Concentric nut clam

Nuculana concentrica

Family Nuculanidae - nut clams

Bivalve (2 shells); shell oblong with an elongate, pointed, posterior margin; anterior end round; color pale yellow to white; fine concentric ridges on ventral (lower) part of shell , becoming smoother towards the beak; inside of beak with small triangular depression (chondrophore); V-shaped, protruding teeth on both sides of beak (interior lateral margins); posterior margin usually elongate, curved slightly upward, end narrow and pointed (called a rostrum); radial rib on rostrum nearly smooth, not crossed by strong concentric ridges; inside of shell is dull (not pearly); shell margins are smooth, not finely toothed.
Similar Species
The pointed nut clam (N. acuta) is flatter, has thicker, evenly space concentric ridges over the entire shell, and has distinct ridges on the rib of the rostrum (posterior end). Another family of nut clams, Nuculidae, have pearly interiors and finely crenulate (saw-like) margins.
Gulf and bays, sandy muddy bottoms
Maximum Size
1.8 cm (3/4 in)
Other Common Names
Previous Scientific Names