Genus Elliptio main content.

Genus Elliptio

Family Unionidae

Genus Status


Widespread and abundant, utilizing a variety of hosts, and occuring in most watersheds in the metro area, Elliptio complanata is one of our most familiar freshwater mussels. A second common and widely adapted species of Elliptio, E. dilatata, reaches western New York State drainages but is not recorded from the metro area.

Species Summaries

Species summary

Elliptio complanata (Lightfoot, 1786)
eastern elliptio



size: 100mm (may reach 125mm)
beak: trapezoidal sculpture, low and uninflated
color patterns: fine green color rays only in young individuals; periostracum may be yellowish, brownish or blackish; may have purple nacre
shape: sub-trapeziodal, may be compressed or inflated
shell features: angular posterior ridge, prominent posterior slope
teeth: well-developed triangular pseudocardinals, two in left valve and one in right valve, with rough surfaces; long, sharp laterals


abundance: abundant, often the most abundant unionid present
status: US, NY, NJ, CT: not legally protected
conservation challenges: Careful monitoring of this and all other freshwater mussel species should be done on a regular basis


N.A. distribution: Nova Scotia (Canada) to Georgia; northern parts of the Great Lakes basin from Lake Ontario to the Lake Superior drainage
present metro distribution: throughout the metro region
other regional localities: NY: all watershed drainages except the Allegheny River, Eastern Lake Erie and the Lake Erie watershed, and most of the Niagara River basin above the falls; NJ: all watersheds; CT: all major watersheds


Life History:

habitat: All types of natural freshwater bodies Habitat Photo
hosts: Perca flavescens (Mitchill, 1814) yellow perch, is the only verified host; other, suspected hosts include Fundulus diaphanus (Lesueur, 1817) banded killifish; Lepomis cyanellus (Rafinesque, 1819) green sunfish; Lepomis humilo (Girard, 1858) orange-spotted sunfish; Micropterus salmoides (Lacepede, 1802) largemouth bass; Pomoxis annularis (Rafinesque, 1818) white crappie



E. complanata

Left view
left view
Right view
right view
Dorsal view
dorsal view 
Profile view
profile view;shape sub-trapezoidal
nacre may be purplish
An oblong shell with a pearly white surface.
pseudocardinals triangular
A close-up of the side view of a closed mussel shell.
beak sculpture double-looped
A freshwater mussel with strongly developed lateral and pseudocardinal teeth.
lateral and pseudocardinal teeth strongly developed