Rough Scallop (also known as the Atlantic Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Aequipecten, Species: Aequipecten muscosus · Pectinidae (Scallop family) · Bivalve (single valve present); Fan-shaped with distinct wings (auricles).
Species
Aequipecten muscosus
Shell Type
Bivalve (single valve present); Fan-shaped with distinct wings (auricles).
Family
Pectinidae (Scallop family)
Size
Approximately 1 inch (2.5 cm). This is a juvenile or smaller specimen; adults typically reach 1.5 to 2.5 inches.
Color & Pattern
Striking bicolor pattern with a bright orange distal half and a white/cream proximal half near the umbo. This specimen shows natural pigmentation with clear, sharp radial ribs. The interior is likely white or tinted with the exterior orange.
Rarity
Common. While the species is common, specimens with such vivid orange-and-white contrast are highly desirable for casual beachcombers.
Habitat
Intertidal to deep water (up to 300 feet). They prefer sandy or coral rubble bottoms, often near seagrass beds in marine environments.
Geographic Range
Western Atlantic from North Carolina to Brazil, including the Gulf of Mexico and the Caribbean Sea.
Description
A beautiful fan-shaped bivalve with roughly 18-22 strong radial ribs. The ribs are decorated with small, scale-like spines (erect scales) that give the shell a 'rough' texture. The 'ears' or auricles at the hinge are unequal in size, a classic scallop trait.
Key Features
Strong radial ribs with small protruding scales/spines; unequal auricles (ears); vivid orange coloration; circular fan-shape profile.
Collector Value
Low monetary value ($1-$5) but high aesthetic value for 'color' collectors. Vividly colored specimens like this are often kept as reference pieces for North American Atlantic collections.
Condition Notes
Fine to Good condition. The shell appears mostly intact, though the smaller wing (auricle) shows some slight wear. The color is exceptionally vibrant, suggesting it hasn't been sun-bleached for long. No evidence of boring sponge or predator holes.
Interesting Facts
Unlike many bivalves, scallops have a row of dozens of small, bright blue eyes along the edge of their mantle that can detect movement and light. They can also 'swim' by rapidly snapping their valves together to create jet propulsion.
Ecological Role
Filter feeders that help improve water clarity by consuming plankton and organic detritus. They serve as a vital food source for sea stars, octopuses, and various crustacean species.
Similar Species
Caribachlamys sentis (Sentis Scallop) which has more numerous, finer ribs, and Argopecten irradians (Bay Scallop) which lacks the small sharp scales on the ribs.
Beach Finding Tips
Look for these in the 'shell hash' line after a storm or a strong high tide. They are often found attached to sea whip corals or hidden in seagrass that has washed ashore. Best found on Florida Gulf Coast and Caribbean beaches.