Shinyrayed Pocketbook: Lampsilis subangulata
Genus/Species: Lampsilis subangulata
Common Name: Shinyrayed pocketbook
Federal Status: Endangered
FL Status: Federally-designated Endangered
FNAI Ranks: G2/S1S2 (Globally: Imperiled/ State: Insufficient data to assign a rank, but ranges from Imperiled to Critically Imperiled)
IUCN Status: Not ranked
The shinyrayed pocketbook is a mid-sized fresh water mussel that can reach a length of 3.3 inches (8.5 centimeters). This species has a smooth, elliptical shaped shell that is yellowish-brown with green rays on the outer shell and a white inner shell. The left valve has two large teeth and the right valve has one large, flattened tooth (University of Georgia 2008, Florida Natural Areas Inventory 2001).
The shinyrayed pocketbook is a filter feeder – filters food from the water, such as plankton and detritus (dead organic matter).
Males release sperm in rivers with low to moderate currents and the females will receive the sperm through a siphon. Eggs are fertilized in the female’s shell and the glochidia (larvae) release into the water when mature. Glochidia are released from late May through mid July when the water temperature ranges from 68°F-74.3°F (20-23.5°C). To attract host fish, the shinyrayed pocketbook produces a long rope of glochidia (larvae) called a superconglutinate . Its resemblance to a fish attracts the host fish to eat the superconglutinate, which allows the glochidia to attach to the fish’s gills. The largemouth bass (Micropterus salmoides) and spotted bass (Micropterus punctulatus) are the primary hosts for the shinyrayed pocketbook (University of Georgia 2008). When the larvae metamorphose into juvenile mussels they release from the fish and settle into their primary habitat.
Habitat and Distribution
Shinyrayed pocketbooks inhabit mid-sized rivers and creeks with a clear or sandy silt floor. This species can be found in the Apalachicola, Chipola and Ochlockonee rivers in Florida, while also being found in the Chattahoochee, Flint, and Ochlockonee rivers in Georgia (Florida Natural Areas Inventory 2001).
Freshwater mussels face a host of threats due to an increased human population and development. The main threat to freshwater mussels is the impounding of waterways. Waterways are impounded for fresh water supply, flood control, and hydropower. Impounding waterways causes the water current’s velocity to decrease, causing sediment to build up in the river and covering the mussels. Impoundments also cause habitat fragmentation, which separates mussel populations and also individual mussels from algae and host fish (U.S. Fish & Wildlife Service 2006). River dredging also threatens to destroy fresh water mussel populations on the river floors. The Asian clam (Corbicula fluminea), an invasive species, can out-compete the shinyrayed pocketbook for resources in its habitat (Florida Natural Areas Inventory 2001). Pesticide and chemical pollution poses a significant threat to mussels since they are filter feeders and may ingest chemicals directly from their habitat.
Conservation and Management
The shinyrayed pocketbook is protected as an Endangered species by the Federal Endangered Species Act and as a Federally-designated Endangered species by Florida’s Endangered and Threatened Species Rule. It is one of the target species in a 7-species Federal Recovery Plan. Specific actions needed to recover the species include (USFWS 2003):
- Secure extant subpopulations and currently occupied habitats and ensure subpopulation viability.
- Search for additional subpopulations of the species and suitable habitat.
- Determine through research and propagation technology the feasibility of augmenting extant subpopulations and reintroducing or reestablishing the species into historical habitat.
- Develop and implement a program to evaluate efforts and monitor subpopulation levels and habitat conditions of existing subpopulations, as well as newly discovered, reintroduced, or expanding subpopulations.
- Develop and utilize a public outreach and environmental education program.
- Assess the overall success of the recovery program and recommend actions.
Other Informative Links
Florida Natural Areas Inventory
University of Georgia
Printable version of this page
Florida Natural Areas Inventory. 2001. Field guide to the rare animals of Florida. http://www.fnai.org/FieldGuide/pdf/Lampsilis_subangulata.PDF
University of Georgia. (2008). Shinyrayed Pocketbook Lampsilis subangulata. Retrieved July 12, 2011, from Museum of Natural History: http://naturalhistory.uga.edu
U.S. Fish & Wildlife Service. (2006, June 8). Current Threats. Retrieved July 7, 2011, from Freshwater Mussels : http://www.fws.gov/midwest/mussel/current_threats.html
U.S. Fish and Wildlife Service. 2003. Recovery Plan for Endangered Fat Three ridge (Amblema neislerii), Shinyrayed Pocketbook (Lampsilis subangulata), Gulf Moccasinshell (Medionidus penicillatus), Ochlockonee Moccasinshell (Medionidus simpsonianus), and Oval Pigtoe (Pleurobema pyriforme): and Threatened Chipola Slabshell (Elliptio chipolaensis), and Purple Bankclimber (Elliptoideus sloatianus). Atlanta, Georgia. 142 pp.
Image Credit FWC