SeaShell News, 3-4-15, Dwarf Zigzag Scallop, Shelling, Captiva Island.
“Euvola ziczac, or the zigzag scallop, is a species of bivalve mollusc in the family Pectinidae. It can be found along the Atlantic coast of North America, ranging from North Carolina to the West Indies and Bermuda.
Euvola ziczac is known by many names. Previously, its scientific name was Pecten ziczac, but most current literature lists both Euvola and Pecten for clarity. Like other scallops, zigzag scallops bear the characteristic two-valved, calcium carbonate shells that are rounded along the outer edges and flattened at the bottom near the prominent hinges. On either side of the hinge are projecting “ears” or auricles that contribute to scallops’ distinctive shapes. In Bermuda, zigzag scallops commonly grow to 120 mm, but they are generally not as large in the Caribbean.
Zigzag scallop shells show a wavy, crenulated pattern along their outer edges and have several colored rays varying from white to orange, yellow, or gray. Within this pattern are well-defined annual rings which make determining a scallop’s age relatively easy to the trained eye. The zigzag scallop’s lower valve is somewhat cup-shaped, whereas its upper valve forms a flat to concave lid. They exhibit a zigzag pattern of stripes on their shells which gives the species its name. Interestingly, it also moves in a zigzag pattern when jetting.
Zigzag scallops in particular have a series of bright blue eyes along the edge of their mantles. These eyes, ocelli, are sensitive to changes in light intensity, and signal the animals to close their shells if they sense a change in shadows or another nearby disturbance. The scallops also close their shells if exposed to the air or mildly threatened. Surrounding the ocelli are small sensory tentacles which line the conspicuous inner fold of the mantle. These serve to regulate water flow into and out of the animal.”
Source: Zigzag Scallop.