Newsletter: St. Croix 360

Creature Feature: Winged mapleleaf mussels cling to existence in a short stretch of the St. Croix

The winged mapleleaf is an endangered species. Endangered species are animals and plants that are in danger of becoming extinct. Threatened species are animals and plants that are likely to become endangered in the foreseeable future. Identifying, protecting and restoring endangered and threatened species is the primary objective of the U.S. Fish and Wildlife Service’s endangered species program.

What is the winged mapleleaf?

There are an estimated 11,000 winged mapleleaf mussels growing in a six-mile stretch of the St. Croix River near Taylors Falls.

Scientific Name: Quadrula fragosa

Appearance: Winged mapleleaf grow up to four inches long. They have thick shells that are greenish brown, chestnut, or dark brown in color. Their shell, like that of a few other native freshwater mussel species, has several rows of bumps running from the hinge (umbo) to the edge of the shell. The patterns of these rows of bumps, or tubercles, help biologists differentiate this from other, similar mussel species. Faint rays are visible in small shells.

Range: When the recovery plan was approved in 1997 only one population of winged mapleleaf was known to be extant – in the St. Croix River on the border between Minnesota and Wisconsin. Since then four additional populations have been found – in the Saline River and Ouachita River in Arkansas, in the Little River in Oklahoma, and in the Bourbeuse River in Missouri. Additional survey effort is needed to assess and monitor the status and distribution of each population.

For more information about the Winged Mapleleaf or to read other articles, please visit:  St. Croix 360