DEEP: Eastern Pearlshell

Eastern Pearlshell
Margaritifera margaritifera

{External shell of Eastern pearlshell}
External shell
{Internal shell, right valve of Eastern pearlshell}
Internal shell, right valve

{Close-up of pits on the nacre}
Close-up of pits on the nacre
{Hinge teeth of Eastern pearlshell}
Hinge teeth
Key Features
Size: Up to six inches.
Shape: Elongate. Older individuals often have a pronounced ventral curvature that gives them a slight “banana-shaped” appearance.
Periostracum: Thick. Dark. Shell rays absent. Color light brown (juveniles) to black (adults).
Lateral Teeth: Absent.
Pseudocardinal Teeth: Present and well developed—two on the left valve and one on the right valve.
Nacre: Usually white, with faints pits centrally located, each with a faint “tail” that points toward the beak cavity.

Often Confused With...
Eastern Elliptio

The eastern pearlshell is found in streams and small rivers that support trout or salmon populations, and exists in a variety of substrate. This species is not found in lakes or ponds.

{Range Map of Eastern Pearlshell} Range in Connecticut
The eastern pearlshell is found in most major watersheds in Connecticut, though it is most common in the northern and northwestern parts of the State.

The eastern pearlshell is listed as special concern in Connecticut. The scarcity and continual loss of coldwater habitats in the State contribute to its rarity. It is more common in northern New England where there are more coldwater streams and rivers. Its host fishes include Atlantic salmon, brook trout and brown trout. Climate change may negatively affect this species if rivers become too warm to support trout or salmon.

The Freshwater Mussels of Connecticut