Variable Nassa (or Tinted Nassa, Dog Whelk)
Phylum: Mollusca, Class: Gastropoda, Subclass: Caenogastropoda, Order: Neogastropoda, Superfamily: Buccinoidea, Family: Nassariidae, Genus: Nassarius, Species: N. vibex · Nassariidae (Nassa mud snails / Dog whelks) · Gastropod (marine snail). Whole single univalve shell. Shape is ovate-conical with prominent spiral cords and axial ribs.
Species
Nassarius vibex
Shell Type
Gastropod (marine snail). Whole single univalve shell. Shape is ovate-conical with prominent spiral cords and axial ribs.
Family
Nassariidae (Nassa mud snails / Dog whelks)
Size
Approximately 8-12 mm (0.3-0.5 inches) in length, as indicated by its small size held between human fingertips. Typical adult range for this species is 10-20 mm.
Color & Pattern
Off-white to light grey base color with dark brownish-grey speckled bands and mottling along the spiral ridges. The interior aperture is whitish to light tan with visible inner teeth/puckering on the outer lip.
Rarity
Very Common
Habitat
Intertidal and shallow subtidal zones, typically found buried just beneath sandy or muddy sediments, estuarine mudflats, and quiet bays.
Geographic Range
Western Atlantic, extending from Cape Cod, Massachusetts south through Florida, the Gulf of Mexico, the Caribbean, and down to Brazil.
Description
A small, sturdy, sculptured marine snail shell with a pointed spire and heavy, lattice-like cross-hatching created by intersecting axial ribs and spiral cords. The aperture is oval with a distinct parietal callus and a notched anterior siphonal canal. The outer lip is thickened and slightly denticulate inside.
Key Features
Distinct coarse reticulated (grid-like) surface sculpture, strong parietal callus around the aperture base, dark blotched bandings following the spiral cords, and a deep anterior siphonal notch.
Collector Value
Low monetary value (under $1-$3) due to high abundance, but highly desirable as a micro-shell specimen or educational addition to a regional Atlantic/Gulf coast beachcombing collection.
Condition Notes
Good / Fair collector grade. The overall form is intact and aperture structure is clearly visible, though the surface shows light natural erosion and beach-wear, blurring some of the finest sculpture details.
Interesting Facts
Living Nassarius snails spend most of their time buried under mud or sand with only their long siphon sticking out like a snorkel. When they detect the scent of decaying animal matter in the water, dozens of them will erupt from the sand simultaneously and race toward the food source as active scavengers.
Ecological Role
Essential detritivores and scavengers in estuarine ecosystems, helping clean the seafloor of dead animal matter and recycling nutrients back into the food web.
Similar Species
Nassarius trivittatus (Threestriped Mud Snail) - tends to have a more elongated spire and finer bead pattern; Nassarius obsoletus (Eastern Mud Snail) - lacks the strong grid-like sculpture and is usually dark brown/black.
Beach Finding Tips
Look along quiet, low-energy estuarine beaches, intertidal mudflats, and bay sandbars at low tide. Sifting through shell hash and fine wrack-line debris often yields numerous intact micro-shells.