Genus Pyganodon main content.

Genus Pyganodon

Family Unionidae



Pyganodon is a genus of several very similar species whose exact relationship and distribution in New York state remain unresolved. In the metro area, only Pyganodon cataracta is believed to occur. It is widespread in the upper Hudson and Delaware River watersheds, and in other areas of New Jersey, New York state, Connecticut and the Atlantic region.

Species Summary

Species Summary

Pyganodon cataracta (Say, 1817)
eastern floater



size: 100mm (up to 150mm)
beak: sculpture of 5-7 low, evenly raised double loops elevated above hinge line
color patterns: fine green color rays (may be absent in older individuals); periostracum usually greenish
shape: elongate, sub-elliptical to sub-ovate
shell features: smooth, thin shell; nacre bluish-white
teeth: absent


abundance: abundant
status: US, NY, NJ, CT: not legally protected
conservation challenges: Healthy populations of its hosts and its adaptation to a wide range of habitats have helped Pyganodon maintain healthy populations in the metro area. As with other species that are still common and abundant, all known sites should be regularly monitored and new ones sought- particularly in New York


N.A. distribution: Saint Lawrence River (Canada) to Georgia, and west nearly to Michigan
present metro distribution: NY: upper Delaware River watershed; NJ: Passaic River (lower Hudson River watershed); CT: Housatonic River watershed
other regional localities: NY: Lake Ontario watershed, southeastern and southwestern Lake Ontario watersheds, Oswego River watershed, Housatonic River watershed, upper Hudson River watershed, upper Susquehanna River watershed; NJ: most New Jersey watersheds; CT: all watersheds
historical localities: NY: Allegheny River watershed, St. Lawrence River watershed; CT: Southeast coast watershed


Life History:

habitat: slow and standing water, including oxbows and sloughs; substrate of fine sand, mud, and even silt Habitat Photo
hosts: Ambloplites rupestris (Rafinesque, 1817) rock bass; Catostomus commersoni (Lacepede, 1803) white sucker; Cyprinus carpio (Linneaus, 1758) common carp; Gasterosteus aculeatus (Linnaeus, 1758) threespine stickleback; Lepomis gibbosus (Linnaeus, 1758) pumpkinseed; Lepomis macrochirus (Rafinesque, 1819) bluegill; Perca flavescens (Mitchill, 1814) yellow perch


P. cataracta

Exterior view
exterior view periostracum greenish, shell thin; shape elongate, sub-elliptical to sub-ovate
Interior view narce
interior viewnacre white with pink and bluish color
Dorsal view
dorsal view
Profile view
profile view
Interior view No Teeth
interior viewno teeth
Interior view Both Valves
interior viewboth valves