The shell of Arca zebra is boldly striped in brown and white which gives it a resemblance to the wing of a wild turkey. The whole shell (when both valves are together) has also been likened to Noah's Ark. It is a sturdy shell growing up to 4 in (10 cm) long and 2 in wide. The umbones are separated by a shallow depression, and the hinge is long and straight with about 50 small teeth. There is coarse sculpturing fanning out from the umbones. The inside of the shell is whitish or pale mauve.
This species is found along the Atlantic coast of North America, ranging from North Carolina to the West Indies and Bermuda. It attaches itself to rocks or other hard substrates in shallow water with byssus threads.
Arca zebra is a filter feeder, taking in surrounding water and particulates through its reduced siphons and expelling water while consuming microscopic algae, diatoms, and phytoplankton.
Arca zebra is a protandric hermaphrodite, a type of sequential hermaphrodite with individuals starting out as males and developing female reproductive capacity later in the life cycle. Reproduction is dependent on food availability and seasonal changes. The gonad tissues of Arca zebra change in mass throughout the year. The percentage of somatic tissue mass composed of gonad tissue mass sees a large increase from roughly 4% to 40% from May through late September and a large decrease from roughly 40% to 3% from October through January. The percentage then increases slightly from about 3% to 12% in February before decreasing to around 4% between March and April. Highest reproductive activity occurs around July through late September, when the gonad mass is at its greatest.
Gonad development begins when the shells of Arca zebra are at 18-20mm, and full sexual maturity is reached when the shells are 50-55mm. Larger individuals have greater reproductive output.
Arca zebra has two reproductive periods, one from June to July and the other in September. During each spawn, females can spawn up to four million eggs. Trochophore larvae, a type of planktonic larvae, begin to develop twelve hours after the eggs are fertilized. Six days after fertilization, the larvae begin to take on their adult shape. Eyespots develop seven days after fertilization, with the foot developing soon after. Around the same time the foot develops, food-seeking behavior in the substratum, the sediment at the bottom of the ocean floor, can be observed. Twelve days after fertilization, the larvae begin to settle; about 45% of the larvae reach this stage. Once the larvae reach adulthood, growth mainly happens in the summer, with growth in the summer happening about three times as quickly as in the winter.
