size, position and shape of muscle scar and hinge and exterior of the valve for ornamentation.  This link might prove helpful:

http://nopr.niscair.res.in/bitstream/123456789/4307/1/IJMS%2031(2)%20108-118.pdf

Best

Syed

This is a Striostrea maragaritacea (Lamarck. 1819) common in Persian Gulf.

The Spondylus that you send on my mail address resembling an ugly gaderopus of Mediterranean sea but you take in Persian Gulf and so it could be only Spondylus marisrubri Roeding, 1798. 

thank a lot Dr.Ardovini

do you have a reference for Striostrea maragaritacea? i can not find it i will tank you if you send me a picture of it in a article or a book.

by the way, its not Saccostra cucullata?

and about spondylus sp 1, the triangular projection in my species is smaller than S. marisrubri, its not problem?

and about spondylus sp 2, you don't have any opinion?

thanks  a lot

with best regards