Genus Ligumia main content.

Genus Ligumia

Family Unionidae



Two species of Ligumia occur in New York state. Only L. nasuta reaches the metro area, occuring in scattered locations in the Hudson, Delaware, and Housatonic rivers. It is more common in western New York state. Although considered by some researchers to be a species of special concern, L. nasuta is not legally protected in the metro area.

Species Summary

Species summary

Ligumia nasuta (Say, 1817)
eastern pondmussel



size: 100mm
beak: umbos extended only slightly above the hinge line
color patterns: black, rarely with fine color rays over the posterior half of the shell; periostracum dark brown; nacre bluish-white but may be purple
shape: elongate, and pointed posteriorly
shell features: distinct posterior ridge
teeth: one to two pseudocardinals in each valve; laterals long and straight


abundance: uncommon status: US, NY: not legally protected; NJ: threatened; CT: special concern
conservation challenges: Appears to be in decline in CT; reportedly widespread but sporadic in NY; little information for NJ; increased efforts should be made to locate and monitor populations of this species, especially in NJ and CT


N.A. distribution: Nova Scotia (Canada) to South Carolina and west to the northern Interior Basin
present metro distribution: NY: upper Delaware River watershed; NJ: Swartswood Lake (upper Delaware River watershed), Delaware River, Cohansey Creek, Mantua Creek, Pennsauken Creek tributary and Raccoon Creek in Gloucester County, Pompeston Creek in Riverton (lower Delaware River watershed), Raritan River; CT: not present in metro area
other regional localities: NY: Allegheny River watershed, eastern Lake Erie watershed, Lake Ontario watershed, southwestern Lake Ontario watershed, St. Lawrence River watershed, Webatuck Creek (Housatonic River watershed), Oswego River watershed, upper Hudson River watershed; NJ: none known; CT: All watersheds except Hudson River watershed
historical localities: NY: Lake Erie watershed; NJ: Stony Brook (lower Hudson River watershed); CT: South central coast watershed


Life History:

habitat: quiet standing water of estuaries, lakes and canals, and slow streams; substrate: silt and sand (varies) Habitat Photo
host: not known


L. nasuta

Left view
left view
Right view
right view
Dorsal view
dorsal view
Profile view
profile view
Posterior end
posterior end drawn to a point
Beak sculpture
beak sculpture double-looped
laterals thin and sharp
pseudocardinals delicate