Mollusca · mollusks

Hard clam

Mercenaria mercenaria

Veneridae · venus clamsIUCN: Not evaluated
Hard clam
Photo: Ken Hammond · Public domain · Wikimedia Commons · resized

Also called the quahog. It is sold as littlenecks, cherrystones, and chowders depending on size.

Fun factNative peoples carved wampum beads from its purple shell.

Waters
Northeast US, Northwest Atlantic
Depth zone
Coastal shallows & estuaries
Diet
Plankton (filter feeder)
Size
Shell up to 13 cm

Classification

Mollusca › Bivalvia › Veneridae

  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 Veneridae venus clams
    • Venus clams: thick, rounded shells
    • Includes quahogs and other commercial clams
  9. Genus Mercenaria
    • Species in the same genus are very close relatives and often look alike.
  10. Species Mercenaria mercenaria Hard clam

Closest relatives in the guide