Skip to Main Content

Central and South Florida Gastropod Seashell Identification Guide: True Limpets, Keyhole Limpets, and Slipper Snails

This guide should serve to teach the public how to identify local Central and South Florida gastropod seashells.
Eoacmaea pustulata

Spotted Limpet

Diodora cayenensis

Cayenne Keyhole Limpet

Crepidula fornicata

Common Atlantic Slipper Snail

Crepidula maculosa

Spotted Slipper Snail

Bostrycapulus aculeatus

Spiny Slipper Snail

True Limpets

(Order) Patellogastropoda

Distinguishing Characteristics: The True Limpets have a simple flattened conical shell without whorls or spire. 

Habitat:  These snails prefer intertidal rocky shores.

Diet:  This order grazes on algae that grows on rocks.

Scientific Name:  Eoacmaea pustulata

Common Name:  Spotted Limpet

Distinguishing Characteristics:  Thick shell with coarse ribs, crisscrossed to form a netlike top.  Shell is flecked with red dots, which give the species its common name.  Maximum size 1 inch.

Keyhole Limpets

(Family) Fissurellidae

Distinguishing Characteristics: The Keyhole Limpets have a simple flattened conical shell without whorls or spire.  There is a hole at the top of the shell which gives the family its common name.

Habitat:  These snails prefer to live on hard bottoms and in seagrass beds in intertidal waters.

Diet:  This family grazes on algae that grows on rocks.

Interesting Facts:  The hole at the top of the shell is actually the keyhole limpet's anus.

Scientific Name:  Diodora cayenensis

Common Name:  Cayenne Keyhole Limpet

Distinguishing Characteristics:  The keyhole is off-center when viewed from above. There is a raised callous around the keyhole on the interior of the shell.  Shell is covered with irregular rib-like ridges.  Maximum size 1.5 inches.

Slipper Snails

(Family) Calyptraeidae

Distinguishing Characteristics: The Slipper Snails have a shell resembling that of a clam, but with no bottom half of a shell like a bivalve.  There is no spire.  The underside of the shell has a distinctive shelf-like platform sometimes called a "septum".  The shelf makes the underside resemble a slipper, giving the family its name.

Habitat:  These snails prefer to live on rocky bottoms.  They may often be found inside of other shells.

Diet:  This family are suspension feeders that feed upon plankton in the water column.

Interesting Facts:  Slipper snails can often be found settling on top of each other, forming small towers of snails.

Scientific Name:  Crepidula fornicata

Common Name:  Common Atlantic Slipper Shell

Distinguishing Characteristics:  Shell a long oval with a very large interior shelf.  Shell is asymmetrical, with the top of the shell curving to a side.  Shell is cream with brown or tan speckles and long uninterrupted brown lines.  Maximum size 1.5 inches.

Interesting Facts:  Common names include Common Atlantic Slippersnail, Boat Shell, Quarterdeck Shell, Fornicating Slipper Snail, Atlantic Slipper Limpet, Oysterpest, American Slipper-Limpet, and the Common Slipper Limpet.

Scientific Name:  Crepidula maculosa

Common Name:  Spotted Slipper Snail

Distinguishing Characteristics:  Shell cream to gray, spotted with reddish brown. Muscle scars visible under the right edge of the shelf.   Top of the shell centered.  Maximum size around 1.5 inches.

Scientific Name: Bostrycapulus aculeatus

Common Name:  Spiny Slipper Shell

Distinguishing Characteristics:  Heavily sculptured reddish-orange shell, covered with spines in spiralling rows.  The shell is asymmetrical, with the top of the shell curving to a side.  Maximum size 1 inch.