Common Worm Shell (or Worm Snail Shell)
Phylum: Mollusca > Class: Gastropoda > Subclass: Caenogastropoda > Order: Littorinimorpha > Family: Vermetidae > Genus: Thylacodes > Species: T. squamigerus · Vermetidae (Worm Snail family) · Gastropod (univalve) section/fragment. Tubular and irregularly coiled/curved shape.
Species
Thylacodes squamigerus (or Petaloconchus/Vermicularia species)
Shell Type
Gastropod (univalve) section/fragment. Tubular and irregularly coiled/curved shape.
Family
Vermetidae (Worm Snail family)
Size
Approximately 0.75 inches to 1 inch (18-25 mm) in length, which is a small broken segment. Intact tube structures can grow 2-6 inches or form large colonies.
Color & Pattern
Off-white to cream-tan base color with delicate brownish-orange longitudinal lines and pale transverse growth ridges, creating a subtle cross-hatched pattern.
Rarity
Uncommon to find as clean individual curved tubes on beaches, as they often break or remain cemented to hard substrates.
Habitat
Shallow marine waters attached to hard substrates like rocks, pilings, dead coral, or other shells in intertidal to subtidal depths.
Geographic Range
Western Atlantic, including North Carolina (e.g., Oak Island) down through Florida, the Gulf of Mexico, and the Caribbean.
Description
A curved, tubular segment of an uncoiled worm snail shell featuring distinct longitudinal ridges crossed by concentric growth lines, giving a scaled or scaly surface texture.
Key Features
Hollow interior, irregular non-spiral tubular growth, distinct longitudinal scaly ridges, and lack of septa inside the tube (distinguishing it from polychaete worm tubes).
Collector Value
Low monetary value ($1-$5), but highly interesting as a oddity/curio piece for beachcombers due to its unique worm-like morphology.
Condition Notes
Fair to Good. Fragmentary piece showing clear aperture openings at both broken/natural ends, slight beach wear, but retaining distinct sculpture lines.
Interesting Facts
Despite looking like polychaete worm tubes, these are true gastropods (mollusks). The juvenile starts out as a normal coiled shell, then abandons spiral coiling as it grows and cements itself to a surface, using a mucus net to capture food.
Ecological Role
Sessile filter feeders that play a key role in marine fouling communities and reef structure aggregation by binding substrates together.
Similar Species
Serpulid worm tubes (polychaete tubes made of calcium carbonate, which lack longitudinal ridges and inner shell luster) and Tusk Shells (Scaphopods, which are straight/slightly curved tapered cones without rough scale-like sculpture).
Beach Finding Tips
Look in shell drift lines along North Carolina beaches like Oak Island after winter storms or high tides near rocky jetties, pilings, and oyster beds.
Notes
Oak Island NC