Description:
Cayenne keyhole limpets are easily identified due to the keyhole-shaped orifice at the apex of the shell.  They typically reach 1 - 2 inches in diameter, and are a white, pink-gray or gray in color.  The shell is etched with many radial ribs, with every fourth rib being larger.  Interior of the shell is white or blue-gray. 

Habitat:
Cayenne keyhole limpets are found from the intertidal zone to depths of approximately 100 feet.  They are generally observed attached to rocks or other hard substrates. 

Similar Species:
There are several limpet species within the Indian River Lagoon that are similar to the cayenne keyhole limpet.  Lister's keyhole limpet (Diodora listeri) is perhaps the most similar.  However, it tends to be more coarsely ribbed, with every second rib larger.  Another similar species is the meta keyhole limpet (Diodora meta).  This species is easily distinguished because its orifice in the shell apex is circular, not keyhole shaped.  It is also significantly smaller, growing only to 1/2 inch in diameter.

Range:  
Cayenne keyhole limpets range from Maryland and Bermuda south through Florida, the Gulf of Mexico, and the Caribbean to Brazil.