The common slipper shell, Crepidula fornicata, has many other common names including common Atlantic slippersnail, boat shell, quarterdeck shell, and it is known in Britain as the "common slipper limpet". This is a species of medium-sized sea snail, a marine gastropod mollusc in the family Calyptraeidae, the slipper snails and cup and saucer snails.
The species is native to the western Atlantic Ocean
, specifically the Eastern coast of North America
. It has been introduced accidentally to other parts of the world and has become problematic.
As an invasive species
The species is considered an invasive species
, the Netherlands
, and the UK
, and has also spread to Norway
. It is known to damage oyster
fisheries. It has also been introduced to the Pacific Northwest
This is a common snail, found intertidally
to a depth of 40 ft
They are often found, sometimes living stacked on top of one another, on horseshoe crabs, rocks, shells and on dock pilings.
It has an arched, rounded shell. On the inside of the shell there is a white "deck" which causes the shell to loosely resemble a boat or a slipper, hence the common names.
The species is a sequential hermaphrodite
. The largest and oldest animals, at the base of a pile are female
, the younger and smaller animals at the top are male
. If the females in the stack die, the largest of the males will become a female.