Atlantic Surf Clam, or Hen Clam
Phylum: Mollusca, Class: Bivalvia, Order: Adapedonta, Family: Mactridae, Genus: Spisula, Species: Spisula solidissima · Mactridae (Surf Clams or Trough Shells) · Bivalve (clams); specimen is a single valve (right valve) with an oval-triangular shape.
Species
Spisula solidissima
Shell Type
Bivalve (clams); specimen is a single valve (right valve) with an oval-triangular shape.
Family
Mactridae (Surf Clams or Trough Shells)
Size
Approximately 2.5 to 3 inches in length. This is a juvenile or sub-adult specimen, as mature adults can reach 7 to 8 inches.
Color & Pattern
Creamy white to light tan base. Features concentric growth rings in shades of grayish-brown. The exterior shows some beach-worn dullness, lacking the yellowish-brown periostracum typical of live specimens.
Rarity
Very Common; one of the most frequently found shells on Northern Atlantic beaches after storms.
Habitat
Marine; primarily found in the surf zone of sandy beaches and subtidal waters down to about 100 feet deep. They live buried just beneath the sand surface.
Geographic Range
Western Atlantic, ranging from Nova Scotia, Canada, to Cape Hatteras, North Carolina.
Description
A sturdy, thick-walled bivalve with a smooth, somewhat glossy exterior. The shell is roughly triangular with rounded edges. The umbo (beak) is central and prominent. It features fine concentric growth lines and a large, spoon-shaped chondrophore (internal hinge pit) on the interior.
Key Features
Distinguished by its smooth surface, triangular-oval shape, and the prominent internal spoon-shaped pit in the hinge area for the ligament.
Collector Value
Minimal financial value (typically $1-$5 for exceptional large specimens) due to its abundance. It is mostly valued by beginner collectors and for craft use.
Condition Notes
Fair to Good condition. The shell is intact with no major chips, but it shows signs of beach weathering (loss of periostracum and slight softening of surface detail). Collectibility grade: Good.
Interesting Facts
This species is the primary source of 'clam strips' in the United States. They have a massive foot that allows them to burrow rapidly into the sand to escape predators and shifting waves.
Ecological Role
Important filter feeders that help clarify seawater. They are a vital food source for sea stars, moon snails, gulls, and various fish species. They are also a significant commercial fishery resource.
Similar Species
Mactromeris polynyma (Arctic Surf Clam) which is usually smaller and found in colder waters, and Mulinia lateralis (Little Surf Clam) which is much smaller, usually under an inch.
Beach Finding Tips
Look along the high-tide line after a heavy storm or strong onshore winds. They are most abundant on expansive, sandy Atlantic beaches.