Endangered Resources Program Species Information
Winged Mapleleaf (Quadrula fragosa)

Overview

Species Overview

Winged mapleleaf (Quadrula fragosa), a mussel listed as Endangered at the Federal and State level, is found in large and medium-sized rivers in the Mississippi River drainage. It is found in mixed gravel and sand in riffles or fast-flowing water. It is very rare wherever it is found. The known host fish are blue and channel catfish.

Status and NHI Documented Occurrences in Wisconsin

The table below provides information about the protected status (State and Federal Status) and the rank (S and G Ranks) for Winged Mapleleaf (Quadrula fragosa). See the Working List Key for more information about the abbreviations used. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. For invertebrates, dots depict locations from the "Invertebrate Atlas," a database with occurrences of rare and common aquatic and select terrestrial invertebrate species found in Wisconsin and adjacent areas. While the invertebrate atlas is a quality assured database, not all records have been verified. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Summary Information State Status: END Federal Status in Wisconsin: LE State Rank: S1 Global Rank: G1 Tracked by NHI: Y Species of Greatest Conservation Need: Y

Detailed Information

Identification: Shell is square, thick, and yellowish-green to light brown with faint rays in smaller shells, becoming greenish-brown or dark brown in larger individuals. A pronounced wing is present posterior to the umbo with radiating rows of ridges. The beak sculpture has two rows of raised nodules that continue down the surface of the shell separated by a furrow. Anterior and posterior ends are squared or truncated. Pseudocardinal teeth are well developed and serrated. Laterals are long. Striated, and straight. The nacre is pearly white, iridescent posteriorly, Up to 4 inches (10.2 cm) long.

Habitat: Occurs in large rivers on a mixed sand and gravel bottom in water two meters or more in depth.

State Distribution: Occurs only in the St. Croix River.

Phenology: The host fish for this species are likely catfish, although this has yet to be proven. Gravid mussels have been found late September to early October.

Management Guidance: Habitat destruction and river pollution have resulted in mussel declines. Protection of habitat and improvements in water quality along with restriction of dredging, impoundments, sand and gravel mining, and navigational improvements would benefit this species. The development of fish runways to facilitate the movement of host species through or around dams could also help to protect the winged mapleleaf. The U.S. Fish and Wildlife Service has developed a recovery plan for this species.

Information compiled from publication PUB-ER-085-99 (now out-of-print).

Photos

Click on a photo to view a larger version. Please considering donating your photos to the Endangered Resources Program for educational uses. See also information regarding use of photos

Photo by Lisie Kitchell, WDNR.

Related Links

Links to Additional Winged Mapleleaf Information

• US Fish & Wildlife Service [Exit DNR]
• MN Department of Natural Resources [Exit DNR]
• Illinois Natural History Survey [Exit DNR]

Other Links Related to Mussels and Clams

• Illinois Natural History Survey [Exit DNR]
• The Field Museum [Exit DNR]
• Conchologists of America [Exit DNR]
• EPA Biological Indicators of Watershed Health [Exit DNR]
• Milwaukee Public Museum [Exit DNR]