Sea Biscuit, Sand Dollar, Sand Meal
Phylum: Echinodermata, Class: Echinoidea, Order: Clypeasteroida, Family: Clypeasteridae, Genus: Clypeaster, Species: Clypeaster rosaceus · Clypeasteridae (Sea Biscuit family) · Echinoid (Sand Dollar); whole test (skeleton). Shape: Discoid to inflated sub-pentagonal.
Species
Clypeaster rosaceus (highly likely)
Shell Type
Echinoid (Sand Dollar); whole test (skeleton). Shape: Discoid to inflated sub-pentagonal.
Family
Clypeasteridae (Sea Biscuit family)
Size
Approximately 3-4 inches (75-100mm) in diameter. This is within the standard adult size range, which can reach up to 5 inches.
Color & Pattern
Off-white to light cream base color, likely sun-bleached from its living dark brown or reddish-purple hue. The pattern features five distinct petal-like designs (ambulacra) radiating from the center.
Rarity
Common (beachcombing finds depend on local storm activity and tide cycles).
Habitat
Tropical and subtropical marine environments. Found in shallow subtidal zones, typically in sandy bottoms or seagrass beds (Thalassia) from depths of 0 to 50 meters.
Geographic Range
Western Atlantic, including Florida, the Bahamas, the Gulf of Mexico, and throughout the Caribbean down to Brazil.
Description
An attractive, sturdy echinoid test characterized by a flattened but slightly inflated top. The surface is covered in tiny tubercles where spines once attached. The central feature is the 'petaloid' pattern—five petal-shaped areas where the animal's tube feet protruded. This specimen shows a central gonopore and an asymmetrical natural hole near one petal tip.
Key Features
Closed petaloid ambulacra that are slightly raised; relatively thick and heavy test compared to flat sand dollars; sub-pentagonal outline.
Collector Value
Low to Moderate ($5 - $20). They are highly desirable for coastal decor and beginner collections, though common in their native Caribbean range.
Condition Notes
Fair to Good. The test shows some minor erosion and chips along the edges. The color is significantly bleached by sun exposure. No remaining spines or velvet coating (periostracum-equivalent).
Interesting Facts
In life, these animals are covered in short, dark spines that look like velvet. They use these spines to burrow and move. They are often called 'Sea Biscuits' due to their puffier, bread-like shape compared to flat sand dollars.
Ecological Role
Benthic detritivore; they process sand to eat organic matter, helping to oxygenate the substrate. They are prey for large sea snails like Tun shells and certain triggerfish.
Similar Species
Clypeaster subdepressus (flatter and more circular) and Leodia sexiesperforata (has six physical slits/holes called lunules).
Beach Finding Tips
Look for them in the wrack line after a strong storm or heavy surf. In calm Caribbean waters, they can often be found while snorkeling just outside the surf zone on the sandy edges of seagrass beds.