By MARY GRIZZARD
Special to the PRESS
Mermaid’s Toenails. Golden Shells. Saddle Oysters. These are all every day names for the mollusk Anomia Simplex, but it’s best known as the Common Jingle, a small and often overlooked bivalve shell found on South Padre Island beaches. They are extremely thin and translucent, measuring between 1-3”, and they easily blend in with the host of broken shells found at the high tide line. But once the eye is trained to look for them, they are easy to find, and on a clear day they shimmer in the sunlight.
It’s hard to imagine what kind of mollusk could live inside such a thin, flat shell. Jingles are bivalves, like clams, cockles and scallops, and it’s almost always the top portion of the shell that we find on the beach. The reason for this is that unlike most bivalves that move freely about the sea floor or in the water column, once jingles mature they attach themselves to a hard substrate, such as pier pylons, rocks, oyster beds and other seas shells. The lower shell of the jingel is cemented to the structure to which it has attached itself, and when the organism dies the lower shell typically remains afixxed while the upper shell breaks away and drifts in the current.
Jingles, like most bivalves, begin their life cycle as eggs which hatch into veligers (minute, free swimming larvae) that are part of the ocean’s zooplankton community. Once they near maturity they drop to the shallow ocean floor and, by means of an appendage called the foot, drag themselves along until they find a suitable substrate for attachment. The jingle then uses byssus threads produced by the lower valve, or shell, and these protrude through a hole to bind the lower shell to the substrate. These threads then calcify, permanently cementing the jingle in place.
Jingles are found not only in the Gulf, but along the entire Atlantic coast as far as Brazil. They rarely live in water more than 30 feet deep. They are filter feeders, waiting for waves and currents to bring planktonic organisms which are then entrapped in their gills and consumed.
Humans report that the meat of a Common Jingle is very bitter, although shorebirds, fish, sea stars, and other mollusks seem to find them tasty enough. What humans do use Jingles for is creating artful lampshades, chimes, and jewelry. Despite the shell being thin, they are relatively strong and work well for these craft items.
Last but not least — why are they called Jingles? This name comes from the tinkling sound they make when several shells are placed together in a bag, like coins in an old-fashioned drawstring purse. Perhaps a South Padre Island Santa will use Jingles on his reindeer harness this Christmas Eve!