Baltic flat mussel
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The Baltic flat mussel ( Limecola balthica ) |
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| Limecola balthica | ||||||||||||
| ( Linnaeus , 1758) |
The Baltic Platt mussel ( Limecola balthica ), also Nordic tellin , Baltic tellin or red bean called, is a mussel from the family of tellins (Tellinidae) in the North and Baltic Sea can be found. But it also occurs in the Atlantic .
features
Shells, skeleton and organs
The almost equally-folded, inflated shell of the Baltic flat mussel is egg-shaped to rounded-triangular. It becomes up to 30 millimeters long. The length / width ratio is about 1: 1.2 and is clearly unequal. The comparatively small eddies are located approximately in the middle of the housing. The front end is rounded, the rear part of the housing is wedge-shaped. The anterior dorsal margin is short, at first almost straight, and then merges into the broadly rounded anterior margin. The posterior dorsal margin is only slightly arched, the posterior end is almost pointed. The ventral or ventral edge is well rounded. The rear end of the case is bent slightly to the right. The case gapes slightly at the rear end.
The brown ligament extends behind the vertebrae for a third of the length of the posterior dorsal margin. There are two cardinal teeth in each valve. In the left valve, the anterior cardinal tooth is furrowed and bilobed, the posterior small. In the right valve, on the other hand, the posterior cardinal tooth is furrowed and two-pointed and the anterior cardinal tooth is small. There are no lateral teeth. The coat is deeply indented, but the shape of the bay is somewhat variable. The ventral boundary of the mantle bay coincides three quarters with the ventral mantle edge, then the bay rises diagonally upwards. There are two sphincter muscles of roughly the same size , the shape of which is slightly different. The anterior sphincter impression is elongated, the posterior sphincter rather ovoid.
The reddish, beige to light gray skin is thick-walled and firm. The surface shows fine ribs and depressions parallel to the edge and finer growth strips. The edge of the case is smooth. The periostracum is a thin, beige-colored or light gray, shiny coating. On the outside there are some darker bands parallel to the edge, often also yellowish, orange or pink. The inside of the shell is usually tinted red, which is why it is also called a red bean. Your siphons are not grown together, very long and flexible.
Similar species
The Baltic flat mussel is more rounded, has a smaller length to width ratio and is less flattened than the calcareous flat mussel ( Macoma calcarea ). The latter is also significantly larger, almost twice as large.
Geographical distribution, habitat and way of life
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The Baltic flat mussel is found in the Atlantic as well as in the North and Baltic Seas . It also occurs on the coasts of the Northern Arctic Ocean. In the East Atlantic it was still to be found about 50 years ago as far as the north coast of the Iberian Peninsula. It has since become extinct there (2016). The southern limit of distribution is currently approximately at the level of the mouth of the Gironde (south-west France).
The Baltic flat mussel lives buried approx. 4 to 10 cm deep, and lying on the left flap, in the mud and mixed mudflats , can also be found in the deeper North Sea. It develops very high population densities up to 2000 individuals per square meter. Its large movable grave foot enables it to be buried quickly when exposed by currents. The flat mussel can also feed itself sipho over its longer inflow , with which it can search the tidal flats for food ( diatoms and bacteria ). Since it does not live particularly deep in the ground and can also survive in frost, it is, just like the cockle , an important food for waders . The subspecies Limecola balthica balthica is particularly adapted to low salinity and tolerates values of three per thousand.
Taxonomy
The taxon put Carl Linnaeus in 1758 as Tellina balthica on. He specified the Baltic Sea as a typical habitat, which he also expressed with the species name. Leach established the genus Macoma in 1819 . The species was placed in the genus Macoma for a long time . Thomas Brown established the genus Limecola in 1848 , which was long forgotten. Genus and species are generally accepted as valid taxa.
The species is divided into two subspecies:
- Limecola balthica balthica (the nominate subspecies), it is native to the North Pacific and the Baltic Sea. The population in the Baltic Sea only immigrated to the Baltic Sea with the Littorina Transgression . However, it is already the product of a hybridization, because it contains only 60 percent balthica balthica and 40 percent balthica rubra genes.
