Atlantic Marginella (Commonly known as the 'Coffee Bean' or 'Lettered Marginella')
Kingdom: Animalia; Phylum: Mollusca; Class: Gastropoda; Order: Neogastropoda; Family: Marginellidae; Genus: Prunum; Species: apicinum · Marginellidae (Marginella or Margin Shell family) · Gastropod (univalve); whole shell. Shape: Ovate-cylindrical with a low, obscured spire and a narrow aperture.
Species
Prunum apicinum (90% confidence based on size and apertural shape)
Shell Type
Gastropod (univalve); whole shell. Shape: Ovate-cylindrical with a low, obscured spire and a narrow aperture.
Family
Marginellidae (Marginella or Margin Shell family)
Size
Approximately 8-12mm in length. This is a small specimen, consistent with the juvenile or small adult range for this species which typically tops out at 15mm.
Color & Pattern
Cream-white to pale tan base with three slightly darker, indistinct horizontal bands. The shell possesses a naturally high, porcelain-like gloss. The aperture is white. The color appears natural and not significantly sun-bleached.
Rarity
Common. These are frequently found by beachcombers in Florida and the Caribbean, though their small size makes them easy to overlook.
Habitat
Shallow tropical and subtropical waters, typically found in intertidal zones and shallow subtidal environments. They prefer sandy bottoms, often buried just beneath the surface or near seagrass beds.
Geographic Range
Western Atlantic; commonly found from North Carolina through the Gulf of Mexico, the Caribbean, and south to the West Indies.
Description
A diminutive, polished gastropod featuring a smooth, glossy surface and a thickened outer lip. The shell is characterized by its tear-drop or ovate shape, where the spire is nearly flat and the body whorl dominates the entire form. The aperture is long and narrow, extending nearly the full length of the shell.
Key Features
Four distinct columellar folds (plicae) at the base of the aperture; thickened, callus-like outer lip; naturally glossy texture without the need for polishing; three faint brownish bands.
Collector Value
Low monetary value ($1-$3) due to high abundance, but highly desirable for 'micro-shell' enthusiasts and those building a comprehensive regional collection from the Atlantic/Caribbean.
Condition Notes
The specimen appears to be in Good to Fine condition. The spire shows slight wear, but the body whorl retains its characteristic marginellid luster. No visible predator bore holes or major chips on the outer lip.
Interesting Facts
Marginellas are often called 'rim shells' because of the thickened margin of their outer lip. The living animal has a large, colorful mantle that can completely cover the shell, protecting it from abrasions and maintaining its high gloss. In some cultures, small marginellids have been used historically for decorative beadwork.
Ecological Role
Predatory or scavenging carnivores that feed on small invertebrates and organic matter in the sand. They serve as a food source for larger crabs and predatory fish. No current conservation concerns.
Similar Species
Prunum carneum (larger and more pink/orange), Volvarina avena (more slender/cylindrical), and Gibberula species (smaller with different columellar folds).
Beach Finding Tips
Best found by 'belly-crawling' or sitting near the wrack line or at the 'wash' where tiny shells accumulate. Sifting through fine shell grit with a mesh screen is the most effective way to locate these small specimens.