Pleurobema furvum

Dark Pigtoe

FWS Focus



The dark pigtoe is a small to medium sized freshwater mussel that has historically been restricted to the Black Warrior River system in northern Alabama.

Scientific Name

Pleurobema furvum
Common Name
dark pigtoe
FWS Category

Location in Taxonomic Tree

Identification Numbers



Characteristic category



The dark pigtoe inhabits sand/gravel/cobble shoals with moderate to strong currents in small to medium sized streams/rivers within the Mobile River Basin.  

River or Stream

A natural body of running water.

Characteristic category

Physical Characteristics

Size & Shape
  • The dark pigtoe is a small to medium sized mussel, occasionally reaching up to 60 millimeters in length.
  • The shell is oval in outline, and moderately inflated. 
  • Beaks are located in the anterior portion of the shell.
  • The posterior ridge is abruptly rounded and terminates in a broadly rounded, subcentral, posterior point.
  • The hinge plate is wide and the teeth are heavy and large, especially in older specimens.
Color & Pattern
  • The periostracum (outermost layer of the shell) is dark, reddish brown with numerous and closely spaced, dark growth lines.
  • The nacre (inner shell layer) approaches white in the umbos and is highly iridescent on the posterior margin.
Characteristic category

Life Cycle

  • The species is gravid (carrying young) in June and releases glochidia (larval stage mussels) in peach to pink-colored conglutinates (Haag and Warren 1997).   
  • The largescale stoneroller (Campostoma oligolepis), Alabama shiner, blacktail shiner, creek chub (Semotilus atromaculatus), and  blackspotted topminnow have been confirmed as suitable hosts (Haag and Warren 1997).  However, in 2015, the Alabama Aquatic Biodiversity Center conducted a host trial with Alabama shiners, blacktail shiners, and tricolor shiners and only produced a total of nine juveniles indicating that all were poor hosts (Johnson 2018).


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