Ivory Marginella, West Indian Marginella
Phylum: Mollusca, Class: Gastropoda, Order: Neogastropoda, Family: Marginellidae, Genus: Prunum, Species: Prunum eburneum · Marginellidae (Margin Shell family) · Gastropod (univalve), spiral/ovate shape with a narrow elongate aperture.
Species
Prunum eburneum
Shell Type
Gastropod (univalve), spiral/ovate shape with a narrow elongate aperture.
Family
Marginellidae (Margin Shell family)
Size
Approximately 10-15 mm (0.4-0.6 inches). Typical size range is 10-20 mm.
Color & Pattern
Glossy white to creamy base color. This specimen shows a subtle beige-tan translucent band. Often naturally ivory-white, the surface is highly polished.
Rarity
Common to Uncommon. While widely distributed, their small size makes them easy to miss during casual beachcombing.
Habitat
Shallow water, intertidal zones to depths of 20 meters; prefers sandy substrates near coral reefs or seagrass beds.
Geographic Range
Western Atlantic: Florida, Caribbean islands, Gulf of Mexico, and south to Brazil.
Description
A small, solid, and highly polished shell. It features a low, rounded spire and a wide body whorl that tapers at the base. The outer lip is thickened (varicose) and smooth, while the columella features several distinct oblique pleats characteristic of the family.
Key Features
High-gloss porcelain finish, four distinct columellar folds, thickened outer lip, and lacking a siphonal notch.
Collector Value
Minimal monetary value (typically $1-$5), but highly desirable for micro-shell collectors due to their aesthetic 'gem-like' appearance.
Condition Notes
Good to Fine. The specimen retains most of its natural luster, though there is slight dulling near the apex suggesting some wave action. The lip appears intact.
Interesting Facts
The living animal has a large, colorful mantle that can completely cover the shell, protecting it from abrasions and keeping it shiny. They are nicknamed 'Rim Shells' because of the thickened outer lip.
Ecological Role
Active predators or scavengers, typically feeding on small invertebrates in the sand. They serve as prey for larger crabs and predatory fish.
Similar Species
Prunum apicinum (smaller, usually with spots on the lip) and Volvarina species (which are typically more slender).
Beach Finding Tips
Check the 'wrack line' or fine shell drift after high tide. Using a small sifter in shallow sandy pools can help locate these tiny specimens.