Rays and sharks are closely related. They are both cartilaginous fish, meaning they have cartilage for skeletons rather than bones. Sharks and rays both have gill slits or clefts and don’t have a swim bladder. They both have dermal denticles which are modified “scales” covering their skin referred to as shagreen. They also have ampullae of Lorenzini sensory organs called electroreceptors in common too.