Mollusca · mollusks

Atlantic slipper snail

Crepidula fornicata

Calyptraeidae · slipper snailsIUCN: Not evaluated
Atlantic slipper snail
Photo: H. Zell · CC BY-SA 3.0 · Wikimedia Commons · resized

A slipper-shaped snail that lives in stacks of up to a dozen individuals.

Fun factIt changes sex from male to female as it grows, and the stack's bottom snail is the largest female.

Waters
Northeast US, Northwest Atlantic
Depth zone
Coastal shallows & estuaries
Diet
Plankton (filter feeder)
Size
Shell up to 5 cm

Classification

Mollusca › Gastropoda › Littorinimorpha › Calyptraeidae

  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 Gastropoda snails & slugs
    • Snails and slugs, most with a single, often coiled shell
    • Body twists 180 degrees during development (torsion)
    • Crawl on a broad muscular foot
  7. Subclass Caenogastropoda whelks, periwinkles & kin
    • Most have a single gill and a shell door (operculum)
    • Many have a siphon to sample water
    • Includes periwinkles, whelks, and conchs
  8. Order Littorinimorpha periwinkles, conchs & kin
    • Large, varied group including periwinkles, conchs, and moon snails
    • Many graze algae; some drill or filter-feed
  9. Family Calyptraeidae slipper snails
    • Slipper and cup snails with a shelf inside the shell
    • Filter-feeders that often live stacked on each other
  10. Genus Crepidula
    • Species in the same genus are very close relatives and often look alike.
  11. Species Crepidula fornicata Atlantic slipper snail

Closest relatives in the guide