''Lampsilis fasciola'', the wavy-rayed lampmussel, is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
freshwater mussel
Freshwater bivalves are one kind of freshwater mollusc, along with freshwater snails. They are bivalves that live in fresh water as opposed to salt water, which is the main habitat type for bivalves.
The majority of species of bivalve molluscs ...
, an
aquatic bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
mollusk
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...
in the family
Unionidae
The Unionidae are a family of freshwater mussels, the largest in the order Unionida, the bivalve molluscs sometimes known as river mussels, or simply as unionids.
The range of distribution for this family is world-wide. It is at its most diverse ...
, the river mussels.
Appearance and description
The wavy-rayed lampmussel is a relatively small mussel distributed throughout Southern Ontario and the North-Eastern sections of the United States. The mussel is characterized by its yellow to yellowish-green colour. The mussel receives its name from the numerous thin wavy rays that cover its shell. These waves can be thin and separate or coalesced into significantly wider rays. The beak is slightly elevated above the hinge lines and the beak sculpture consists of 3 to 5 wavy lines. The shell is compressed to inflated (females) in shape and the anterior end is rounded with the posterior end bluntly pointed in males and rounded in females. The mussel's
nacre is typically white or bluish, and the shell in general is rounded and generally symmetrical over the axis. The shell is mostly smooth, excepting certain wrinkles and growth rests that may appear. Wavy-rayed Lampmussles are typically less than , but have been known to grow up to in length.
Habitat
Wavy-rayed lampmussels are historically distributed throughout Southern Ontario as well as 13 U.S. States including the Ohio watershed. In Ontario the mussel has been confirmed in at least four watersheds: the Ausable, Grand, Maitland and Thames river. Mussels live in gravel and sand bottoms in medium-sized streams but are particularly sensitive to changes in their environment.
[
Typically the mussels are found in streams with good currents, and near to riffles, and are rarely found in medium-sized rivers.
Like many mussels, the ]larvae
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
of this species are parasitic and affix themselves to fish hosts. At this stage the larvae consume nutrients from the fish body until they develop into juvenile mussels, and drop off. Fish hosts used by the wavy-rayed lampmussel include the largemouth bass
The largemouth bass (''Micropterus salmoides'') is a carnivorous freshwater gamefish in the Centrarchidae ( sunfish) family, a species of black bass native to the eastern and central United States, southeastern Canada and northern Mexico, but ...
and the smallmouth bass. These fish hosts are especially important to ensure healthy mussel populations.
Threats
Like many fresh water mussels, the wavy-rayed lampmussel is extremely sensitive to changes in water quality. This includes chemical contaminants entering its habitat such as copper, ammonia and chloride, particularly during their glochidial and juvenile life phases.
This, along with loss of habitat has caused a continuous decrease in the mussel's populations. Additionally, the introduction of the invasive zebra mussel
The zebra mussel (''Dreissena polymorpha'') is a small freshwater mussel. The species originates from the lakes of southern Russia and Ukraine, but has been accidentally introduced to numerous other areas and has become an invasive species in ma ...
has resulted in even greater reductions in population. By affixing themselves to hard surfaces the zebra mussels are in direct competition with wavy-rayed lampmussels, and impair their ability to feed, reproduce and move.[
Smaller population may also be affected by predation by muskrats.]
Conservation status
The Canadian Species at Risk Act
The ''Species at Risk Act'' (SARA) (the ''Act'') is a piece of Canadian federal legislation which became law in Canada on December 12, 2002. It is designed to meet one of Canada's key commitments under the International Convention on Biological D ...
listed it in the List of Wildlife Species at Risk
The List of Wildlife Species at Risk currently has more than 800 entries for Canadian wild life species considered vulnerable; including 363 classified as endangered species, —190 threatened species, —235 special concern, and 22 extirpated ...
as being endangered in Canada.[COSEWIC. 2005]
Canadian Species at Risk
Committee on the Status of Endangered Wildlife in Canada. 64 pp., page 13. In 2010 the status of the wavy-rayed lampmussel was reassessed for downgrading due to increased populations. Currently it is listed as "Special Concern" under SARA, as of March 2013, and "Special Concern" under COSEWIC, as of April 2010.[
]
References
{{Taxonbar, from=Q3014688
fasciola
''Fasciola'', commonly known as the liver fluke, is a genus of parasitic trematodes. There are two species within the genus ''Fasciola'': ''Fasciola'' ''hepatica'' and ''Fasciola'' ''gigantica'', as well as hybrids between the two species. Bot ...
Bivalves described in 1820
Taxa named by Constantine Samuel Rafinesque