Atlantic Kitten's Paw (also known as Kitten's Paw or Kitten's Paw Bivalve)
Kingdom: Animalia > Phylum: Mollusca > Class: Bivalvia > Order: Ostreida > Family: Plicatulidae > Genus: Plicatula > Species: Plicatula gibbosa · Plicatulidae (Kitten's Paw or Cat's Paw family) · Bivalve (single valve shown, upper valve). Fan/triangular shape with thick, rounded radial ribs.
Species
Plicatula gibbosa
Shell Type
Bivalve (single valve shown, upper valve). Fan/triangular shape with thick, rounded radial ribs.
Family
Plicatulidae (Kitten's Paw or Cat's Paw family)
Size
Approximately 0.5 inches (12-15 mm) in height, resting on an adult palm. Typical range for full adults is 0.5 to 1 inch (12 to 25 mm).
Color & Pattern
Muted tan and grayish-white base with strong reddish-brown to dark chestnut bands and stripes running along the prominent radial ribs. The interior (not visible) is typically white with brownish margins.
Rarity
Common to Very Common on southeastern US beaches, especially along the Florida coast (e.g., Sanibel Island).
Habitat
Subtidal marine environments from shallow water down to about 60 meters depth. Prefers hard substrates, gravel, sand, shell debris, or reef structures where it cement-attaches by its lower valve.
Geographic Range
Western Atlantic: North Carolina south to Florida, the Gulf of Mexico, the Caribbean Sea, and south to Brazil.
Description
A small, thick, heavy bivalve valve resembling a tiny cat or kitten paw. Features 5 to 9 strong, rounded radial ribs that end in wavy, scalloped margins. The surface shows fine growth lines crossing over the ribs.
Key Features
Distinct paw-like appearance created by 5-7 heavy, radiating plications (ribs); thick and heavy shell structure relative to its tiny size; distinctive reddish-brown to reddish-orange striping on the ribs.
Collector Value
Low monetary value ($0.50 - $2.00) due to abundance, but highly popular among beachcombers and crafters for its charming, recognizable shape.
Condition Notes
Fair to Good. Beach-worn condition with moderate surface erosion and loss of sharp sculpture detail near the umbo. Colors remain clear on the ribs. Grade: Good.
Interesting Facts
Kitten's Paws attach themselves permanently to rocks or larger shells by cementing their right (lower) valve, much like oysters. The valve seen on beaches is almost always the upper (left) valve that detaches after death.
Ecological Role
Filter feeder that consumes plankton and organic detritus from the water column, helping clarify coastal waters. Serves as prey for crabs, predatory snails, and sea stars.
Similar Species
Spondylus species (Thorny Oysters) which have spiky ornamentation, and small Pecten/Scallop species which have distinct symmetrical ears (auricles) at the hinge line.
Beach Finding Tips
Look along the high-tide line and in shell drift lines on Florida and Gulf coast beaches after high winds or stormy weather.