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Prickly cockles are a distinctive, easily identified species.  They grow to approximately 3 inches, with the somewhat elongate shell reaching 2 inches in height.  The shell has 27 - 31 radial ribs, each with many raised scales covering the surface.  Color is variable, ranging from white to gray, with patches of yellow, purple, brown, or brick red.  Shell interior is generally glossy with bright hues of salmon, purple or red. 

Prickly cockles are a common shallow subtidal species. They are much more common on the west coast of Florida than on the east coast, though they can be fairly common around inlet areas of the Indian River Lagoon. 

Similar Species:
Prickly cockles may be confused with Trachycardium muricatum, the yellow cockle.  The two are distinguished in that yellow cockles are generally more oval in shape and have 30 - 40  radial ribs.  These ribs are only moderately scaled, and are somewhat smooth at the center of the shell. Further, the interiors of yellow cockle shells may range in color from white to bright yellow.

Prickly cockles are found from North Carolina south through Florida and the West Indies.  They are common in shallow water areas of the Indian River Lagoon, especially around inlets. 

The prickly cockle, Trachycardium egmontianum, from the Indian River Lagoon. Photo courtesy of K. Hill, Smithsonian Marine Station.