THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION

Aquatic Invertebrates in Pacific Northwest Freshwater Wetlands
An Identification Guide and Educational Resource

The Thiaridae are not native to the Pacific Northwest, but at least two species have been introduced. They somewhat resemble the common Juga in that their shells are fairly long, thin cones, but they are generally more slender and different in color than the reddish-brown Juga.

The red-rim melania (Melanoides tuberculata) has been introduced into southeastern Oregon and southwestern Montana, as well as many areas of the southern US. Melanoides tuberculata has many small grooves that spiral with the shell and several raised ridges that run perpendicular to the spiral.

Tarebia granifera, also called the quilted melania, has been introduced mostly into the tropical states (FL, TX, HI), but was found in a pond in Twin Falls, Idaho in the early 1990's. They generally require warmer water, so they may not be a significant threat in the Northwest. Tarebia granifera has many rows of bumps that spiral with the shell, and the whorls at the top are flattened and blend into each other. See the pages below for more information.

Species list:
Melanoides tuberculata (introduced - red-rim melania) - outside link
Tarebia granifera (introduced - quilted melania) - outside link

Identifying feature(s): similar to Pleuroceridae; shell is usually a long, fairly thin cone and may have a grainy texture; introduced into southeast OR, ID, southwest MT, and the Southwest
Habitat: warmer waters
Tolerance: moderate