Shell of the Week: The Angel Wing
Cyrtopleura costata (Linnaeus, 1758) is one of the local iconic species, forming, with the Lion Paw, Junonia, Scotch Bonnet, and Alphabet Cone, a “quintet of desirables” for collectors of Southwest Florida shells. Depending on the species, members of the family Pholadidae can burrow on rocks, woods, clay, mudstone, and other hard substrates, forming long cylindrical burrows. Angel Wings burrows in compacted mud and can reach about 180 mm (7 inches) in length. Their long siphons cannot be withdrawn inside the shell, and the valves are permanently separated, although joined by the animal’s tissues. A little shelly piece known as mesoplax helps with the rocking movements during burrowing. The shell in the images was collected by Dale V. Stingley in April 1948, on Captiva.