Pecten / Scallop shell
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Argopecten, Species: Argopecten irradians · Pectinidae (Scallop family) · Bivalve (two-shelled), whole shell, fan-shaped
Species
Argopecten irradians
Shell Type
Bivalve (two-shelled), whole shell, fan-shaped
Family
Pectinidae (Scallop family)
Size
Approximately 1.5 to 2 inches in width and height, which is typical for an adult bay scallop.
Color & Pattern
Mottled and patterned with brownish-red spots and zig-zag markings over a cream or off-white background, featuring distinct concentric growth lines and radiating ribs.
Rarity
Common, frequently found washed ashore on beaches within its geographic range.
Habitat
Shallow marine waters, typically found in seagrass beds, eelgrass meadows, and sandy or muddy substrates in bays and estuaries.
Geographic Range
Coastal Atlantic waters of North America, ranging from Nova Scotia down to the Gulf of Mexico and the Caribbean.
Description
A charming and compact bivalve shell featuring a classic fan shape with pronounced radial ribs and distinct concentric growth stages. The exterior showcases attractive brownish-red patterning on a light background, and the margins are scalloped to match the internal ribbing structure.
Key Features
Symmetrical fan-like shape, prominent radiating ribs, distinct concentric growth rings, and a pair of unequal auricles (ears) at the hinge line.
Collector Value
Low to moderate value as a common beach find, though exceptionally large, brightly colored, or pristine specimens are popular in decorative crafts and beginner collections.
Condition Notes
Good overall condition with natural coloration intact, minor wear around the margins typical of a beach-collected specimen. Grade: Good.
Interesting Facts
Scallops are unique among bivalves because they can swim by rapidly snapping their shells together to expel water, and they possess dozens of simple blue eyes along the mantle edge that can detect light and shadow.
Ecological Role
Bay scallops serve as active filter feeders that help maintain water clarity and act as an important food source for various marine predators, fish, and birds.
Similar Species
Atlantic Calico Scallop (Argopecten gibbus), which tends to be more convex and heavily mottled with brighter colors, and the Sea Scallop (Placopecten magellanicus), which is much larger and flatter.
Beach Finding Tips
Search the high tide line on sandy ocean beaches or bay shores, particularly after storms or during low tide in areas near seagrass flats.