Barrens heelsplitter (Lasmigona sp.)

The Barrens heelsplitter is a small, undescribed mussel that is only found in parts of the upper Duck and Caney Fork River drainages in Grundy, Coffee, Warren, and Cannon Counties, Tennessee. It is found mainly in the headwater reaches of streams that drain a flat landscape feature known as the Barrens Plateau. Like many aquatic creatures found in these small streams, it occurs nowhere else in the world.

Barren heelsplitter range map (small scale)

Barren heelsplitter range map (large scale)

Adult Barrens heelsplitters are only about 2 to 3 inches long. They would probably be better named as "bankclimbers," because they are often found in soft sediments near the edge of the stream or actually in the streambank below the waterline. The color of adult Barrens heelsplitters ranges from chestnut brown to almost entirely black.

Little is known about the reproductive habits of this species. Most native freshwater mussels use one or more fish species for help with their reproduction. Females will infect the fish, often by using parts of their body as a lure to attract them, with larval mussels known as glochidia. These "baby" mussels attach to the gills of the unsuspecting fish and grow larger in size until they eventually drop off. While it is likely that the Barrens heelsplitter has one or more host fish species, these species have not yet been identified.

Freshwater mussels, as a group, are the most imperiled animals in the United States. Biologists estimate that approximately 67% of native freshwater mussels are either extinct or are vulnerable to extinction (Williams et al., 1993; Master et al., 1998). Dam construction, water pollution, dredging, water withdrawals, construction, loss of host fish species, and the introduction of invasive exotic mussels, such as the zebra mussel, have led to widespread mussel declines. The Barrens heelsplitter, already a rare species due to its limited geographical range, could be threatened by suburban expansion, water withdrawals, and pollution.

The Service is currently conducting surveys to determine the status and distribution of the Barrens heelsplitter. If you are interested in learning more about this mussel or the Service’s effort to protect it, please contact Geoff Call at 931-528-6481, ext. 213, or via email at geoff_call@fws.gov.