The freshwater pearl mussel, scientific name Margaritifera margaritifera, is an endangered species of freshwater mussel, an aquatic bivalve mollusk in the family Margaritiferidae, the freshwater pearl mussels.
The interior of the shell of this species has thick nacre. The species is capable of making fine quality pearls, therefore it was historically exploited in the search for pearls from wild sources.
The interior of the shell of Margaritifera margaritifera, showing the nacre
Deutsche Post featured Margaritifera margaritifera on a 2002 German € 0.56 postage stamp as part of a series on endangered species of animals 2.
Subspecies
Subspecies within the species Margaritifera magaritifera include:
- Margaritifera margaritifera margaritifera (Linnaeus, 1758)
- Margaritifera margaritifera parvula (Haas, 1908)
- Margaritifera margaritifera durrovensis Phillips, 1928 - critically endangered subspecies in Ireland3. Synonym: Margaritifera durrovensis. This subspecies is mentioned in annexes II and V of Habitats Directive as Margaritifera durrovensis.
Group of live Margaritifera margaritifera in a river bed in Sweden
The anatomy of Margaritifera margaritifera
1. Posterior adductor muscle
2. Anterior adductor muscle
3. Frontal gill
4. Back gill
5. Exhalant aperture
6. Inhalant aperture
7. Foot
8. Pseudotooth
9. The hingeline and ligament
10. Mantle
11. The shell's thickest part, the umbo
Distribution
The native distribution of this species is Holarctic.
- North America: eastern Canada and New England at northwestern of the United States
- Asia: Russian Federation
- Continental Europe, including:
- Austria
- Belgium
- Czech Republic - critically endangered (CR)45. Listed in Decree for implementation, No. 395/1992 Sb. (Czech code) (in Czech: Vyhláška 395/1992 Sb. ve znění vyhl. 175/2006 Sb.) as Critically Threatened species. It's Conservation status in 2004-2006 is bad (U2) in report for European commission in accordance with Habitats Directive.6
- Denmark
- Estonia
- France7
- Germany - critically endangered (vom Aussterben bedroht)8. Listed as strictly protected species in annex 1 in Bundesartenschutzverordnung.
- Great Britain
- Ireland - The Cladagh river contains one of the largest populations surviving in Northern Ireland, estimated minimum 10,000, confined to 6 km stretch of undisturbed river in the middle section.9
- Luxembourg
- Lithuania - extinct
- Poland - extinct1011
- Iberian Peninsula (Portugal and Spain)
- Scandinavian Peninsula (Finland, Norway, rare in Sweden12)
References
External links
|