Mabye ask Dr. Sabine Stohr at the Naturhistoriska Riksmuseet i Sweden, Stockholm. She's an expert on this echinoderm class, and has been working with Collections from all around the world.
Dear Soroor, your specimen is a member of the family Ophiactidae (Ophiactis sp.). As Halldis told you, I recommend to contact Dr. Sabine. Kind Regards.