Sphaerium corneum
| Sphaerium corneum | |
|---|---|
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| Conservation status | |
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NE[1]
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Subclass: | Heterodonta |
| Order: | Veneroida |
| Suborder: | Sphaeriacea |
| Family: | Sphaeriidae |
| Genus: | Sphaerium |
| Species: | S. corneum |
| Binomial name | |
| Sphaerium corneum (Linnaeus, 1758) |
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Sphaerium corneum, also known as the European fingernailclam, is a very small freshwater clam, an aquatic bivalve mollusk in the family Sphaeriidae, the fingernail clams.
Contents |
[edit] Description
The shell is fairly globular and can grow up to 9-13.5mm in size. The color of the shell is usually a brown to gray with the juveniles being a yellow color. Their shells exhibit striae, thin parallel rows of elevated lines.[2]
[edit] Ecology
These small clams are found in shallow, freshwater habitats with slow moving waters, including freshwater lakes, rivers and creeks. As with most bivalves, Sphaerium corneum is mainly a filter feeder and thus prefers more eutrophic waters that provide a greater food source. These clams have exhibited a unique ability to climb up plants and structures around their habitat to find more optimal locations for feeding. They also are known to deposit feed in times of low current or food availability. This species has shown a preference however for slow currents in their habitats (Lotic ecosystem), which will provide for a constant flow of food. Their primary food sources are diatoms and other phytoplankton.[2].
S. corneum are sensitive to high pollution levels, particularly organic pollution which fowls the water, preventing them from effective feeding. As such, they are a bioindicator species whose presence may determine a little polluted environment. They are tolerant of anoxic locations however and can survive up to 400 days at 0ºC (32ºF) and 9 days at 20ºC (68ºF). This allows them to burrow down into sand, mud, gravel and other organic matter where oxygen levels are low to avoid predation and to explore other food sources. Their anoxic tolerance also allows them to survive at times where low water levels lead to a quick depletion of oxygen, but as they are sensitive to desiccation, or drying out, they cannot survive for extended periods without water.[2].
These clams can live up to 3 years, although geographic location greatly influences their survival rates. In their native habitats, they may reach their full lifespan, although in the United States and other non-native areas the clams average only 1 to 1 1/2 years. They are considered mature once they reach 4mm. This can be as early as within 3 months from birth in their native habitat. [2].
[edit] Distribution
The native distribution of this species is Palearctic.
- Czech Republic - in Bohemia, in Moravia,[3] least concern (LC)[4]
- Germany - a common species in most of Germany, but it is in listed as endangered (gefährdet) in Thuringia[5]
- Netherlands[6]
- Sweden[7]
- United states - nonindigenous[8]
- and many other countries
In freshwater: standing water and slow-running rivers.
[edit] References
- ^ 2006 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Cited March 24 2007.
- ^ a b c d Rebekah M. Kipp & Amy Benson. 2012. Sphaerium corneum. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. http://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=131 RevisionDate: 3/23/2007
- ^ (Czech) Horsák M., Juřičková L., Beran L., Čejka T. & Dvořák L. (2010). "Komentovaný seznam měkkýšů zjištěných ve volné přírodě České a Slovenské republiky. [Annotated list of mollusc species recorded outdoors in the Czech and Slovak Republics]". Malacologica Bohemoslovaca, Suppl. 1: 1-37. PDF.
- ^ Juřičková L., Horsák M. & Beran L., 2001: Check-list of the molluscs (Mollusca) of the Czech Republic. Acta Soc. Zool. Bohem., 65: 25-40.
- ^ Glöer P. & Meier-Brook C. (2003) Süsswassermollusken. DJN, pp. 134, page 109, ISBN 3-923376-02-2
- ^ http://www.anemoon.org/anm/voorlopige-kaarten/zoetwatermollusken/wetenschappelijk/sphaerium-corneum
- ^ The Large Freshwater mussels - Naturhistoriska riksmuseet
- ^ Amy Benson. 2007. Sphaerium corneum. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. <http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=131> Revision Date: 4/20/2004
