Saw-toothed pen shell

Atrina serrata

Family Pinnidae - pen shells

Bivalve (2 shells); shell wedge or fan-shaped, slightly inflated, very fragile, translucent, beak pointed; color greenish to tan; hinge area long, straight, slightly concave near beak; 30-40 thin radial ribs becoming smoother near ventral (opposite hinge) end; fine sawtooth serrations covering most of shell; interior muscle scar well below edge of nacreous (shiny) layer.
Similar Species
Differs from the stiff pen shell which has its interior muscle bordering the edge of the nacreous layer. Differs from the half-naked pen shell by having more ribs (30-40 vs. 10-15) and having smaller tube-like spines.
Gulf and bay, sandy to muddy bottoms
Maximum Size
30.5 cm (12 in)
Other Common Names
Previous Scientific Names