Endangered Resources Program Species Information
Purple Wartyback (Cyclonaias tuberculata)

Overview

Species Overview

Purple wartyback (Cyclonaias tuberculata), a mussel listed as Endangered in Wisconsin, is found in large rivers in the western and southern parts of the state. It prefers a stable substrate containing rock, gravel and sand in swift current. Known hosts include bullhead and catfish species.

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 Purple Wartyback (Cyclonaias tuberculata). 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: none State Rank: S1S2 Global Rank: G5 Tracked by NHI: Y Species of Greatest Conservation Need: Y

Detailed Information

Identification: The shell is subrectangular, brown or black and heavy. The beak is low with a wing-like depression behind it. Beak sculpture consists of fine, irregular, broken concentric corrugations. Pseudocardinal teeth are massive and lateral teeth short and heavy. The surface of the shell is yellowish-brown to dark brown and covered with numerous rounded or elongated pustules. Nacre is purple. Length to 5 inches (12.7 cm).

Habitat: Inhabits medium sized rivers with water ranging up to five feet in slow to moderate current. Found in rocky areas with gravel and cobble substrate.

State Distribution: Occurs in the following rivers: Black, Chippewa, Flambeau, Rock, Jump, Mississippi, Namekagon and St. Croix.

Phenology: Yellow bullhead (Ameiurus natalis) and channel catfish (Ictalurus punctatus) are host fish for this species, which breeds from May through July.

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 purple wartyback.

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 Purple Wartyback Information

• Michigan Natural Features Inventory [Exit DNR]
• Illinois Natural History Survey [Exit DNR]
• MN Department of Natural Resources [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]