Antillean Scallop (also known as the Spear Scallop)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Bractechlamys, Species: B. antillarum · Pectinidae (Scallop family) · Bivalve (Two-shelled); this specimen is a single valve (either left or right) with a fan-shaped silhouette.
Species
Bractechlamys antillarum
Shell Type
Bivalve (Two-shelled); this specimen is a single valve (either left or right) with a fan-shaped silhouette.
Family
Pectinidae (Scallop family)
Size
Approximately 15-18mm (0.6-0.7 inches). This is a juvenile or smaller-than-average specimen; adults typically reach 20-30mm.
Color & Pattern
Translucent white base with mottled orange-brown and tan patches. The pattern appears as concentric or staggered splashes of pigment across the ribs. The color is natural and relatively unfaded.
Rarity
Common; frequently found as beach wash in the Caribbean, though perfect pairs (both valves joined) are less common on the shore.
Habitat
Shallow tropical waters, typically found in seagrass beds (Thalassia), coral rubble, and sandy bottoms. Found at depths from 1 to 50 meters.
Geographic Range
Western Atlantic; ranging from South Florida and the Bahamas through the Caribbean Sea (including Cancun/Mexico) to Brazil.
Description
A small, delicate, fan-shaped scallop valve. It features roughly 10 to 15 prominent radial ribs that are somewhat rounded. The 'ears' (auricles) at the hinge are unequal in size, a characteristic of many Pectinidae. The texture is finely sculpted with growth lines crossing the ribs.
Key Features
Unequal auricles (ears) at the hinge; approximately 10-15 strong radial ribs; distinctive mottled or 'calico' spotting; relatively small adult size compared to other Caribbean scallops.
Collector Value
Low; while beautiful, this is a common species. It is valued by amateur collectors for its variety of color patterns. Value: $0.50-$2.00 for a single valve; pairs may fetch slightly more.
Condition Notes
Good condition. The valve is intact with no major chips. The color is vibrant, suggesting it was not exposed to the sun for long. Grade: Fine (standard for beach-collected specimens).
Interesting Facts
Scallops are unique among bivalves because they can swim by rapidly snapping their valves together to create jet propulsion. They also possess dozens of tiny, bright blue eyes along the edge of their mantle that detect movement and light.
Ecological Role
Filter feeder that consumes plankton and organic detritus, helping to clarify the water. They are a food source for starfish, crabs, and various predatory gastropods.
Similar Species
Zigzag Scallop (Euvola ziczac) which has one flat valve; Calico Scallop (Argopecten gibbus) which is generally larger and more inflated.
Beach Finding Tips
In Cancun, look along the drift line (the line of seaweed and debris left by high tide). These small shells often get trapped in clumps of sargassum or nestled in the fine white sand near the water's edge.
Notes
Cancun