- Limecola balthica rubra (da Costa, 1778), is the subspecies found in the Atlantic and North Sea. The two subspecies hybridize in the contact area z. B. in the Kategatt. <Name = "Luttikhuizen2012" />
supporting documents
literature
- S. Peter Dance, Rudo von Cosel (arrangement of the German edition): The great book of sea shells. Verlag Eugen Ulmer, Stuttgart 1977, ISBN 3-8001-7000-0 , p. 258. (here Macoma baltica )
- Fritz Gosselck, Alexander Darr, Jürgen HJ Jungbluth, Michael Zettler: common names for mollusks of the sea and brackish water in Germany. In: Mollusca. 27 (1), 2009, pp. 3-32. PDF (p. 26)
- Rudolf Kilias: Lexicon marine mussels and snails. 2nd Edition. Verlag Eugen Ulmer, Stuttgart 1997, ISBN 3-8001-7332-8 , p. 180.
- Fritz Nordsieck : The European sea shells (Bivalvia). From the Arctic Ocean to Cape Verde, the Mediterranean Sea and the Black Sea. Gustav Fischer Verlag, Stuttgart 1969, DNB 457713801 , p. 129.
- Guido Poppe. Yoshihiro Goto: European Seashells. Volume 2: Scaphopoda, Bivalvia, Cephalopoda. Verlag Christa Hemmen, Wiesbaden 1993, ISBN 3-925919-10-4 , p. 109.
- Rainer Willmann: Mussels of the North and Baltic Seas. Neumann-Neudamm, Melsungen 1989, ISBN 3-7888-0555-2 , pp. 165-168.
Web links
- Conchological Society of Great Britain and Ireland: Macoma balthica (Linnaeus, 1758)
- Marine Bivalve Shells of the British Isles: Macoma balthica (Linnaeus, 1758) (site of the National Museum Wales, Department of Natural Sciences, Cardiff)
- Marine Species Identification Portal: Macoma balthica (Linnaeus, 1758)
Individual evidence
- ↑ Kerstin Viering: On the bottom of the Baltic Sea. In: Berliner Zeitung . 13./14. August 2016, p. 4 of the magazine supplement .
- ↑ Jeroen M. Jansen, Annelies E. Pronker, Sandra Kube, Adam Sokolowski, J. Carlos Sola, Mikel A. Marquiegui, Doris Schiedek, Sjoerd Wendelaar Bonga, Maciej Wolowicz, Herman Hummel: Geographic and Seasonal Patterns and Limits on the Adaptive Response to Temperature of European Mytilus spp. and Macoma balthica Populations. In: Oecologia. 154 (1), 2007, pp. 23-34. JSTOR 40213053
- ↑ Jeroen M. Jansen, Annelies E. Pronker, Sjoerd Wendelaar Bonga, Herman Hummel: Macoma balthica in Spain, a few decades back in climate history. In: Journal of Experimental Marine Biology and Ecology. 344 (2), 2007, pp. 161-169. doi: 10.1016 / j.jembe.2006.12.014
- ↑ a b PC Luttikhuizen, J. Drent, KTCA Peijnenburg, HW Van Der Veer, K. Johannesson: Genetic architecture in a marine hybrid zone: comparing outlier detection and genomic clines analysis in the bivalveMacoma balthica. In: Molecular ecology. 21 (12), 2012, pp. 3048-3061. doi: 10.1111 / j.1365-294X.2012.05586.x
- ^ Carl von Linné: Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I: Editio decima, reformata. Salvius, Holmia / Stockholm 1758, pp. 1–824. Online at www.biodiversitylibrary.org (p. 677)
- ↑ MolluscaBase: Limecola balthica (Linnaeus, 1758)
- ^ Emanuel Mendez da Costa: Historia naturalis testaceorum Britanniæ, or, the British conchology; containing the descriptions and other particulars of natural history of the shells of Great Britain and Ireland: illustrated with figures. In English and French. - Historia naturalis testaceorum Britanniæ, ou, la conchologie Britannique; contenant les descriptions & autres particularités d'histoire naturelle des coquilles de la Grande Bretagne & de l'Irlande: avec figures en taille douce. En anglois & françois. Millan, White, Emsley & Robson, London 1778 pp. I-XII, 1-254. Online at www.biodiversitylibrary.org (p. 207/8)
