Atlantic Wing Oyster (also known as the Winged Oyster)
Phylum: Mollusca, Class: Bivalvia, Order: Ostreida, Family: Pteriidae, Genus: Pteria, Species: Pteria colymbus · Pteriidae (Winged Oyster family) · Bivalve (fragment of one valve). Classically fan-shaped/oblique with a wing-like extension, though this specimen is heavily eroded.
Species
Pteria colymbus (Confidence Level: 85% based on ribbing and locality)
Shell Type
Bivalve (fragment of one valve). Classically fan-shaped/oblique with a wing-like extension, though this specimen is heavily eroded.
Family
Pteriidae (Winged Oyster family)
Size
Approximately 1.5 - 2 inches. This is small-to-average; adults can reach 3-4 inches. The fragment suggests a medium-sized individual.
Color & Pattern
Faded purplish-brown base with cream or white radial banding. The interior nacre (mother-of-pearl) is not visible due to the angle and erosion. The colors appear sun-bleached and worn by surf action.
Rarity
Common (as beach-worn fragments), though intact live-collected specimens are more elusive.
Habitat
Marine. Typically found in shallow subtidal waters attached by a byssus to gorgonians (sea whips and sea fans) or other hard substrates.
Geographic Range
Western Atlantic, ranging from North Carolina south to Brazil, including the Gulf of Mexico and the Caribbean.
Description
This is a beach-worn fragment of an Atlantic Wing Oyster. It shows the characteristic oblique shape and prominent, slightly scaly radial ribs. The shell is naturally thin and somewhat brittle, which causes it to break easily in the surf. This specimen exhibits significant weathering, revealing the internal calcite layers.
Key Features
Distinguished by the diagonal orientation of the growth lines relative to the hinge, prominent raised radial ribs, and the distinct purplish-brown and white striped pattern common to Pteriidae in the Atlantic.
Collector Value
Minimal. While the species is attractive when whole and fresh, beach-worn fragments like this have almost no monetary value. Intact collector specimens with the 'wing' attached are much more desirable ($2-$10).
Condition Notes
Poor to Fair. This is a heavily eroded fragment with missing margins and clear signs of bioerosion (small holes likely from Cliona sponges). It lacks the 'wing' and the delicate hinge characteristic of a whole shell. Collectibility Grade: Poor (Beach find/Study grade).
Interesting Facts
The Atlantic Wing Oyster almost exclusively attaches itself to sea whips (Leptogorgia virgulata). Because they grow on these flexible corals, the oysters are often found washed up after storms that dislodge the host colony. They are capable of producing small, low-quality pearls.
Ecological Role
They are filter feeders that help clear the water column of plankton. By attaching to sea whips, they create a micro-habitat for other small marine organisms. They are not currently considered threatened, though their habitat (gorgonians) can be sensitive to pollution.
Similar Species
Pinctada imbricata (Atlantic Pearl Oyster), which is rounder and less oblique; and various species of Mytilidae (mussels), which typically lack the prominent raised radial ribbing seen here.
Beach Finding Tips
In Myrtle Beach, look for 'wrack lines' containing washed-up sea whips after a storm. The best time to find intact wing oysters is at low tide following a period of high onshore winds.
Notes
Myrtle Beach SC