Caribbean Cup-and-Saucer Shell, Bonnet Limpet
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Calyptraeidae, Genus: Crucibulum, Species: C. auricula · Calyptraeidae (Cup-and-saucer shells and Slipper snails) · Gastropod (Snail/Univalve); Limpet-like conical shape
Species
Crucibulum auricula
Shell Type
Gastropod (Snail/Univalve); Limpet-like conical shape
Family
Calyptraeidae (Cup-and-saucer shells and Slipper snails)
Size
Approximately 20-25mm (0.8-1 inch) in diameter. This is a very typical size for an adult specimen of this species.
Color & Pattern
Dull chalky white exterior with a slight yellowish-tan stain. The surface is sun-bleached and worn, lacking the darker brown or purplish rays often found in living specimens. Interior is likely white and glossy.
Rarity
Common; frequently found on Caribbean beaches, though often in worn or beach-rolled condition as seen here.
Habitat
Found in shallow marine intertidal and subtidal zones, typically attached to rocks, other shells, or hard substrates in sandy areas.
Geographic Range
Western Atlantic; specifically from Florida to the West Indies, including the Caribbean Sea (Cancun/Yucatan Peninsula) and Brazil.
Description
A cap-shaped shell with a circular or slightly oval base. The exterior surface is characterized by numerous fine radiating ribs and concentric growth lines. The apex is slightly off-center and twisted. If turned over, this shell contains a small, cup-like internal shelf (the 'cup') which resembles a teacup inside a saucer.
Key Features
Conical 'Chinese Hat' shape; internal cup-like structure (though apex is damaged here); radiating ribs; slightly asymmetrical apex.
Collector Value
Low. This is a common species, and the current specimen is damaged (broken apex) and worn. It holds primarily sentimental or educational value as a beach find.
Condition Notes
Fair condition only. The apex is broken/missing, revealing the internal structure. The shell is heavily beach-rolled (smoothed by sand and surf) and sun-bleached. Grade: Fair/Poor for a scientific collection.
Interesting Facts
These animals are protandric hermaphrodites, meaning they start life as males and may eventually change into females. They are filter feeders that use their gills to strain plankton from the water while remaining stationary.
Ecological Role
Primary consumer/Filter feeder; helps clarify water by filtering organic particles. They serve as prey for crabs and predatory snails like drills.
Similar Species
Crucibulum striatum (found further north) and Calyptraea centralis, which is smoother and lacks the prominent radiating ridges.
Beach Finding Tips
Look in the 'shell hash' lines at low tide after storms in Cancun. Because they are light, they are often pushed to the highest tide line among coral fragments and seaweed.
Notes
Cancun