Mollusca · mollusks

Atlantic surfclam

Spisula solidissima

Mactridae · surf clamsIUCN: Not evaluated
Atlantic surfclam
Photo: Invertzoo · CC BY 3.0 · Wikimedia Commons · resized

The largest bivalve on the US Atlantic coast, used for clam strips and chowder.

Fun factWarming waters have pushed its range deeper and farther north.

Waters
Northeast US, Northwest Atlantic
Depth zone
Coastal shallows & estuaries, Continental shelf
Diet
Plankton (filter feeder)
Size
Shell up to 22 cm

Classification

Mollusca › Bivalvia › Mactridae

  1. Kingdom Animalia animals
    • Many-celled organisms that eat other living things for energy (heterotrophs)
    • Cells have no cell walls
    • Most can move at some stage of life
  2. Clade Bilateria bilateral animals
    • Body has a left and right side that mirror each other (bilateral symmetry)
    • Head end with concentrated nerves; three tissue layers
    • Includes about 99% of all living animal species
  3. Clade Protostomia protostomes
    • In the embryo, the first opening usually becomes the mouth
    • Main nerve cord runs along the belly (ventral)
    • Includes mollusks, worms, and arthropods
  4. Clade Spiralia mollusks, worms & kin
    • Embryos usually divide in a spiral pattern (spiral cleavage)
    • Many have a swimming larva with a band of cilia (trochophore)
    • Includes mollusks and segmented worms
  5. Phylum Mollusca mollusks
    • Soft body with a muscular foot and a fold of tissue (mantle) that makes the shell
    • Most have a rasping, tongue-like ribbon of teeth (radula)
    • Includes snails, clams, octopuses, and chitons
  6. Class Bivalvia clams, oysters & kin
    • Body enclosed in two hinged shells (valves)
    • No head and no radula
    • Most filter food from water with large gills
  7. Subclass Heterodonta clams & cockles
    • Hinge has distinct cardinal and lateral teeth
    • Many burrow in sediment using a long siphon
    • Includes clams and cockles
  8. Family Mactridae surf clams
    • Surf clams: thick, triangular-oval shells
    • Burrow in sandy beaches and shelf bottoms
  9. Genus Spisula
    • Species in the same genus are very close relatives and often look alike.
  10. Species Spisula solidissima Atlantic surfclam

Closest relatives in the guide